Stainless steel is a special category of steel and contains high chromium and nickel. With particular attention to chromium and nickel, the solvent metal phase of recycling of end-of-life (EoL) ferritic and austenitic stainless steels by remelting is considered Fe–Cr alloy and Fe–Cr–Ni alloy instead of pure iron, respectively. Understanding the element elimination behavior from the solvent metal phase during the remelting process is important for the improvement of the resource efficiency of the stainless steel recycling. The elimination behavior of 23 alloying elements from Fe–Cr alloy and 22 alloying elements from Fe–Cr–Ni alloy were quantitatively evaluated by the thermodynamic method. The conventional metallurgical process, including slagging (oxidation) and evaporation, can efficiently eliminate lots of alloying elements but has its limitation for the elimination of some alloying elements such as copper, antimony, and tin. Moreover, improvement of the elimination is hard to expect with optimizing remelting conditions. Developing novel metallurgical refining processes, such as chlorination and sulfurization, is efficient for eliminating specific alloying elements. However, besides the effort from metallurgical technologies, developing advanced physical separation technologies of collected EoL products in the short term and optimizing the alloy/products design principle in the long term are much more important for improving the resource efficiency of recycling of EoL stainless steel products. Feedback of the alloying elements' elimination behavior during the remelting process to the upstream of the stainless steel cycle is critical.

© 2019, © 2019 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group. The collected end-of-life (EoL) silicon wafers from the discharged photovoltaic (PV) panels are easily contaminated by impurities such as doping elements and attached materials. In this study, the thermodynamic criteria for EoL silicon wafers refining using three most typical metallurgical refining processes: oxidation refining, evaporation refining, and solvent refining were systemically and quantitatively evaluated. A total of 42 elements (Ag, Al, Au, B, Be, Bi, C, Ca, Ce, Co, Cr, Cu, Fe, Ga, Gd, Ge, Hf, In, La, Mg, Mn, Mo, Na, Nb, Ni, Os, P, Pb, Pd, Pt, Re, Ru, Sb, Sn, Ta, Ti, U, V, W, Y, Zn, Zr) that are likely to be contained in the collected EoL silicon-based PV panels were considered. The principal findings are that the removal of aluminum, beryllium, boron, calcium, gadolinium, hafnium, uranium, yttrium, and zirconium into the slag, and removal of antimony, bismuth, carbon, lead, magnesium, phosphorus, silver, sodium, and zinc into vapor phase is possible. Further, solvent refining process using aluminum, copper, and zinc as the solvent metals, among the considered 14 potential ones, was found to be efficient for the EoL silicon wafers refining. Particularly, purification of the phosphorus doped n-type PV panels using solvent metal zinc and purification of the boron doped p-type PV panels using solvent metal aluminum are preferable. The efficiency of metallurgical processes for separating most of the impurity elements was demonstrated, and to promote the recycling efficiency, a comprehensive management and recycling system considering the metallurgical criteria of EoL silicon wafers refining is critical.

© 2019, The Minerals, Metals & Materials Society. Because high-purity silicon is one of the core materials for use in cleaner energy industry, silicon purification techniques have taken on greater importance. An understanding of the thermodynamics of impurity elements in silicon is therefore of great scientific and industrial importance. Experimental and assessment works on the thermodynamics of 23 impurity elements (Ag, Al, Au, B, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Ni, P, Pb, Sb, Ta, Ti, V, W, Zn, and Zr) in silicon melts are reviewed herein, and their activity coefficients in dilute silicon melts are discussed. The parameters suggested for use in assessing the liquid phase in each of the silicon binary systems are selected based on this discussion. The segregation coefficients of impurity elements calculated using the activity coefficients agree well with reported values and are used to evaluate silicon purification by directional solidification. The purpose of this paper is to provide fundamental and systemic thermodynamics knowledge for the development of silicon purification processes.

©2019 The Japan Institute of Metals and Materials. Titanium and its alloys are key materials for various fields. Low cost and high-quality titanium powder production methods are crucial for powder metallurgy (PM) and additive manufacturing (AM) of titanium to significantly decrease the manufacturing cost. In this study, the production of titanium powder from raw material titanium sponge was achieved through the shuttle of the disproportionation reaction and the backward reaction of Ti 2+ to Ti 3+ and Ti metal in molten NaClKCl at 750°C. With the addition of a very small amount of TiCl 2 , over 7 3 70 times of titanium powder in mass comparing to the added Ti 2+ was obtained. The primary particle size of the powder formed based on the disproportionation reaction was approximately 1 µm, while the secondary agglomerated particle size was in the range of 25 3 50 µm. No significant difference of the particle size distribution was found for the experimental runs with different TiCl 2 concentrations and holding times. The proposed production method of titanium powder from titanium sponge is expected to significantly decrease the production cost of titanium powder.

© 2018, The Minerals, Metals & Materials Society. In the present study, a cost-affordable electrorefining process of zirconium (Zr) using an oxycarbide anode, which has been developed for titanium (Ti) smelting, was applied to Zr production. First, the synthesis of Zr oxycarbide by carbothermic reduction of ZrO 2 was investigated, and a dense and conductive ZrC 0.5 O 0.5 anode was successfully produced followed by sintering. The reduction steps of Zr ions in a chloride electrolyte were then electrochemically analyzed; the Zr (IV) ion was electrochemically reduced to Zr metal through the formation of a low-valence Zr (probably Zr (II)) ion. In contrast, Zr (IV) ion was stabilized by F − coordination in a chloride-fluoride electrolyte, and the reduction to Zr metal mainly occurred through a single step. The cathode reaction for electrorefining was checked, and Zr was obtained by galvanostatic electrolysis in a chloride-fluoride bath. The anode reaction using a ZrC 0.5 O 0.5 anode was investigated, and the dissolution of Zr (IV) ion accompanied by CO evolution was observed. Electrorefining experiment showed that a series of electrorefining, anodic dissolution to form Zr ions, transportation of Zr ions from the anode to cathode, and cathodic reduction to produce metallic Zr were appropriately coordinated. For achieving good results in the electrolysis, it is essential to introduce F − ions into the electrolyte and to apply high cathode-current–density (optimally over 1000 mA·cm −2 ). Through the present study, the feasibility of Zr production based on the electrorefining of Zr oxycarbide synthesized by the carbothermic reduction of ZrO 2 was demonstrated in principle.

© The Royal Society of Chemistry. Unique 3D cocoon-like architectures comprising numerous 1D single-crystalline hexatitanate nanobelts with abundant interconnected and open porous structures were successfully grown from chloride flux. In particular, the K2Ti6O13 nanobelt-built architectures (NAs) showed superior selective adsorption of cationic dyes (MB and RhB) and the adsorption capacity of MB was much higher than that of RhB, which was highly related to their porous structures, surface charges and the intrinsic characteristics of dye molecules. The residual contaminants after initial selective adsorption were removed efficiently by the subsequent photodegradation, mainly attributed to the 3D porous NAs with a large surface area quickening the diffusion and mass transport of dyes and reactive species, enhancing the light-harvesting ability and promoting the spatial separation of photogenerated electron-hole pairs. Accordingly, possible mechanisms responsible for crystal growth, construction of 3D NAs, selective adsorption and photodegradation were proposed and fully discussed. More importantly, the K2Ti6O13 photoelectrode exhibited higher photoelectrochemical responses for water splitting than the Na2Ti6O13 electrode, supported by the open-circuit potential measurements, current-potential curves, transient photocurrent responses and EIS analysis, which was consistent with their photocatalytic activities and further highlighted the distinct advantages of 3D porous NAs. Furthermore, the regenerated 3D K2Ti6O13 NAs by photodegradation also showed good recyclability and stability. Overall, our work provided valuable insights into nanoarchitectured design of novel hierarchically porous nanomaterials with multifunctional roles for environmental remediation and solar energy conversion.

A surface tension measurement method based on the maximum bubble pressure (MBP) method was developed in order to precisely determine the surface tension of molten silicates in this study. Specifically, the influence of viscosity on surface tension measurements was quantified, and the criteria for accurate measurement were investigated. It was found that the MBP apparently increased with an increase in viscosity. This was because extra pressure was required for the flowing liquid inside the capillary due to viscous resistance. It was also expected that the extra pressure would decrease by decreasing the fluid velocity. For silicone oil with a viscosity of 1000 mPa.s, the error on the MBP could be decreased to +1.7% by increasing the bubble detachment time to 300 s. However, the error was still over 1% even when the bubble detachment time was increased to 600 s. Therefore, a true value of the MBP was determined by using a curve-fitting technique with a simple relaxation function, and that was succeeded for silicone oil at 1000 mPa.s of viscosity. Furthermore, for silicone oil with a viscosity as high as 10 000 mPa.s, the apparent MBP approached a true value by interrupting the gas introduction during the pressure rising period and by reintroducing the gas at a slow flow rate. Based on the fundamental investigation at room temperature, the surface tension of the SiO2-40 mol% Na2O and SiO2-50 mol% Na2O melts was determined at a high temperature. The obtained value was slightly lower than the literature values, which might be due to the influence of viscosity on surface tension measurements being removed in this study.

The thermodynamic properties and vacancy formation mechanism of Ti-C-O system were investigated by means of empirical calorimetry method and first-principles calculations. The heat of combustion of titanium oxycarbides (TiC1-xOx, 0x1) solid solution were first measured by burning the materials in oxygen bomb calorimeter through sophisticated design experimental environment. The mixing enthalpy of the reaction (1-x)TiC+xTiO=TiC1-xOx was further calculated based on the measured data. Mixing enthalpy was also calculated via efficient first-principles method based on the density functional theory. The vacancies in TiC1-xOx were described as two kinds of models that are disordered and segregated vacancies in titanium oxycarbides solid solution. The calculation results with segregation model show good agreement with the calorimetric results. The heat capacity values were further calculated to deduce the mixing and formation Gibbs free energy. The additive law of the heat capacity and entropy means that the structure of titanium oxycarbides tends to be in order, and this result shows a good agreement with the segregated model in TiC1-xOx. These results are explained on the basis of the interplay between thermodynamic and structural properties, which offered the important theoretic foundation for the novel titanium production process.

A new kind of photovoltaic material, copper yttrium selenide (CuYSe2) was synthesized using a self-propagating high-temperature synthesis method. Here the reaction process of the SHS process of CuYSe2 has been illustrated. The crystalline structure and morphology of the CuYSe2 powders were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The band gap of the CuYSe2 material was estimated to be 1.53 eV based on the UV-vis spectrum of the material. Thin films of CuYSe2 were prepared using a simple, low-cost non-vacuum method. The current-voltage (I-V) behavior of CuYSe2 photovoltaic device was determined. The Ilightfidark ratio of the CuYSe2 device was found to be 2.81, implying that CuYSe2 is a very promising candidate for application as the absorption materials in thin film solar cells. (C) 2017 Elsevier Ltd. All rights reserved.

A controllable and facile process for the preparation of Nb3Sn intermetallic compound nanopowders using NbCl5 and SnCl2 vapors reduced by hydrogen has been developed. The vaporizing rates of the two chlorides are controlled by measuring their mass loss as a function of carrier gas (argon) flow rate at certain vaporization temperatures, respectively. X-ray diffraction (XRD) patterns indicate that hydrogenous Nb3Sn products are obtained under the vaporizing rate of 0.155 g min(-1) for NbCl5 and 0.036 g min(-1) for SnCl2 with the hydrogen flow rate of 2100 ml min(-1) at 1273 K (1000 A degrees C). Results of semi-quantitative analysis by X-ray fluorescence (XRF) demonstrate that the atomic ratio of Nb to Sn in the as-synthesized products is 3.48:1, and the content of (Nb + Sn) is taken up to 89.61 wt pct from the total weight of the products. The products can be purified by vacuum heat treatment. Images of transmission electron microscopy (TEM) show that the products are homogenous particles with a mean diameter of 31 nm. In addition, the reaction ratio of the chlorides and the powder yield are controllable by hydrogen flow rate.

Source of boron and phosphorus as the impurities in the silicon wiresawing slurry was clearly confirmed by systematical study on their elements content variation in the related materials in the cutting process. Extensive studies were concerned about the recovery of silicon particles in the wiresawing slurry. But there is little attention paid to the metal and nonmetal impurities in the slurry, especially for boron and phosphorus, which would affect the efficiency and reliability of the solar silicon cell. It was experimentally tested that for a typical steel sawing wire the boron content is about 4500 ppmw and phosphorus content is about 1000 ppmw, while in the other materials the content of the both impurities is very low. These impurities would be mixed with the silicon and silicon carbide particles after wiresawing cutting, instead of incorporating in the silicon crystal lattices. So conventional acid leaching was considered for using to effectively remove boron and phosphorus, and it was found that under optimal leaching conditions, the removal percentages of iron, boron and phosphorus were 95.50%, 82.95%, and 86.92%, respectively. (C) 2016 Elsevier B.V. All rights reserved.

Electrochemical siliciding of molybdenum in a molten fluoride bath was attempted with the aim of producing an oxidation-resistant MoSi2 film. Prior to this study, the electrochemical siliciding of nickel was investigated. As a result, a nickel silicide film composed of Ni3Si2 and NiSi was obtained. At a high current density of over 50 mA.cm(-2), irregular needle-like crystals were observed and the preferential growth phase was Ni3Si2, which was consistent with the results of a previous study on diffusion coefficient determination using a diffusion couple. On the other hand, at low current density of 10 mA.cm(-2), a nickel silicide film with a smooth surface and smooth interface was formed, which was not observed previously. In the electrochemical siliciding of molybdenum, a dense MoSi2 film was formed along with the deposition of pure silicon. The thickness of the MoSi2 film did not change significantly even when the current density was varied, which indicated that the film growth rate was determined by the diffusion rate of silicon in MoSi2. The film growth rate was significantly higher than that estimated from the diffusion calculation. This may be because not only body diffusion but also fast diffusion, such as grain boundary diffusion, occurred. (C) 2017 The Electrochemical Society. All rights reserved.

Commercial Si3N4 powders coated with 0-30% amorphous Si3N4 nano-powders were fabricated successfully. Amorphous Si3N4 nano-powders coating were prepared through the reduction of silicon tetrachloride (SiCl4) by sodium in liquid ammonia at -45 degrees C. Dense Si3N4 ceramics with 97.2% relative density of theoretic value were obtained from Si3N4 micro-powders coated with 30% nano-powders sintered by spark plasma sintering at 1500 degrees C without sintering additives. (C) 2017 The Ceramic Society of Japan. All rights reserved.

The growth of MoSi2 films by the electrochemical siliciding of Mo was investigated and MoSi2 film formation was attempted on a Ni-based superalloy (CMSX-4) via a two-step coating process. An oxidation test of the MoSi2 film was also performed. A thick MoSi2 film was obtained at a temperature below 1073 K. At a relatively high current density of 100 mA · cm-2, the supply of Si to the Mo surface was too fast and pure Si was deposited outward instead of alloying. The growth rate of MoSi2 at 50 mA · cm-2 was 57 μm · h-1, abnormally fast compared to that by normal diffusion. This indicated that Si diffused through the grain boundaries, rather than through grain bodies. A dense and homogeneous MoSi2 film, approximately 100 μm thick, was successfully formed on CMSX-4. The boundaries in MoSi2/Mo and Mo/CMSX-4 were coherent. After oxidation testing, a multilayer comprising SiO2, MoSi2, Mo5Si3, Mo, an intermediate layer, and CMSX-4 was formed. The SiO2 film was significantly thick at 10-30 μm compared to literature values. To obtain a thin SiO2 film, a MoSi2 layer with fewer defects might be required.

Cyclic voltammetry and square wave voltammetry were performed for TiCl3 at 1023 K, in molten LiCl, LiCl-KCl, NaCl-CsCl and CsCl, respectively. The anodic process from Ti(III) to Ti(IV) is a simple reversible process in all the alkali chloride melts. Ti(III) can be reduced directly to Ti in one step, in CsCl, while Ti(II) will appear before Ti in LiCl, LiCl-KCl and NaCl-CsCl. The electrode potentials of redox couples of titanium species decrease with the decrease of the polarization power of solvent alkali ion. (C) 2017 The Electrochemical Society. All rights reserved.

The silicon-rich powder, which was separated by tuning the particle surface potential combined with centrifugation, contains varied impurities like iron, boron and phosphorus. To remove these impurities, the process of pre-dispersion and magnetic separation was attempted. The aggregates in the silicon rich powder were dispersed by surface potential tuning combined with microwave treatment. According to the DLVO theory and experimental results, the electrostatic repulsion of the particles was largest when the pH value of solution reached 13.0, and the fine silicon-rich particles can be kept sufficiently dispersed at this pH, which was good for the further separation by magnetic field with the 90% removal of iron impurity. The residual iron impurity can be further completely removed by the microwave acid leaching with the mixing acid solutions of hydrofluoric and hydrochloric acid. By combining these enhanced purification techniques, other bothersome impurities such as boron and phosphorus can also be reduced to the requirements of solar grade polysilicon. This work is good for the recycling of silicon scrap materials to the solar grade polysilicon. (C) 2016 Elsevier B.V. All rights reserved.

A series of TiC (x) N (y) O (z) solid solutions were synthesized via solid-state reaction and XRD patterns exhibited a single phase of FCC structure over the whole concentration range. The structural and thermodynamic properties of TiC (x) N (y) O (z) solid solutions were studied using experimental method and first-principles calculations. The difference between the calculated and experimental lattice parameters could be attributed to the vacancies segregated in TiO part. The fitting formulae for lattice parameters and mixing enthalpies were firstly given for TiC (x) N (y) O (z) solid solution over the whole concentration range. The obtained thermodynamic data for TiC (x) N (y) O (z) solid solution properly explained the reaction sequence of the carbothermal reduction of TiO2, providing theoretical foundation for TiC (x) N (y) O (z) solid solution as a kind of prospective material for consuming anode utilized in USTB titanium electrolysis process.

KF is employed as a source of fluoride ions added to the melt to disclose the influence of fluoride on the disproportionation reactions of titanium ions, 3Ti(2+) = 2Ti(3+) + Ti, and 4Ti(3+) = 3Ti(4+) + Ti. The results reveal that the equilibrium transferred to the right direction for the first reaction and the apparent equilibrium constant increased sharply, mainly because of the formation of coordination compounds: TiFi3-i. The accurate values of the equilibrium constants referring to the formation reactions of Ti3+ + iF(-) = TiFi3-i (i = 1-6) in NaCl-KCl melt at 1023 K were evaluated with a best fit least squares method. It is also revealed that the stable states of the coordination compounds are TiF2+, TiF2+, TiF4- and TiF63-. Moreover, the Gibbs free energies for complex formation were estimated. Ti2+ was undetectable when the concentration of fluoride ion was high enough. The equilibrium constant for the formation reaction, Ti4- + 6F(-) = TiF62-, was evaluated. The equilibrium constant, K-c2, for the disproportionation reaction 4Ti(3+) = 3Ti(4+) + Ti, in chloride melt was determined as 0.015.

Rechargeable batteries composed of low-cost and abundant materials operating at room temperature are attractive for grid-scale energy storage application Sodium-ion battery is thought of as an ideal candidate for secondary battery. Hence, ultra-long nanorods of single-crystalline Na0.44MnO2 have been synthesized by co-precipitation method followed by high-temperature calcination. The obtained powder is pure phase with an orthorhombic lattice structure and the morphology is regular. Their electrochemical properties were thoroughly investigated in assembled Sodium-ion cells using cyclic voltammetry, galvanostatic testing, and electrochemical impedance spectroscopy. With applying the as-prepared Na0.44MnO2 as a cathode material for sodium-ion batteries, it exhibits a high reversible initial capacity of 94.1 mAh g(-1) in a voltage range of 2.0-4.0 V vs. Na+/Na at a current density of 50 mA g(-1), and a satisfactory cyclability of 93.3% capacity rentention after 200 cycles is performed in our work. The single-crystalline Na0.44MnO2 with an excellent electrochemical performance proves that it is a potential cathode material for sodium-ion battery.

Nano-sized silicon nitride powders were synthesized through the reduction of silicon tetrachloride (SiCl4) by sodium in liquid ammonia at around -40 degrees C. The product was in uniform particles of several nanometers, and in the amorphous form. The amorphous structure was stable up to 1200 degrees C and turned to the crystal structure of alpha-Si3N4 at 1300 degrees C, and then to beta-Si3N4 structure when heated at temperatures higher than 1450 degrees C. Via spark plasma sintering (SPS) dense bulks with 97.9% relative density of theoretic value and the grain size of 100-300 nm was successfully fabricated at 1500 degrees C without any sintering additives. (C) 2016 Elsevier Ltd. All rights reserved.

Ru-doped lanthanum chromates (LaRuxCr1-xO3) were prepared through a solid-state reaction method. The perovskite pellets with high bulk density over 98% were obtained using the as-prepared LaRuxCr1-xO3 powders as starting materials by spark plasma sintering (SPS) process. The pellets performed high electrical conductivity, which increased with increasing of temperature and ruthenium content (0 <= x <= 0.10). The activation energy of lanthanum chromate was found to be decreased due to the ruthenium doping. (C) 2016 Elsevier Ltd. All rights reserved.

Producing graphene through the electrochemical reduction of CO2 remains a great challenge, which requires precise control of the reaction kinetics, such as diffusivities of multiple ions, solubility of various gases, and the nucleation/growth of carbon on a surface. Here, graphene was successfully created from the greenhouse gas CO2 using molten salts. The results showed that CO2 could be effectively fixed by oxygen ions in CaCl2-NaCl-CaO melts to form carbonate ions, and subsequently electrochemically split into graphene on a stainless steel cathode; O-2 gas was produced at the RuO2-TiO2 inert anode. The formation of graphene in this manner can be ascribed to the catalysis of active Fe, Ni, and Cu atoms at the surface of the cathode and the microexplosion effect through evolution of CO in between graphite layers. This finding may lead to a new generation of proceedures for the synthesis of high value-added products from CO2, which may also contribute to the establishment of a low-carbon and sustainable world.

Studies were conducted to investigate the cathodic behavior of Fe (III) ion in a CaO-MgO-Al2O3-SiO2-NaF-Fe2O3 melt at 1673 K. The kinetic parameters for the charge transfer steps and the reduction mechanism of Fe (III) were investigated by cyclic voltammetry and square wave voltammetry. The results show that two steps are involved during the electrochemical reduction of Fe (III): Fe3+ + e -> Fe2+, Fe2+ + 2e -> Fe. Meanwhile, galvanostatic electrolysis was performed on a molybdenum electrode, which further presents the feasibility of electro-depositing iron in the molten CaO-MgO-Al2O3-SiO2-NaF-Fe2O3 system. (C) 2016 The Electrochemical Society. All rights reserved.

There remains a pressing challenge in the efficient utilization of broad spectrum solar energy in the photocatalytic applications. Here we design and fabricate carbon quantum dots/hydrogenated-gamma-TaON (CQDs/H-gamma-TaON) hollow urchin heterojunctions that can enhance the UV-visible-NIR broad spectrum active photocatalytic property. Novel CQDs/H-gamma-TaON photocatalysts have harnessed UV, visible, and near -infrared light to decompose organic contaminants in aqueous solution. Moreover, efficient photocatalytic hydrogen production as high as 496.5 mot h(-1) with an apparent quantum efficiency of 12.2% under 420 nm (about 61 times higher than that of conventional TaON) was achieved over CQDs/H-gamma-TaON heterojunction, corresponding the order of hydrogen production rate: CQDs/H-gamma-TaON > H-gamma-TaON >gamma-TaON. The improved UV and visible photocatalytic property can be attributed to high surface area from hollow nanostructures and efficient charge transfer based photoluminescence, electrochemical impedance and Mott -Schottky analysis. Especially, the NIR photocatalytic activity from the synergistic effects of the hydrogenation and the decoration of CQDs is ascribed to the efficient charge separation and transfer and up-converted photoluminescence property of CQDs that absorb NIR light and convert into visible light and transfer to visible light photocatalytic H-gamma-TaON. The CC)Ds/H-gamma-TaON heterojunctions may open up more opportunities in the design of efficient broad spectrum active photocatalysts for environmental remediation and clean energy generation. (C) 2015 Elsevier Ltd. All rights reserved.

straightforward electrochemical way. By simply tuning the soft templates and applying a suitable current density, a specific and unique microstructure is obtained. The diameter of the Ni(OH)(2) nano-Vhere is greatly influenced by the current density, the sample obtained at 1 mA"cm(-2) is about 200 nm while the size of that assembled at 6 mA center dot cm(-2) is less than 20 nm. However, the Ni(OH)(2) film prepared at the current density of 2 mA center dot cm(-2) showed the best electrochemical performance for the highly porous surface morphology which contributed to the uniform morphology obtained at this current density. The maximum specific capacitance can be achieved as high as 1460F center dot g(-1) in 2 M NaOH at the scan rate of 2mV center dot s(-1). Such impressive electrochemical properties can be ascribed to the highly porous microstructures and disorder of the amorphous phase which was considered for the better accommodation of repeated volume changes associated with doping-undoping process. The high specific capacitance and remarkable rate capability of amorphous transition metal oxides nanostructures show broad prospect for potential applications in energy conversion and storage devices. (C) 2015 Elsevier Ltd. All rights reserved.

The electrodeposition of carbon films with a Mo2C interlayer was investigated in LiCl-NaCl-Na2CO3 melts at 900 degrees C. Cyclic voltammetry was applied to study the electrochemical reaction mechanism on Mo and Pt electrodes, indicating that, two reduction reactions including carbon deposition and carbon monoxide evolution, may take place on the two electrodes simultaneously during the cathodic sweep. Carbon films with a continuous Mo2C interlayer were prepared by constant voltage electrolysis, showing a good adhesion between Mo substrate and carbon films. The carbon films with a Mo2C interlayer were characterized using X-ray diffraction measurement, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results reveal that carbon materials deposited on the electrodes are mainly composed of graphite and carbon diffusion in Mo (or Mo2C) leads to the formation and growth of Mo2C interlayer. (C) 2015 Elsevier BAT. All rights reserved.

The photochemical conversion of carbon dioxide provides a straightforward and effective strategy for the highly efficient production of solar fuels with high solar-light utilization efficiency. However, the high recombination rate of photoexcited electron-hole (e-h) pairs and the poor photostability have greatly limited their practical applications. Herein, a practical strategy is proposed to facilitate the separation of e-h pairs and enhance the photostability in a semiconductor by the use of a Schottky junction in a bimetal-graphene-semiconductor stack array. Importantly, Au-Cu nanoalloys (ca. 3 nm) supported on a 3D ultrathin graphene shell encapsulating a p-type Cu2O coaxial nanowire array promotes the stable photochemical reduction of CO2 to methanol by the synergetic catalytic effect of interfacial modulation and charge-transfer channel design. This work provides a promising lead for the development of practical catalysts for sustainable fuel synthesis.

In this paper, a novel Cu-Si alloying method has been studied to separate Si from a microsized Si and SiC powder mixture based on the difference in the melting point and density between solid SiC powders and a liquid Cu-Si alloy. The principle of this method is that Si and Cu powders selectively melt to form a liquid phase at a certain temperature, while SiC powders remain in a solid phase and flow up to the surface clue to its lower density relative to the liquid Cu-Si phase. Effects of Si/SiC ratios and Cu fractions in the mixture on separation efficiencies of Si were investigated. For Si/SiC mixtures with an 80 wt% ( and above) Si, the highest separation efficiency was achieved when the mass ratio of Cu to Si was between 5 and 9. Under these conditions, a solid Cu Si alloy ingot and up floated green SiC powders were obtained. The microstructure of alloy ingots comprised of a predominant Cu3Si phase and a scattered pure Si phase. There were not SiC inclusions in the ingot and the carbon content was only 102 ppmw. The recovery ratio of Si was about 90%. The Cu-Si alloying method can separate Si from SiC/Si mixtures effectively, and is a potential approach to recycle Si from cutting slurries in the photovoltaic industry. (C) 2015 Elsevier Ltd. All rights reserved.

Thermoelectric materials can realize significant energy savings by generating electricity from untapped waste heat; however, the coupling of the thermoelectric parameters unfortunately limits their efficiency and practical applications. Herein, rational all-oxide TiC1-xOx@TiOy-TiO2 (x<1, 1<y<2) heterostructures with significantly enhanced thermoelectric properties have been designed, and a high dimensionless figure of merit (ZT) value of up to 0.84 at 973 K was achieved in the all-oxide TiC0.1O0.9@TiOy-TiO2 heterostructures, which is one of the highest values in n-type oxide bulk thermoelectric materials to date. The TiC1-xOx@TiOy heterostructures, which include a thin film of approximately 5-10 nm on the surface of TiC1-xOx compounds prepared by a facile anodization process, exhibit an obvious improvement of the thermoelectric power factor. Furthermore, an excellent dimensionless figure of merit value was obtained in the TiC1-xOx@TiOy-TiO2 heterostructures prepared by the anodization process assisted by the sol-gel chemical route, which can be attributed to the decrease in the carrier concentration via the carrier double-barrier filtering effect. This work develops a facile strategy for synthesizing core-shell heterostructures and demonstrates their superior ability to optimize thermoelectric energy harvesting.

The production of aluminum nitride (AlN) from aluminum metal was investigated in this study. The nitridation of Al (in rod, powder, and thin-plate forms) was facilitated by dissolving the Al2O3 thin films formed on the Al samples with a molten fluoride mixture (KF-45 mol% AlF3, KF, or LiF-50 mol% KF). AlN was formed when NH3 gas was supplied to the Al sample (in both solid and liquid forms) wetted by molten fluoride mixture. The lowest temperature at which AlN was successfully produced was 773 K. No AlN was formed when N-2 or H-2-25% N-2 gas was supplied to the Al sample, even when a molten fluoride mixture was used. The reaction rate for the nitridation of Al powder increased with the temperature and reached 99% after 3 h at 1173 K. AlN thin films of 2-5 mu m thickness were formed on Al thin plates (0.075-1.0 mm thick) at 873 K.

Cyclic voltammetry, chronopotentiometry, and square wave voltammetry were used to investigate electrochemical behavior of Ti(II) ion in a purified CaCl2 melt at a temperature of 1173 K (900 degrees C). The result indicated that the cathodic reduction of Ti(II) ion in the melt was a one-step quasi-reversible process controlled by the diffusion. The diffusion coefficient was determined in a CaCl2-TiCl(0.5 mol/dm(3)) at 1173 K (900 degrees C). The work also demonstrated the feasibility of producing metallic titanium in the as-prepared CaCl2-TiCl2 melts through galvanostatic electrolysis.

Photoelectrochemical (PEC) solar water splitting over oxynitrides is a promising process for renewable hydrogen production. However, the oxynitride heterojunction photoanodes with high charge-separation efficiency and stability, which have unique dimensionality-dependent integrative and synergic effects, are intriguing but still underdeveloped. Here, we design and fabricate the 1D/2D nanorod/nanosheet-assembled tantalum oxynitride (TaON) photoanode with the high PEC activity. Especially, integrated 3D heterojunction photoanodes comprising the 1D/2D barium-doped TaON (Ba-TaON) array and 2D carbon nitride (C3N4) nanosheets decorated with CoOx nanoparticles as a novel stack design were firstly prepared and the 3D CoOx/C3N4/Ba-TaON photoanodes with the remarkable photostability reached the pronounced photocurrent of 4.57 mA cm (2) at 1.23 V vs. RHE under AM 1.5G simulated sunlight. More broadly, the harness charge transfer process of this unique 3D heterojunction photoanode with the intrinsic requirements has been identified by the quantitative analysis combined with the electrochemical impedance and photoluminescence analysis. All the results highlight the great significance of the 3D dimensionality-dependent heterojunction as a promising photoelectrode model for the application in solar conversion. The cooperating amplification effects of nanoengineering from composition regulation, morphology innovation and heterojunction construction provide a valuable insight for creating more purpose-designed (oxy) nitride photoelectrodes with highly efficient performance.

Heterojunction photocatalysts could provide a potential strategy to solve the serious energy and environmental crises. However, the required heterojunction photocatalyts with high charge-separation efficiency and strong redox ability, which have unique dimensionality-dependent integrative and synergic effects, are intriguing but still underdeveloped. Here, for the first time, we design and fabricate 2D/2D heterojunctions between carbon nitride nanosheets and oxygen-vacancies confined in bismuth titanate mesoporous nanosheets. Especially, selective pollutant transformation of rhodamine B and 4-chlorophenol solutions under visible-light irradiation has been conducted by the use of 2D/2D heterojunction photocatalysts. Based on the steady-state and transient photoluminescence spectra and electron spin resonance technology, the Z-scheme energy-transfer mechanism is identified and the photogenerated charge carriers in the 2D/2D heterojunctions display a prolonged lifetime and higher separation compared to those in carbon nitride and bismuth titanate alone. This work will shed light on the rational design of more complex 2D/2D heterojunctions with accompanying applications in solar energy conversion and environmental remediation fields.

A series of titanium-substituted manganese oxides, Na0.44TixMn1-xO2 (x = 0.11, 0.22, 0.33, and 0.44) with the Na0.44MnO2 were prepared by sol-gel methods. The electrochemical characteristics of these compounds, which are different from Na0.44MnO2, were examined in coin-type cells with NaPF6 electrolyte. While the Na0.44Ti0.11Mn0.89O2 and Na0.44Ti0.44Mn0.56O2 delivered lower capacities, the Na0.44Ti0.22Mn0.78O2 showed higher capacities, about 120 mAh g(-1). The Ti-substituted materials exhibited excellent capacity retention over one hundred or more cycles, with 71.8% capacity retention over 450 cycles. Titanium substitution eliminates Mn dissolution. (C) 2015 The Electrochemical Society.

Thermodynamics for chemical vapor synthesis (CVS) of Nb nanopowder in NbCl5-H-2-Ar system was investigated by using FactSage software. The validation experiments were conducted to confirm the thermodynamics points. The results indicate that under the atmospheric pressure, the reduction approach from NbCl5(g) to Nb(s) is a stage-wise process with the formation of complex sub-chlorides, and is controllable at low hydrogen ratio (mole ratio of n(NbCl5):n(H-2)<1:180) and low temperature (<1050 degrees C). Furthermore, a reasonable amount of inert loading gas is favorable to increase the reduction ratio of NbCl5 and the powder yield. The as-synthesized Nb nanopowder with the homogeneous size of 30-50 nm and the powder yield of 85% (mass fraction) is obtained by the CVS process under n(NbCl5):n(H-2):n(Ar)= 1:120:1 and 950 degrees C with the NbCl5 reduction rate of 96.1%.

The equilibrium constant, K-c, of the reaction 3Ti(2+) = 2Ti(3+) + Ti was studied in the molten binary mixtures of LiCl. The accurate values of K-c were calculated by the best-fitting method under consideration of the TiOCl(s) dissolution at temperature of 973 K, 1023 K and 1073 K, respectively. The fitted concentration of O2- was verified by emf method with yttria-stabilized zirconia electrode (YSZE). The influence of the cation radius of electrolyte on the equilibrium constant was studied in molten binary mixtures of LiCl at 1023 K on the basis of the reliable method for obtaining accurate value of K. It was found that the K-c, values decreased from 0.59 to 0.27 with the concentration of LiCl increasing at 1023 K. More importantly, results disclosed that the values of K-c correspond with polarizing power no matter in CsCl-LiCl or KCl-LiCl system. (C) The Electrochemical Society of Japan, All rights reserved.

Considerable efforts have been made to design and discover photoactive nanostructured (oxy) nitride materials that can be used as photoanodes for photoelectrochemical (PEC) water splitting. However, the high recombination rate of photoexcited electron-hole pairs and the poor photostability have greatly limited their practical applications. Herein, a p-type Cu2O/n-type TaON heterojunction nanorod array passivated with an ultrathin carbon sheath (carbon-Cu2O/TaON) as a surface protection layer was produced via a solution-based process. Due to the shape anisotropy and p-n heterojunction structure, the photocurrent density of carbon-Cu2O/TaON heterojunction nanorod arrays as the integrated photoanode, with a maximum IPCE of 59% at a wavelength of 400 nm, reached 3.06 mA cm(-2) under AM 1.5G simulated sunlight at 1.0 V vs. RHE and remained at about 87.3% of the initial activity after 60 min irradiation. Not only is the onset potential negatively shifted but the photocurrent density and photostability are also significantly improved for this photoanode compared to those of TaON and Cu2O/TaON. These improvements are due to a high built-in potential in the p-n heterojunction device that is protected from the electrolyte by being encapsulated in an ultrathin graphitic carbon sheath. Our design introduces material components to provide a dedicated charge-transport pathway, alleviating the reliance on the materials' intrinsic properties, and therefore has the potential to greatly broaden where and how various existing materials can be used in energy-related applications.

An efficient biosorbent was prepared from mangosteen pericarp by saponification with alkaline solution of calcium hydroxide and sodium hydroxide. Batch wise adsorption tests were conducted to investigate the effect of pH, adsorption isotherm, and adsorption kinetics for heavy metal ions. It was found to exhibit fairly good adsorption behavior for heavy metal ions like lead, cadmium, iron, copper, nickel, and zinc ions, with the selectivity order for metal ion adsorption as Fe(III) > Pb(II) > Cu(II) > Cd(II) > Zn(II) > Ni(II). Their adsorption process can be described well by Langmuir model and pseudo-second-order kinetics equation. Among these metal ions, maximum adsorption capacity was evaluated to be 1.48, 1.20, 0.47, 0.35 mol/kg for Cu(II), Fe(III), Ni(II), Cd(II) at equilibrium pH 5.0 (except for Fe(III) at pH 2.8), respectively, while 1.01 mol/kg for both Pb(II) and Zn(II) in the single metal ion solution. The adsorption capability of the modified mangosteen pericarp for heavy metal ions can be attributed to the functional groups of carboxylic acid and plant polyphenol contained in the pericarp. Large adsorption capacity and short adsorption equilibrium time indicated that the saponified mangosteen pericarp gel can be used as a promising adsorbent for the removal of aforesaid heavy metal ions from waste effluents.

A new sodiothermic reduction process of TiO2 in CaCl2 melt was proposed aimed at fine Ti powder preparation. The chemical analysis and direct potentiometric methods were used to investigate the reaction pathway of sodiothermic reduction in CaCl2 melt. The as-prepared samples were characterized by X-ray diffraction and scanning electron microscopy. It was found that when reductant of Na was added into the CaCl2 melt, Ca2+ was reduced to Ca by Na and Ca dissolved in the CaCl2 melt. The whole melt would have the reducing power with dissolved Ca. Using this melt as a reaction medium, fine and uniform Ti powder with a purity of around 99 mass pct was successfully produced at 1173 K (900 A degrees C). In addition, as the CaCl2 melt could dissolve about 20 mol pct CaO, it was found that the molar ratio of TiO2 and CaCl2 should be 1:20 to eliminate the by-product CaO from the reaction interface within the experimental period to continue the reduction.

NaCl-KCl-TiClx., was prepared via using titanium sponge to reduce titanium tetrachloride in a NaC1 KC1 melt under a negative pressure at 1023K. The relationship between titanium valence states and [F]/[Ti] molar ratios was investigated with successive adding potassium fluoride in the pre-prepared NaCl-KCl-TiClx It was found that the average valence of titanium ions tended to be stable around 3.0 when [F]/[Ti] molar ratio was greater than 1.80. The equilibrium redox potentials, E-Ti(3+)/Ti2+, En(4+)/Ti3+, E-Ti(3+)/Ti and E-Ti(2+)/Ti, were also calculated through the obtained concentration of equilibrium titanium ions with different molar ratios of [F]/[Ti]. Meanwhile, the influence of the fluoride anion on over-potential and characteristics of titanium electrodeposition were investigated through changing the molar ratio of [F]/[Ti]. The results showed that, with the increasing of [F]/[Ti] molar ratios, the grain size of electrodeposition products became smaller, while the over-potential was higher.

TiCl (x) (x = 2.17) was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiCl (x) melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30 x 10(-6).

With the growing demands for large-scale applications, rechargeable batteries with cost-effective and environmental-friendly characteristics have gained much attention in recent years. However, some practical challenges still exist in getting ideal electrode materials. In this work, three-dimensional FeWO4/graphene mesoporous composites with incredibly tiny nanospheres of 5-15 nm in diameter have been synthesized by an in situ self-assembled hydrothermal route. First-principles density functional theory has been used to theoretically investigate the crystal structure change and the insertion/extraction mechanism of Li and Na ions. Unlike most graphene-coated materials, which suffer the restacking of graphene layers and experience significant irreversible capacity losses during charge and discharge process, the as-prepared composites have alleviated this issue by incorporating tiny solid nanospheres into the graphene layers to reduce the restacking degree. High capacity and excellent cyclic stability have been achieved for both Li-ion and Na-ion batteries. At the current density of 100 mA g(-1), the discharge capacity for Li-ion batteries remains as high as 597 mAh g(-1) after 100 cycles. The Na-ion batteries also exhibit good electrochemical performance with a capacity of 377 mAh g(-1) at 20 mA g(-1) over 50 cycles. The synthetic procedure is simple, cost-effective and scalable for mass production, representing a step further toward the realization of sustainable batteries for efficient stationary energy storage.

SiO2 nanospheres were prepared according to a straightforward approach and evaluated as an anode material for lithium-ion batteries. The morphologies display that the obtained amorphous SiO2 powder has good uniform nanospheres with an average diameter of 400 nm. The SiO2 anode shows an initial charge capacity of 622.1 mAh g(-1) and it still remains at 876.7 mAh g(-1) even at a rate of 1 C over 500 cycles, showing a certain degree of increase. It can be considered that the superior performances are attributed to the partial generated Si, Li2O, and Li4SiO4 matrixes acting as a shielding layer, hence improving the lithium storage performance. In short, the discussed results suggest that SiO2 nanosphere is a promising anode material to improve the electrochemical performances for lithium-ion batteries.

The structural properties and mixing thermodynamic of TiC1-xNx and TiO1-xNx (0x1) solid solutions have been studied by X-ray diffraction method and first-principles calculations. The TiC1-xNx and TiO1-xNx compounds were synthesized via solid-state reaction and the analysis of XRD patterns show the properties of continuous solid solutions over the whole composition range. Thermodynamic analyses and structural stability studies were performed based on the mixing enthalpies and electronic structures. The mixing enthalpies of TiC1-xNx and TiO1-xNx can be fitted using a second-degree polynomial with the increasing of supercell. The first-principles calculations results reveal that the TiO1-xNx shows large number vacancies segregated in TiO-part. The charge redistributed around Ti vacancy constitutes the main contribution to the stabilization rather than the Ti-Ti bond across the O vacancy through analyzing the electron density difference plots and PDOS . These results provide theoretical basis for the development and application of the TiC1-xNx and TiO1-xNx solid solutions.

The equilibrium between metallic titanium and titanium ions (Ti2+, Ti3+) dissolved in LiCl-KCl melts and the influence of the electrolyte composition on the equilibrium were investigated. The accurate concentrations of titanium ions had been obtained based on a reliable approach for taking samples. Furthermore, accurate values of the equilibrium constants were calculated by the best-fitting method under the consideration of the TiOCl dissolution. The influence of the electrolyte composition on the equilibrium was evaluated by determining the equilibrium constant K-c between titanium metal and titanium ions in LiCl-KCl melts with different concentration of LiCl. It was shown that LiCl could affect the equilibrium and the K-c values decreased with the increase of concentration of LiCl. (C) 2013 Elsevier B.V. All rights reserved.

The work presents a direct preparation of Ni-Fe alloys through electrochemical approach in molten sodium hydroxide. Fe2O3 and NiO were used as raw materials which were fully mixed and sintered into pellet at 1200 degrees C The sintered oxide pellet and nickel rod were applied as cathode and anode, respectively. A constant voltage was performed in molten sodium hydroxide at 550 degrees C. The results indicate that the oxide pellets were reduced to form Ni-Fe alloys with the electrolyzing time of longer than 3 hours.

alpha-Fe2O3 nanorods have been successfully obtained by annealing alpha-FeOOH precursor nanorods synthesized by a facile hydrothermal method. The electrochemical performance of the asprepared alpha-Fe2O3 a nanorods as anode materials for sodium-ion batteries is tested using galvanostatic charge/discharge cycling. The result indicates that the pcsudocapacitor effect dominates the charge/discharge process. The alpha-Fe2O3 synthesized at different temperature indicates that alpha-Fe2O3 with a high crystallinity manifests relatively better cycling ?erformance with a capacity of 177 mAh g-1 after 20 cycles at current density of 200 mA g(-1). While the current density increases to 500 mA g-1, the corresponding discharge capacity can still remain as much as 132 mAt center dot g(-1) Meanwhile, XPS spectrum results of the active electrode material asprepared and after a discharge process disclose that the electrochemical reaction mechanism happens in the half-cell sodium ion battery is the reduction of Fe2O3 to Fe.

Niobium doped indium tin oxide (ITO:Nb) thin films were fabricated on glass substrates by RF magnetron sputtering from one piece of ceramic target material at room temperature. The bias voltage dependence of properties of the ITO:Nb films were investigated by adjusting the bias voltage. Structural, electrical and optical properties of the films were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible spectroscopy, and electrical measurements. XRD patterns showed a change in the preferential orientations of polycrystalline crystalline structure from (222) to (400) crystal plane with the increase of negative bias voltage. AFM analysis revealed that the smooth film was obtained at a negative bias voltage of -120 V. The root mean square (RMS) roughness and the average roughness are 137 nm and 1.77 nm, respectively. The films with the lowest resistivity as low as 1.45 x 10(-4) Omega cm and transmittance over 88% have been obtained at a negative bias voltage of 120 V. Band gap energy of the films, depends on substrate temperature, varied from 3.56 eV to 3.62 eV. (C) 2013 Elsevier Ltd. All rights reserved.

A single phase titanium oxycarbonitride TiC0.25O0.25N0.5 was prepared by sintering a homogenous mixture of TiO, TiC and TiN with a molar ratio of 1:1:2 by spark plasma sintering (SPS) at 1873 K. TiO0.25C0.25N0.5 was then used as the consumable anode for the USTB titanium process and the anode dissolution process was investigated by electrochemical methods. The results showed that TiO0.25C0.25N0.5 was electrochemically dissolved into Ti2+ in the NaCl-KCl melts as determined by square-wave voltammetry analysis and simultaneously CO as well as N-2 evolved in the anode as detected by mass spectroscopy. And TiO0.25C0.25N0.5 has exhibited a similar electron transfer resistance as TiC0.5O0.5 and TiN as measured by electrochemical impedance spectroscopy (EIS) analysis. By galvanostatic electrolysis, the cathode products were proved to be pure titanium powders. The results indicated that TiO0.25C0.25N0.5 is a suitable consumable anode for the USTB titanium process.

The structural, electronic and elastic properties of TiCxN(1-x), TiCxO(1-x) and TiOxN(1-x) alloys have been investigated by using the plane-wave pseudopotential method within the density function theory. The present lattice parameters and bulk modulus of TiCxN(1-x) alloys generally follow the Vegard's law. The elastic properties of TiCxN(1-x) alloys presented as a function of concentration reveal the anisotropy and ductility. The prediction of elastic properties for TiOxN(1-x) alloys has been presented due to the consistency between the calculated results and the experimental results for TiCxN(1-x) and TiCxO(1-x) alloys. The partial density of states (PDOS) and total density of states (DOS) for the binary and ternary compounds have been obtained, and the metallic behavior of these alloys has been confirmed by the analysis of DOS. (C) 2014 Elsevier B.V. All rights reserved.

A novel SiOxCy film is successfully fabricated by electrodeposition on a carbon paper substrate with vinyl trichlorosilane as the precursor in air. It has been found that the SiOxCy film is evenly and uniformly distributed on the carbon paper. The long-term cycling stability of the SiOxCy film anode is tested at a rate of 1 C for 1000 cycles, showing that the charge capacity decreases from 1919.8 mAh g(-1) to 1020.5 mA h g(-1) over 1000 cycles, suggesting good long-term cycling stability. The good cycling stability of the SiOxCy film anode is attributed to the ordered structure of the SiOxCy film. Moreover, the interwall space could provide a buffer for Si expansion during the Li insertion/extraction process, thus improving the cycle life of Si anodes.

Nb-Al intermetallic nanoparticles were directly synthesized via sodiothermic reduction process in molten salts using NbCl5 and AlCl3 as the raw materials. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The NbCl5 and AlCl3 were dissolved in LiCl-KCl-CaCl2 or LiCl-KCl-NaCl-CaCl2 molten salts forming a homogeneous system. It was found that a series of intermetallic nanoparticles, such as Nb3Al, Nb2Al, NbAl3 and Nb2Al/NbAl3, were successfully synthesized at low temperature of 350-500 degrees C using the homogeneous molten salt systems. The phase transformations of Nb3Al, Nb2Al and NbAl3, were achieved via the controllable variation of molar ratio of Nb to Al. Furthermore, the influence of the reaction temperature on the particle size of the intermetallic nanoparticles was also investigated. (c) 2013 Elsevier Ltd. All rights reserved.

Due to their small footprint and flexible siting, rechargeable batteries are attractive for energy storage systems. A super-valent battery based on aluminium ion intercalation and deintercalation is proposed in this work with VO2 as cathode and high-purity Al foil as anode. First-principles calculations are also employed to theoretically investigate the crystal structure change and the insertion-extraction mechanism of Al ions in the super-valent battery. Long cycle life, low cost and good capacity are achieved in this battery system. At the current density of 50 mAg(-1), the discharge capacity remains 116 mAhg(-1) after 100 cycles. Comparing to monovalent Li-ion battery, the super-valent battery has the potential to deliver more charges and gain higher specific capacity.

Ta3N5 nanorod arrays were fabricated by nitridation of fluorine-containing tantalum oxide (F-Ta2O5) nanorod arrays grown in situ on Ta substrates by a one-pot vapour-phase hydrothermal induced selfassembly technique. In this protocol, the in situ generation and the morphology of arrays elaborately adjusted by reaction time, play a vital role in the formation of the F-Ta2O5 nanorod arrays and a highly conductive interlayer between the nanorods and the substrate. Due to the shape anisotropy, ordered hierarchical structure and high surface area, a high photoelectrochemical activity was achieved by the optimum Ta3N5 nanorod photoelectrode with a photocurrent density of 1.22 mA cm(-2) under AM 1.5G irradiation at 1.23 V vs. RHE (reversible hydrogen electrode). Furthermore, a higher and more stable photocurrent was demonstrated by combining the highly active Ta3N5 nanorods with stable Co3O4/Co(OH)(2) (Co3O4/Co(II)) bilayer catalysts when compared with that demonstrated for Co(II)/Ta3N5 and Co3O4/Ta3N5 photoelectrodes, exhibiting that not only is the onset potential negatively shifted but also the photocurrent and the stability are significantly improved, which is correlated to an order of magnitude reduction in the resistance to charge transfer at the Ta3N5/H2O interface. Specifically, about 92% of the initial stable photocurrent remains after long-term irradiation at 1.23 V vs. RHE. At 1.23 V vs. RHE, the photocurrent density of Co3O4/Co(II)/Ta3N5 arrays reached 3.64 mA cm(-2) under AM 1.5G simulated sunlight at 100 mW cm(-2), and a maximum IPCE of 39.5% was achieved at 440 nm. This combination of catalytic activity, stability, and conformal decoration makes this a promising approach to improve the photoelectrochemical performance of photoanodes in the general field of energy conversion.

Titanium nitride (TiN) was used as consumable anode to produce metallic titanium in molten salts. The electrochemical dissolution of TiN was investigated. It was found that nitrogen (N-2) was monitored at the anode during electrolysis. The titanium ion species was changed between Ti2+ and Ti3+ depending on the electrochemically dissolving potentials of TiN. Furthermore, the product on the cathode was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that pure titanium powders can be prepared by the TiN electro-refining in a molten salt bath. (C) 2013 Elsevier B.V. All rights reserved.

A novel recovery process for effective separation of silicon and silicon carbide micropowders from the wiresawing slurry was proposed, based on the difference in their size and surface charging state. The surface charging levels of silicon and silicon carbide particles were found to be obviously different by tuning the solution pH values, so the pre-dispersed mixed particles in the suspension will be subject to different static electrical repulsion and particle mass. Under the same centrifugation filed, Si and SiC particles will have distinctly different separation tendency. Experimental results show that the silicon microparticles tend to suspend in the upper part of the vessels whereas the silicon carbide particles will settle down to the bottom quickly, leading to the effective separation of above powders. The optimal results show that Si content can reach 91.8% in the Si-rich powder and 4.8% in the SiC-rich powder by separating the mixed powder with Si 24.9% and SiC 70.1% as the raw material. (C) 2013 Elsevier B.V. All rights reserved.

Mangosteen peel, rich in polyphenolic compounds, was used to prepare the adsorbent exhibiting highly selective adsorption for Cr(VI) over other metal ions such as Pb2+, Fe3+, Zn2+, Cd2+, and Cr3+ at the pH values of 1 similar to 4. The chemical modification method proposed by using calcium hydroxide is quite cost-effective and ecofriendly without using any toxic reagents or causing any secondary pollution. The adsorption isotherm results revealed that the adsorption of Cr(VI) on the gel fit well the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) at pH levels 1, 2, 3, and 4 was evaluated to be 2.46, 2.44, 1.99, and 2.14 mol/kg, respectively. The adsorption mechanism for Cr(VI) on the saponified gel was verified to follow an esterifiaction reaction coupled with the reduction of Cr(VI) to Cr(III) in which H+ plays a role of promoter. Thus, modified mangosteen peel gel has the prominent selectivity and low cost for Cr(VI) removal.

The equilibrium between metallic titanium and titanium ions, 3Ti(2+) a double dagger OE 2Ti(3+) + Ti, in NaCl-KCl equimolar molten salt was reevaluated. At a fixed temperature and an initial concentration of titanium chloride, the equilibrium was achieved by adding an excess amount of sponge titanium in assistant with bubbling of argon into the molten salt. The significance of this work is that the accurate concentrations of titanium ions have been obtained based on a reliable approach for taking samples. Furthermore, the equilibrium constant was calculated through the best-fitting method under the consideration of the TiOCl dissolution. Indeed, the final results have disclosed that the stable value of K-C could be achieved based on all modifications.

A cost-effective biosorbent was prepared by a green chemical modification process from muskmelon peel by saponification with alkaline solution of Ca(OH)(2). Its adsorption behavior for lead ions was investigated and found to exhibit excellent adsorption properties. Results showed that the optimal equilibrium pH range for 100 % adsorption is from 4 up to 6.4. Adsorption equilibrium was attained within 10 min. The adsorption process can be described well by Langmuir model and pseudo-second-order kinetics equation, respectively. The maximum adsorption capacity for lead ions was found to be 0.81 mol/kg. Pectic acid contained in the muskmelon peel is the main factor responsible for the uptake of lead ions onto the gel, and the chemical modification process presented in this study can be assumed effective to prepare other similar biomaterials. The large adsorption capacity and the fast adsorption rate indicated that chemically saponified muskmelon peel gel in present study has great potential to be used as a cost-effective adsorbent for the removal of lead ions from the water.

Chalcopyrite-type CuInSe2 (CIS) nanoparticles were successfully synthesized by Se powder, CuCl, and InCl3 as raw materials and water as solvent at room temperature based on the principles of simultaneous equilibrium. The size of nanoparticles ranges from 20 to 50 nm in diameter. The crystalline structure and morphology of the CIS nanoparticles were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy analysis (XPS), and transmission electron microscopy (TEM). The CIS nanoparticles were further enhanced after heat treatment at 500 degrees C for 2 h. The CIS film was fabricated by a mixture of CIS nanoparticles and novolac resin with a weight percentage of 30% by spin coating. The photoelectrical properties of such CIS films were measured and the results show an incident light density of 7.63 mW cm(-2) with the bias voltage of 0.4 V, and the current density could approach 4.10 mA/cm(2) giving an on/off switching ratio of 2.0. (C) 2013 Elsevier B.V. All rights reserved.

The hierarchical photocatalysts of Ag-AgCl@Bi20TiO32 composites have been successfully synthesized by anchoring Ag-AgCl nanocrystals on the surfaces of mesoporous single-crystalline metastable Bi20TiO32 nanosheets via a two-stage strategy for excellent visible-light-driven photocatalytic activities in the Z-scheme system. First, the single-crystalline metastable Bi20TiO32 nanosheets with tetragonal structures were prepared via a facile hydrothermal process in assistance with the post-heat-treatment route using benzyl alcohol. Especially, the mesoporous Bi20TiO32 nanosheets showed high photocatalytic activity for the degradation of rhodamine B dye under visible-light irradiation. Then, the as-prepared mesoporous Bi20TiO32 nanosheets were used as a support for loading Ag-AgCl nanocrystals using the deposition-precipitation method and irradiation-reduction process to fabricate the Ag-AgCl@Bi20TiO32 composites. Inspiringly, the hierarchical Ag Ag-Cl@Bi20TiO32 photocatalyst has the higher photocatalytic performance than Ag-AgCl nanocrystals and mesoporous Bi20TiO32 nanosheets over the degradation of rhodamine B and acid orange 7 dyes, which is attributed to the effective charge transfer from plasmon-excited Ag nanocrystal to Bi20TiO32 for the construction of a Z-scheme visible-light photocatalyst. This work could provide new insights into the fabrication of hierarchically plasmonic photocatalysts with high performance and facilitate their practical application in environmental issues.

Garlic peel was used as the raw material to prepare the biosorbent by a simple chemically modified process named saponification with alkaline solution. The obtained garlic peel particle was tested to exhibit fairly good affinity to cadmium ions in the aqueous solution. In comparison, its adsorption behavior was also examined for other metal ions including Cu2+, Fe3+, Zn2+, Pb2+, and it shows the adsorptive selectivity for metal ions is as follows: Fe3+> Pb2+> Cu2+> Cd2+ approximate to Zn2+. The adsorption capacity of cadmium on the garlic peel gel is 0.61 mol/kg, or 68.6g/kg, which is potential to be one of the cost-effective adsorbents for the removal of heavy metal ions from aqueous solution.

Purification of wastewater containing dyes just by photocatalytic degradation under visible light irradiation is usually a slow process, especially for the cases of high concentration dyes in the water. From the viewpoint of economy and efficiency, decreasing the dyes concentration of wastewater to an optimal level suitable for visible light photocatalytic degradation is one of the methods to adopt. Based on the above ideas, a novel treatment process was designed for dye removal from water, which consisted of biosorption and photocatalysis under the visible light irradiation. High concentration (similar to 100mg/l) of dye waste water will be decreased rapidly after fast biosorption onto the biosorbents such as saponified apple juicing residue, sweet-stick bagasse, and then the obtained waste water with low concentration (similar to 5mg/l) of dye will much easier be degraded thoroughly under visible light irradiation in short time. The basic experiments were conducted to evaluate the principal characteristics of these two unit operations, and their removal behaviour for dye molecules from water was clarified respectively. The process exhibits outstanding advantages, i.e., much faster, more thorough, and energy saving, showing the great perspective for the dye waste water cleaning in the industry.

Conventionally, rechargeable batteries with a fast charge-discharge rate, while being able to be implemented in large-scale applications with low prices, are critical for new energy storage systems. In this work, first-principles simulations were employed to theoretically investigate the insertion of sodium into the Na2Ti3O7 structure. The result discovered that the theoretical capacity of Na2Ti3O7 was 311 mA h g(-1). Furthermore, a microspheric Na2Ti3O7 material consisting of tiny nanotubes of ca. 8 nm in outside diameter and a few hundred nanometers in length has been synthesized. The galvanostatic charge-discharge measurements, using the as-prepared Na2Ti3O7 nanotubes as a working electrode with a voltage range of 0.01-2.5 V vs. Na+/Na, disclosed that a high capacity was maintained even under an ultrafast charge-discharge rate. At a current density of 354 mA g(-1), the discharge capacity was maintained at 108 mA h g(-1) over 100 cycles. Even at a very large current density of 3540 mA g(-1), the discharge capacity was still 85 mA h g(-1). HRTEM analysis and electrochemical tests proved that sodium ions could not only intercalate into the Na2Ti3O7 crystal, but could also be stored in the intracavity of the nanotubes. All of the results disclose that the as-prepared Na2Ti3O7 nanotubes are able to be used as anode materials in large-scale applications for rechargeable sodium-ion batteries at low cost while maintaining excellent performance.

Due to its great importance in fundamental research and practical applications, tailored synthesis of anatase TiO2 dominated with highly energetic {001} facets has attracted extensive interest. Here, Bi2O3 quantum dots decorated anatase TiO2 with exposed {001} high energy facets had been firstly prepared on graphene sheets by a simple and feasible strategy using the hydrofluoric acid. During the synthesis process, TiO2 nanosheets were homogeneously decorated with surface enrichment of Bi2O3 quantum dots and graphene was uniformly covered with a large number of Bi2O3/TiO2 composites. The morphologies, structural properties and photocatalytic performance of the resultant Bi2O3/TiO2/graphene composites were investigated and were characterized by X-ray diffraction, scanning electron microscopy. transmission electron microscopy, X-ray photoelectron spectra, UV-vis diffuse reflectance spectrum and photoluminescence spectra. A certain amount of Bi2O3 quantum dots coating on TiO2 nanosheets exhibited significant improvement in photocatalytic degradation of the azo dye Rhodamine B under visible-light irradiation than TiO2 nanosheets, which could be attributed to the extending spectral response from UV to visible area, the enhanced photosensitizing effect of the surface enriched Bi2O3 quantum dots and the strong interaction between Bi2O3 and TiO2. Furthermore, the Bi2O3/TiO2/graphene hybrids could be used as a stable photocatalyst for the highest photocatalytic activity for Rhodamine B degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the heterostructures. This investigation likely opens up new possibilities for the development of highly efficient TiO2 based photocatalysts that utilize visible-light as an energy source. (C) 2012 Elsevier B.V. All rights reserved.

Noble metal modification has been demonstrated to be an efficient strategy to improve the photocatalytic performance of TaON photocatalysts. However, the previous studies about the noble metal modification are only restricted to the surface loading of metallic noble metal, investigations have seldom been focused on the simultaneously deposited and doped X/TaXzON (X = Pt, Ru) photocatalyst. In this work, single-phase Ta1-zXzO1+zN1-z (X = Pt, Ru, 0 < Z <= 0.001) (as TaXzON) and heterostructured X-delta/Ta1-z+delta Xz-delta O1+z-dN1-z+delta (X = Pt, Ru, 0.001 < Z <= 0.016) (as X-delta/TaXz-delta ON) photocatalysts were synthesized by a sol-gel method in combination with a post-treatment nitridation process. The chemical states and form of noble metals in the as-prepared TaXzON and X-delta/TaXz-delta ON samples were characterized by XPS and HRTEM. In a few noble metal doping sol-gel processes, the visible-light photocatalytic activity of single-phase TaPtzON (Z = 0.0005) and TaRuzON (Z = 0.0005) showed a rate of H-2 production at 51 and 90 mu mol h(-1) higher than that of the pristine TaON. With the increase of noble metal content, the photocatalytic activity of heterostructured Pt-delta/TaPtz-delta ON (Z = 0.004) and Ru-delta/TaRuz-delta ON (Z = 0.004) exhibited a rate of H-2 evolution at 198 and 258 mu mol h(-1) which was about 28 and 6 times than the TaON loaded noble metal by photodeposition, respectively. Moreover, further photodeposition of noble metal was performed at the heterostructured materials. It was found that the highest photocatalytic activity of the catalyst was achieved based on X-delta/TaXz-delta ON (X = Pt, Ru, Z = 0.002). This enhanced photocatalytic activity is mainly ascribed not only to the doping effect leading to formation of an isolated energy level contributing to more visible-light absorption but also to the well-distributed noble metal on the surface of the photocatalysts with strong interaction with TaON resulting in photoinduced interfacial charge transfer. This work may provide some insight into the smart design of novel and high-efficiency photocatalytic materials.

Amorphous matrices of three-dimensionally interconnected MnOx/MnOOH nano-spheres were electrochemically assembled onto a carbon substrate by a pulse galvanostatic method (PGM) in a nonionic reverse micelle electrolyte. The synthesized material showed a unique morphology which was attributed to a synergistic effect between the amphiphilic molecule based interface membrane as a soft template and the PGM approach. The transfer of the reactant was remarkably special because of the elusive thermodynamic and kinetic parameters of the interactions at the interface between the two different phases such as the polar phase-interface membrane, interface membrane-nonpolar phase and polar phase-electrode interactions. Further work involved investigations into the potential application of the assembled MnOx/MnOOH films as high performance supercapacitor electrode materials. The capacitive performance of the assembled MnOx/MnOOH was tested in a solution of 0.5 M Na2SO4. The highest specific discharge capacitance of 1659 F g(-1) was achieved at a current density of 2 A g(-1), and remained as high as 782 F g(-1) even at a very large current density of 10 A g(-1). The outstanding capacitance properties were ascribed to the ternary oxide composites forming highly porous nanostructures which guaranteed a large specific surface, full utilization of Mn oxides and a small amount of degradation of amorphous MnO2. The results indicate the feasibility of electrochemically synthesizing Mn oxides in unconventional micelle electrolytes, and their successful application in supercapacitors.

Studies were performed to investigate the cathodic behavior of silicon (IV) ion in a BaF2-CaF2-SiO2 melt at a temperature of 1573 K. The results obtained show that the silicon (IV) ion was reduced through a single-step from Si4+ + 4e = Si, which was an irreversible process with diffusion-controlled mass transfer. The diffusion coefficient (D) for the reduction process of silicon (IV) ion in BaF2-CaF2-SiO2 melt was 9.76 x 10(-5) cm(2) s(-1), at 1573 K. Furthermore, galvanostatic electrolysis performed on a molybdenum electrode, which further presents the feasibility of electro-depositing silicon in molten BaF2-CaF2-SiO2 system. (C) 2013 The Electrochemical Society. [DOI: 10.1149/2.038303jes] All rights reserved.

Single crystalline Na2Ti3O7 rods were prepared through sintering a precursor synthesized in a reverse micelle. Charge/discharge measurements were performed in the potential range 0.01-2.5 V versus Na/Na+ under different C-rates. The tested capacity was maintained at 103 mA h g(-1), even after 20 cycles at a rate of 0.1 C. The results exhibited that the as-prepared single crystalline Na(2)Ti(3)O7 rods had a very low voltage plateau (around 0.3 V), and were suitable to use as anode materials for sodium-ion batteries.

Highly efficient hydrogen production can be achieved by three-dimensional (3D) architectures of CdS quantum dots (QDs) incorporated in the porous assembly of marigold-like ZnIn2S4 heterostructures coupled with graphene, leading to an efficient electron transfer between them and the enhancement of the ZnIn2S4 photostability. The as-prepared samples were characterized by X-ray diffraction, electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance absorption spectra, and photoluminescence spectra. Especially, 3 wt% CdS QDs decorated ZnIn2S4 heteroarchitectures showed a high rate of H-2-production at 1.9 mmol h(-1), more 2.7 times than that of ZnIn2S4. The rate was further increased to 2.7 mmol h(-1) with a high quantum efficiency of 56% using the 3 wt% CdS QDs decorated ZnIn2S4 composites coupled with 1 wt% graphene (about 4 times higher than that of the pure ZnIn2S4). Moreover, the CdS QDs/graphene/ZnIn2S4 exhibited strong durability due to the high hydrothermal stability of the flower-like structure and the inhibition of CdS leaching owing to its strong interaction with ZnIn2S4. The excellent photocatalytic performance is ascribed to the enhanced light absorption and the improved separation of photogenerated carriers. This finding highlights the validity of 3D semiconductor heterostructures as effective building blocks for exploring efficient visible-light-active photocatalysts.

Si/PANI core/shell composite is simply synthesized by an in-situ chemical polymerization method. The images of the obtained Si/PANI composites show that an amorphous PANI layer is adsorbed evenly on the nano-Si surface with a thickness of about 6 nm, forming the Si/PANI core/shell structure. It is observed that the Si/PANI anodes display the well cycling stability at a high rate of 1 C with the cutoff potential window of 0.01 V and 1.5 V. The initial charge capacity is 2083.8 mAh g(-1), 1015.9 mAh g(-1) and 583.6 mAh g(-1) for the Si/PANI anodes containing 70 wt%, 50 wt% and 30 wt% PANI, respectively. Over 100 cycles, the capacity is kept at 889.6 mAh g(-1), 672.5 mAh g(-1) and 545.3 mAh g(-1) respectively. Furthermore, the reversible capacity of the Si/PANI anode containing 70 wt% PANI still maintains at 1087.8 mAh g(-1) even at the rates of 1 C, 0.5 C and 0.2 C after each 100 cycles. The results indicate that the PANI shell accommodates the large volume expansion and shrinkage of Si core during the lithium intercalation and extraction process, which facilitates the contact of electrode materials, thus ensures the higher discharge and charge capacity and better cycling stability. (C) 2013 The Electrochemical Society. All rights reserved.

Niobium nanoparticles with high purity were prepared by a sodiothermic reduction process using Nb2O5 as the raw material, LiCl, NaCl, KCl and CaCl2 as the diluents and sodium as the reducing reagent. The effects of the different molten salt systems, CaCl2 content, reaction time, excessive sodium and reaction temperature on the characteristics of the obtained niobium powder were discussed. The as-prepared niobium nanoparticles under the optimum experimental conditions were obtained by sodiothermic reduction with 20% excessive sodium in the NaCl-52mo1%CaCl2- 2mol%Nb2O5 molten salts at 650 degrees C for 6 h, and the molar ratio of the oxygen element in Nb2O5 and the CaCl2 of the molten salts is less than 19.23% at 750 degrees C. Moreover, the particle size of niobium nanoparticles is ranged about 40 similar to 240 nm with increasing of reaction temperature from 650 to 800 degrees C.

Photocatalytic oxygen evolution with a high efficiency was achieved using tantalum nitride (Ta3N5) quantum dots (QDs) coupled TaON hollow spheres (Ta3N5-TaON). TaON hollow spheres coupled with the surface enriched Ta3N5 QDs were prepared by an in situ chemical reduction route in ammonia solution at -45 degrees C and were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, UV-vis diffuse reflectance spectra and photoluminescence spectra. The Ta3N5-TaON composites containing 4 mol% Ta3N5 QDs showed a high rate of O-2 production at 208.2 mu mol h(-1) with an apparent quantum efficiency of 67% under 420 nm light. The rate of oxygen formation of the Ta3N5-TaON heterojunction was 3.3 times higher than that of the pristine TaON hollow spheres. Furthermore, relative photoelectrochemical properties of Ta3N5-TaON composite photoelectrodes were investigated. The resulting 4 mol% Ta3N5-TaON heterojunction films exhibited a photocurrent of ca. 2.7 mA cm(-2) under visible light irradiation at 1.0 V vs. SCE in Na2SO4 solution. This excellent photocatalytic activity is ascribed to the Ta3N5 QDs that alter the energy levels of the conduction and valence bands in the coupled semiconductor system and the slow recombination of photogenerated electron-hole pairs. Moreover, the Ta3N5-TaON composite exhibited strong durability which could be attributed to the inhibition of Ta3N5 QDs leaching owing to its strong interaction with TaON.

Tantalum nitride nanoparticles, as visible-light photocatalysts were synthesized by a two-step homogeneously chemical reduction without any polymers and templates. The well-crystallized Ta3N5 nanoparticles with a range of 20-50 nm in size have been characterized by a number of techniques, such as XRD, XPS, SEM, TEM, BET and UV-Vis spectrum. Most importantly, the Ta3N5 nanoparticles with good stability exhibited higher photooxidation activities in the water splitting and degradation of methylene blue under visible light irradiation than bulk Ta3N5 particles and commercial P25 TiO2, demonstrating that Ta3N5 nanoparticle is a promising candidate as a visible-light photocatalyst. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.

High-efficiency Si@TiN composite anode was synthesized by a homogeneous reduction reaction in the liquid ammonia, then calcinated at 950 C for 2 h in vacuum. The crystal structure and morphology of the obtained in-situ coated composites were characterized by XRD, FESEM. The results showed that the micron-sized Si particles were almost coated by the TiN nanoparticles with the average size of 50 nm, while the morphology of Si@TiN composite was almost unchanged over 50 discharge-charge cycles. The electrochemical performances of Si@TiN composite anode were studied by galvanostatic discharge-charge tests, cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The CV curves showed that the two redox peaks remained stable and were attributed to the alloying/dealloying process of Li with active Si particles. It could be seen from the EIS curves that the charge transfer resistance (R-ct) for fresh was larger than that for the 50th cycle, which was mainly because the electrons and Li ions conducted on the electrode surface more difficultly for fresh. The cycle stability of the as-prepared Si@TiN composite anode was investigated, with the result showing that the cycling performance was stable and optimal at a rate of 0.2 C. The initial charge capacity was as high as 3226.99 mAh g(-1), which was kept as 467.02 mAh g(-1) over 50 cycles. (c) 2012 Elsevier B.V. All rights reserved.

Titanium oxycarbide was synthesized through carbothermic reduction of TiO2 and sintering of TiO and TiC. The combustion enthalpy and specific heat capacity of oxycarbide were measured by differential scanning calorimetry (DSC). The mixing enthalpy and Gibbs free energy of the reaction 0.5TiO + 0.5TiC = TiC0.5O0.5, consequently, was calculated based on the preceding measured data. The Gibbs free energy obtained was in good agreement with those results obtained by the equilibrium measurements.

The influence of oxygen content and heat treatment on the evolution of carbides in a powder metallurgy (PM) Ni-base superalloy was characterized. The results reveal that oxygen content has little influence on the precipitation of carbides inside the particles. However, under the consolidated state, stable Ti oxides on the particle surface act as nuclei for the precipitation of prior particle boundaries (PPB). Also, oxygen can diffuse internally along grain boundaries under compressive stress, which favors the precipitation of carbides inside the particles. Therefore, a higher amount of carbides will appear with more oxygen content in the case of consolidated alloys. It is also observed that PPB can be disrupted into discontinuous particles at 1200 inverted perpendicular C, but this carbide network is hard to be eliminated completely. The combined MC-M23C6 morphology approves the nucleation and growth mechanism of carbide evolution.

TiN coated SiC particles were prepared by the method of controlled hydrolysis and subsequent nitridation with NH3 gas. The coated composite powder was consolidated by spark plasma sintering. The main focus was thermo-physical and brazing properties of (SiC)(TiN)/Cu composites. The results indicate that controlled hydrolysis combined with nitridation is a suitable technique to produce TiN coated SiC particles. TiN film is thin and continuous, which is favorable to improve densification and enhance interfacial bonding between the reinforcement and the matrix. CTE of (SiC)(TiN)/Cu composites ranges between 8.1x10(-6)similar to 11.9x10(-6) K-1 and decreased with increasing SiC content. Thermal hysteresis phenomenon emerged during the thermal cycling and the residual plastic strain reaches 4.0x10(-4) after 8 cycles. The highest thermal conductivity is 270 W.m(-1).K-1 for the composites containing 30vol% SiC. It is found that (SiC)(TiN)/Cu composites show excellent compatibility with Ag-Cu-Ti and the solder can spread completely on the substrate at 900 degrees C. The highest shear strength reaches 56 MPa. Additionally, excessive high temperature and excessive long holding time are detrimental to the joining strength due to the aggregation of the interfacial reaction.

The polycrystalline TiO2@TiC0.5-xO0.5+x ceramics with core-shell structure were prepared through the spark plasma sintering process. Both thermoelectric (TE) transport properties and microstructure of the ceramics were investigated. The TiO2 shell had a remarkable effect on the transport properties of the system. Large electrical conductivity and thermopower was observed in coating 15% TiO2@TiC0.5O0.5 sample. The maximum power factor is 8.1 x 10(-4) W m(-1) K-2 and the corresponding ZT value is 0.3 at 873 K for 15% TiO2@TiC0.5O0.5. (C) 2012 Elsevier B.V. All rights reserved.

Using the spark plasma sintering process In2-xCexO3 (0 = x = 0.10) fine grained ceramics have been synthesized. Our results indicate that all the In2O3-based ceramic samples show good electrical conductivity and high thermoelectric power factor. In comparison with pure In2O3 bulks or doped samples with grain size above 1 mu m, the 100300 nm fine grain In2O3-based ceramics exhibit much lower thermal conductivities (1.92.5 W center dot(m center dot K)-1 at 1173 K), demonstrating a remarkable cooperative tuning effect imposed by grain size reduction and nano-clusters formation. The maximum figure of merit ZT value is optimized up to 0.47 at 1223 K for In1.92Ce0.08O3 sample, which makes them promising candidates for thermoelectric applications.

Titanium oxycarbide (TiCxOy) was successfully prepared by an electro-deoxidation of TiO2/C composite cathode in molten calcium chloride at 900 degrees C. The composite cathode was prepared by adding an amount of carbon into TiO2 powders. By using X-rays diffraction and scanning electron microscopy, it was found that the presence of carbon resulted in changes in reaction mechanism and accelerated the rate of electrochemical reaction. The results suggested that the electrochemical reduction of TiO2/C composite was the following: firstly titanium dioxide was reduced to TiOn (0 < n < 1) along with the formation of CaTiO3. Then, TiOn (0 < n < 1) reacted with carbon to TiCxOy. (C) 2012 Elsevier Ltd. All rights reserved.

Tantalum nitrides (TaNx) nanocrystals with different phase and morphology have been synthesized through homogenous sodium reduction under low temperature with the subsequent annealing process under high vacuum. The crystal structures of tantalum nitrides were determined by Rietveld refinement based on the X-ray diffraction data. The morphologies of various tantalum nitrides nanocrystals in high quality were analyzed through the electron microcopies examinations. The spherical TaN nanoparticles, cuboidal TaN0.83 and TaN0.5 nanocrystals have been selectively prepared at different annealing temperatures. In addition, the specific surface areas of the tantalum nitrides nanocrystals measured by BET method were around 9.87-11.64 m(2) g(-1), indicating that such nano-sized tantalum nitrides could be suitable for capacitor with high specific capacitance. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

Nb5Si3 intermetallic compound was directly synthesized via an electrodeoxidation process from molten CaCl2 electrolyte. The reaction mechanism was studied by performing a series of quenching investigations, which suggested that the formation of a series of sub oxides and compounds containing calcium and oxygen preceded the formation of Nb5Si3. While Nb2O5 was gradually reduced to its sub oxides, (Nb2O5/NbO2/NbO/Nb), SiO2, on the other hand, got directly reduced to silicon and reacted with Nb to form Nb5Si3. (c) 2012 Elsevier Ltd. All rights reserved.

This work revealed that BiCuSeO oxyselenide is a potential oxide-based thermoelectric material, whose dimensionless figure of merit (ZT) reaches similar to 0.70 at 773 K. High phase-purity BiCuSeO polycrystalline materials with fine grains were synthesized by a facile method combining a solid-state reaction and spark plasma sintering. Purifying the constitutive phase and reducing the grain sizes by introducing a high-energy ball milling process before spark plasma sintering were found to be effective in property enhancement. The resultant single-phased BiCuSeO sample derived from ball-milled powders shows good electrical conductivity above 4.0 x 10(3) S m(-1) and a large Seebeck coefficient above 200 mu V K-1. This compound has a low thermal conductivity (similar to 0.5 W m(-1) K-1), which is associated with its low phonon transport speed and Young's modulus. Results indicated that BiCuSeO-based materials are promising for energy conversion applications in the moderate temperature range.

Nitrogen doped bismuth niobate (N-Bi3NbO7) hierarchical architectures were synthesized via a facile two-step hydrothermal process. XRD patterns revealed that the defect fluorite-type crystal structure of Bi3NbO7 remained intact upon nitrogen doping. Electron microscopy showed the N-Bi3NbO7 architecture has a unique peony-like spherical superstructure composed of numerous nanosheets. UV-vis spectra indicated that nitrogen doping in the compound results in a red-shift of the absorption edge from 450 nm to 470 nm. XPS indicated that [Bi/Nb]-N bonds were formed by inducing nitrogen to replace a small amount of oxygen in Bi3NbO7-xNx, which is explained by electronic structure calculations including energy band and density of states. Based on observations of architectures formation, a possible growth mechanism was proposed to explain the transformation of polyhedral-like nanoparticles to peony-like microflowers via an Ostwald riping mechanism followed by self-assembly. The N-Bi3NbO7 architectures due to the large specific surface area and nitrogen doping exhibited higher photocatalytic activities in the decomposition of organic pollutant under visible-light irradiation than Bi3NbO7 nanoparticles. Furthermore, an enhanced photocatalytic performance was also observed for Ag/N-Bi3NbO7 architectures, which can be attributed to the synergetic effects between noble metal and semiconductor component. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Nanoparticles of the Li-Ti-O precursors have been prepared using a reverse micelle method. Transmission electron microscopy (TEM) analysis showed that the precursor had an amorphous structure. The average diameter of the amorphous Li-Ti-O particles was approximately 5 nm (within a range of +/- 2 nm). X-ray diffraction measurement (XRD) results showed that the conversion of the amorphous precursor to crystalline spinel Li4Ti5O12 occurred upon a heat treatment at 450 degrees C in an atmosphere. This is much lower than that for a standard solid-state reaction of Li2CO3 and TiO2. An interesting result was that the spinel Li4Ti5O12 synthesized at 450 degrees C, with a particle size of 10-20 nm, had a good pseudocapacitor performance. The charge/discharge testing indicated that the specific capacity, using the activated material of the spinel Li4Ti5O12 synthesized at 450 degrees C, still remained 91 mAh g(-1) even at a high charge/discharge rate of 40C after 100 cycles. In comparison, the Li4Ti5O12 particles synthesized at 650 degrees C have been grown to be the size of 50-60 nm, which mostly indicated a battery performance with a remaining specific capacity of 116 mAh g(-1) at a charge/discharge rate of 40C over 100 cycles. The significance in this work disclosed that the nanostructured Li4Ti5O12 prepared as a reverse micelle could be a bridging material between pseudocapacitor and lithium ion battery. (C) 2012 Elsevier Ltd. All rights reserved.

The separation and control of undesired elements are key to recycling scrap or end-of-life (EoL) metal products, as the quality of regenerated metals is often impaired by contamination from the alloying elements in the scrap. However, little is known of their removability or controllability because they are normally absent in the production of primary metal from natural ore. Here, the distribution ratios of 31 kinds of alloying element among the metal, slag, and gas phases in the re-melting of EoL titanium products were quantitatively discussed. Our results clarified that the typical titanium alloying elements - Al, Fe, and V - are essentially uncontrollable in re-melted titanium by oxidation or evaporation. This suggests that the mixing of commercially pure titanium (CP-Ti) and other titanium alloys should be avoided. Hence, the development of new technologies to separate alloying elements from titanium scraps for sustainable titanium recycling is highly anticipated. (C) 2012 Elsevier B.V. All rights reserved.

This work proposed a process to prepare titanium subchlorides by using titanium and titanium tetrachloride as raw materials in an equimolar ratio of KCl-NaCl melt. According to the reactions Ti4+ +Ti -> 2Ti(2+), different molar ratio of Ti2+ /Ti3+ titanium subchlordie salts could be prepared by controlling the ratio of raw materials. And the concentration of Ti2+ can be measured by the molar mass of hydrogen based on the reaction, Ti2+ +H+.,reversible arrow Ti3++1/2H(3). The total titanium chloride concentration was measured by the Diantipyryl Methane Photometric method. The prepared titanium subchloride was used as electro-activation ions for the titanium deposits in KCl-NaCl melts at 720 degrees C.

Co-base ODS alloys, strengthened by nanosized oxide dispersion and gamma' precipitates, were prepared by mechanical alloying. Hot compression tests were performed in the temperature range of 25-970 degrees C with the strain rate varying from 0.0001 to 0.01 s(-1). The influence of deformation parameters and Y2O3 content on the flow behavior and the microstructure of compressive specimens were investigated. It was observed that Co-base ODS alloys had exhibited the homogeneous distribution of ultrafine gamma' precipitates (0.26 mu m), nanosized oxide particle (12.5 nm), and small grains (1.1 mu m). The enhanced flow stress at low temperatures and high strain rates was attributed to the rapid multiplication of dislocations due to the pining effect of oxide dispersion, gamma' precipitates, and fine grains. The peak stress had decreased with increasing the deformation temperature as well as by decreasing the strain rate. The obvious improvement in flow stress was acquired by increasing the Y2O3 contents. Grain boundary sliding and porosity growth had been considered to be the main softening mechanisms during the hot deformation at elevated temperature. Moreover, It was found that the flow softening could be accelerated by decreasing the strain rate. The activation energy had increased with increasing temperature, but decreased with decreasing strain rate. (C) 2011 Elsevier B. V. All rights reserved.

Garlic peel was used as the raw material to synthesize the biosorbent for the selective recovery of precious metals from the acid chloride solution. Garlic peel is rich in carboxyl-, amino-and thiol-groups, has the potential of exhibiting high affinity to Au(III) when appropriate chemical modification process was employed. Here in the present study, the biosorbent was prepared by cross-linking garlic peel particles with concentrated sulfuric acid. Adsorption tests for mixing different metal ions such as Au(III), Fe(III), Cu(U), Ni(II) and Zn(II) from various concentrations of hydrochloric acid media indicated that Au(IIl) was selectively adsorbed on the cross-linked garlic peel gel over the other coexisting base metal ions investigated. The crosslinking mechanism and selective adsorption of Au(IIl) were also investigated briefly.

Highly porous nanorod-PANI-Graphene composite films were prepared by in situ electrochemical polymerization onto an ITO substrate in a reverse micelle electrolyte. The morphology and microstructure of the composite films were analyzed by using a field emission scanning electron microscope. It was observed that the films were highly porous and the nanorod PANI films were inserted by graphene nanosheets. This indicated that a good conductive network between PANI nanorods and graphene sheets was formed. Further electrochemical tests involved cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) in 1 mol L-1 HClO4 solution. The results showed that the composite film had a favorable capacitance with a high electron transfer rate and low resistance. The highest specific capacitance that could be achieved was as high as 878.57 F g(-1) with the charge loading of 500 mC at a current density of 1 A g(-1). The GCD at different charge loadings showed good cycle stability with a low fading rate of specific capacitance after 1000 cycles. The results demonstrated that the nanorod-PANI-Graphene composite was proved to be of great potential as an electrode material for supercapacitors.

Large-scale hydrogen production through water splitting using photocatalysts with solar energy can potentially produce clean fuel from renewable resources. In this work, photocatalytic evolution of H-2 with a high efficiency was achieved using graphene oxide (GO) nanosheets decorated with CdS sensitized TaON core-shell composites (GO-CdS@TaON). The CdS@TaON core-shell nanocomposites were prepared by an ion-exchange route with assistance from a hydrothermal process on GO as the support. The TaON core-shell composites containing 1 wt% CdS nanocrystals showed a high rate of H-2-production at 306 mu mol h(-1) with an apparent quantum efficiency (QE) of 15% under 420 nm monochromatic light. The rate of hydrogen formation was 68 times faster in comparison with the rate observed on pure TaON. The rate was further increased to 633 mu mol h(-1) with a high quantum efficiency of 31% when the GO-CdS@TaON hybrid composite was coupled with 1 wt% of graphene oxide and 0.4 wt% of Pt (about 141 times higher than that of the pristine TaON). This high photocatalytic H-2-production activity is ascribed firstly to the presence of CdS nanocrystals that alter the energy levels of the conduction and valence bands in the coupled semiconductor system; secondly to the involvement of graphene oxide that serves as an electron collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers from CdS@TaON composites. This investigation can open up new possibilities for the development of highly efficient TaON-based photocatalysts that utilize visible light as an energy source.

The Bi2O3 quantum dots decorated nitrogen doped Bi3NbO7 nanosheets (Bi2O3/N-Bi3NbO7) were successfully synthesized via a facile in situ hydrothermal process as a straightforward protocol. The peony-like N-Bi3NbO7 hierarchical architectures decorated with surface enrichment of Bi2O3 quantum dots were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, UV-vis diffuse reflectance spectrum and photoluminescence spectra. The as-prepared Bi2O3/N-Bi3NbO7 heterostructures exhibited higher photocatalytic activities in the decomposition of model pollutants under visible-light irradiation than N-Bi3NbO7 nanosheets in the absence of any expensive metal components and co-catalysts, which could be attributed to the enhanced light absorbance multiple reflections in the heterostructures, the enhanced photosensitizing effect of the surface enriched Bi2O3 quantum dots and the strong interaction between Bi2O3 and N-Bi3NbO7. Furthermore, the Bi2O3/N-Bi3NbO7 heterostructures exhibited strong durability that may be ascribed to the high hydrothermal stability of the flower-like structure and the inhibition of Bi2O3 leaching owing to its tight chemical bonding with N-Bi3NbO7 nanosheets.

Large-scale hydrogen production through water splitting using photocatalysts with solar energy can potentially produce clean fuel from renewable resources. In this work, photocatalytic hydrogen evolution with a high efficiency was achieved using CdS nanocrystal decorated CdLa2S4 microspheres (CdS/CdLa2S4) successfully prepared by a two-step hydrothermal process. The obtained CdS/CdLa2S4 composite was characterized by X-ray diffraction (XRD), electron microscopy (EM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance absorption spectroscopy (DRS), and photoluminescence spectroscopy (PL). XRD demonstrated that highly crystalline hexagonal CdS was obtained in CdS/CdLa2S4. EM results revealed that CdLa2S4 microspheres assembled from a large number of nanoprisms, were intimately enwrapped by the surrounding CdS nanocrystals with a particle size below 20 nm. This unique architecture resulted in the appropriate dispersion of CdS nanocrystals and intimate multipoint contacts between the CdS nanocrystals and CdLa2S4, which led to significant enhancement of charge separation in CdS/CdLa2S4. Especially, the CdLa2S4 microspheres decorated with 3 wt% CdS nanocrystals containing 0.4 wt% of Pt showed a high rate of H-2-production at 2.25 mmol h(-1) with an apparent quantum efficiency of 54% under 420 nm monochromatic light. The rate of hydrogen evolution from water splitting was 9 times faster in comparison with the rate observed on pure CdLa2S4, which is ascribed to the presence of CdS nanocrystals that alter the energy levels of the conduction and valence bands in the coupled semiconductor system.

The equilibrium between titanium ions and metal titanium was investigated in fluoride-chloride molten salt. The electrochemical properties of titanium ions in fluoride-chloride were studied on a molybdenum electrode by cyclic voltammetry (CV) and square wave voltammetry (SWV). The equilibrium constant of the equilibrium between titanium ions and metal Ti was calculated in KCI-NaCl- 2.5wt %K2TiF6 at the temperature of 1073K.

Watermelon peel is selected as a novel adsorbent to remove Pb(II) from aqueous solution. A simple saponification process is proposed to modify the peel and the adsorbent is characterized by SEM and FTIR. The effects of pH, contact time, initial concentration of Pb(II), biosorbent dosage and temperature on adsorption of Pb(II) are investigated. Different models are used to fit experimental data. These models indicate that the adsorption process follows the Langmuir model and pseudo-second-order model. The maximum adsorption capacity obtained from Langmuir model is l. OSmol kg(-1) for the prepared sorbent. Equilibrium time is attained in 5-10 min for the studied concentrations. The watermelon peel can be used as an effective and low-cost biosorbent for removal of Pb(II) from aqueous solution.

Na2NbAlO5 was synthesized using Nb2O5 and NaAlO2 as raw materials in molten NaCl-CaCl2 by a solid reaction. With an addition of sodium into the melts, Na2NbAlO5 was subsequently reduced to form NbAl3 intermetallic compound with a particle size of 50-300nm.

The behavior of electrochemically depositing silicon in a molten high-melting-point fluoride electrolyte was studied at 1300 degrees C. The cathodic product was characterized by XRD, SEM and EDS. Though the analysis of structure and composition of deposition, it could certify that silicon deposited on the Mo rod and alloyed with molybdenum. A series of tests had been performed on the cathodic behavior of Si4+ ions in BaF2-CaF2-Na2SiF6 molten salt. The influence of electrochemical parameters on the cathodic deposition of silicon was also investigated. The electrochemical behavior of Si4+ ions in applied fluoride melts was observed to proceed according to one-step reaction.

Poplar cotton, a cellulosic material, was found to adsorb metals ions effectively. In the present study, the biosorption characteristics of Pb(II) onto poplar cotton, were evaluated as a function of pH, contact time, biomass dosage, initial concentration and temperature. Within the pH range investigated (1.0-6.0), the optimal pH value suitable for the uptake of Pb(II) was determined. The maximum adsorption capacity obtained from the Langmuir model is around 0.52mol kg(-1) for the poplar cotton sorbent. Equilibration is achieved in 60min for the studied concentrations. Results suggest that the poplar cotton can be directly used as an effective and low-cost biosorbent for removal of Pb(II) from aqueous solution.

Silicon and silicon carbide mixing micropowders obtained from the saw cutting industry of polycrystalline silicon ingot is separated by a simple sequential sedimentation. The Zeta potentials of the powders in the aqueous suspension are adjusted by varying the pHs with dilute acid or alkaline reagents. The dispersion and aggregation content of the microparticles is significantly influenced by pHs, and so their settlement velocity in the same hydraulic conditions are quite different, and silicon powders tend to suspend in the upper section of the suspension for its finer size and smaller density under the stronger Zeta potential repulsion force. The original content of the cutting powders with 30%wt silicon are separated into the Si-rich and SiC-rich powder respectively, and 62% wt Si-rich powder can be obtained after 4 times of sedimentation under pH = 8.0, showing the great potential for Si and SiC powder separation and recovery in a cost-effective way.

Core-shell TaNx nanocomposites were prepared through the in-situ coating process on the basis of synthesis of TaN0.5 nanoparticles. The X-ray diffraction results showed the nanocomposites consisted of TaN and TaN0.5 crystalline phase. TEM and SEM images demonstrated that TaN nanopowders as a coating layer grew on the surface of TaN0.5 nanoparticles, producing TaNx nanocomposites with core-shell structure. The specific surface area of nanocomposite powders was as large as 4.87 m(2)g(-1)-6.13 m(2)g(-1), indicating that such TaNx nanocomposites exhibited great potential of application to the capacitor with ultra high specific capacitance.

The quality of titanium depends largely on the morphology of titanium deposit, which can be affected by electrokinetic parameters during the electrolysis. To obtain titanium deposit, titanium dichloride was prepared successfully by using a titanium sponge to reduce titanium tetrachloride in NaCl-KCl. Electroanalytical methods including cyclic voltammetry, chronopotentiometry, and square wave voltammetry were employed to investigate the cathodic behavior of Ti2 + . The results proved that the reduction of Ti(II) proceeds in a one-step, diffusion-controlled process. A series of the tests were carried out to investigate the influence of electrokinetic parameters on the titanium deposit morphology. It was concluded that the deposit titanium grain size increases with increasing titanium ion concentration. In the system with a high titanium ion concentration, the grain size also increases with increasing the current density until a certain value. However, a subsequent increase of current density results in the formation of dendrites. It was found that stirring was an effective way to avoid dendrite. A compact deposit with large grains was obtained by the electrolysis with the stirring of argon injection.

A significant enhancement of thermoelectric performance in layered oxyselenides BiCuSeO was achieved. The electrical conductivity and Seebeck coefficient of BiCu1-xSeO (x = 0-0.1) indicate that the carriers were introduced in the (Cu2Se2)(2-) layer by Cu deficiencies. The maximum of electrical conductivity is 3 x 10(3) S m(-1) for Bicu(0.975)Seo at 650 degrees C, much larger than 470 S m(-1) for pristine BiCuSeO. Featured with very low thermal conductivity (similar to 0.5 W m(-1) K-1) and a large Seebeck coefficient (+273 mu V K-1), ZT at 650 degrees C is significantly increased from 0.50 for pristine BiCuSeO to 0.81 for BiCu0.975SeO by introducing Cu deficiencies, which makes it a promising candidate for medium temperature thermoelectric applications.

Highly crystalline bismuth titanate (Bi(12)TiO(20), BiT) nanorods, as visible-light photocatalysts were prepared by a template-free hydrothermal process. The as-prepared BiT nanorods fabricated in high yields by simply manipulating pH values in the absence of any capping agent, were characterized by a number of techniques, such as XRD, SEM, TEM, HRTEM, BET, and UV-Vis spectrum. In this case, hydroxide ions seem to play a pivotal role in controlling the formation of seeds and the growth of the BiT nanorods. Based on the structural analysis of nanocrystals obtained at different pH values, we proposed a plausible mechanism to account for the formation of the tunable morphologies. Most importantly, the BiT nanorods with good stability exhibited higher photocatalytic activities in the degradation of Rhodamine B under visible light irradiation (lambda a parts per thousand yen 420 nm) than the commercial P25 TiO(2) and bulk BiT powders, demonstrating that Bi(12)TiO(20) is a promising candidate as a visible-light photocatalyst.

Garlic peel, as the raw material, was modified by loading with zirconium(IV), exhibiting quite good uptaking behaviour for fluoride anion. The adsorption experiments were carried out in batch shaking vessels, and the process was strongly dependent on the pH value. The adsorption fits Langmuir model well, and the maximum adsorption capacities at equilibrium pH 2 and 6 are evaluated to be 1.10 and 0.89 mol(fluoride)/kg of Zr-loaded garlic peel gel, respectively. The evaluation of effects of coexisting anions such as nitrate, sulfate and phosphate shows that nitrate and sulfate have no negative effect on the adsorption of fluoride, while phosphate has a little effect. Adsorption kinetics of fluoride is well described by pseudo-second-order rate equation, and the corresponding adsorption rate constant is calculated to be 3.25x10(-3) g/(mg center dot min).

A three-dimensional (3D) multicomponent oxide, Bi12TiO20/TiO2 hierarchical heterostructure was successfully synthesized via a one-step and template-free hydrothermal route. X-ray diffraction and X-ray photoelectron spectroscopy measurements confirm that the composition of the as-fabricated sample is Bi12TiO20/TiO2 composite. Scanning and transmission electron microscopy observation reveals that the as-synthesized sample is microsized flower-like hierarchical networks consisted of Bi12TiO20 nanorods decorated with the primary TiO2 nanoparticles. Extension of the light absorption from the ultraviolet region to the visible-light region was confirmed by UV-vis absorption spectra. Due to the structure-property relationships, the 3D Bi12TiO20/TiO2 heterostructure exhibited enhanced visible photocatalytic activity over that of Bi12TiO20 and TiO2 samples in the decomposition of Rhodamine B in water which is a typical model pollutant. The enhanced photocatalytic activity can be attributed to the extended absorption in the visible light region resulting from the 3D Bi12TiO20/TiO2 heterostructures. and the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the Bi12TiO20/TiO2 junction interface, demonstrating that the Bi12TiO20/TiO2 heterostructure is a promising candidate as a visible light photocatalyst. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Nano-sized polyaniline (PANI) films were electrochemically deposited onto an ITO substrate by a pulse galvanostatic method (PGM) in an aqueous solution. The morphology of the as-prepared PANI film was characterized using a field emission scanning electron microscope (FESEM). It was observed that the as-prepared PANI films were highly porous, and showed a nano-sized rod-like or coralline-like morphology depending on the charge loading performed in the electropolymerization process. Furthermore, the PANI films were electrochemically measured by the galvanostatic charge-discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests in 1 mol L(-1) HClO(4) solution. The results showed that such PANI films had a favorable electrochemical activity and an excellent capacitance. The rod-like PANI film prepared with the charge loading of 1000 mC showed the highest discharge capacitance of 569.1 F g(-1) at a low current density of 1 A g(-1). The discharge capacitance retained 97.7% after 1000 cycles at a large current density of 10 A g(-1). (C) 2011 Elsevier B.V. All rights reserved.

A CsCl-based melt, was used as a supporting electrolyte fora fuel cycle in pyrochemical separation, as it has a high solubility for lanthanide oxide. Cyclic voltammetry and square wave voltammetry were carried out to investigate the cathodic reduction of those rare earth ions. The results prove that the cathodic process of La(III) ions dissolved in a CsCl-based melt, with a one-step reduction La(3+)+3e(-) = La, and is similar to those of other reports which have utilised LiCl-KCl or CaCl(2)-KCl molten salt systems. However, for the Ce(III) ions that dissolved in a CsCl-based melt, there is a significant difference when compared with published literature as there are two reduction steps instead of the reported single step Ce(3+)+e(-) =Ce(2+) and Ce(2+)+2e(-) = Ce. In order to explain the novel result, a detailed investigation was focused on the cathodic process of Ce(III) in a CsCl-based melt. The identification of the M-O (M = La, Ce) compounds that are stable in the electrolyte, as well as the determination of their solubility products, were carried Out by potentiometric titration using an oxide ion sensor. Furthermore, the E-pO(2-) (potential-oxide ion) diagram for the M-O stable compound was constructed by combining both theoretical and experimental data. (C) 2011 Elsevier B.V. All rights reserved.

Bi12TiO20 complex architectures (BiT) with flower-, spindle- and jujube-like shapes, were prepared through a facile template-free hydrothermal process, by controlling the reaction parameters, such as temperature, reagent concentration, and reaction time. Within the hydrothermal temperature range from 150 to 200 degrees C, the morphology transformed progressively from microjujube to microflowers consisted with nanospindles. A possible growth mechanism for BiT architectures was proposed to explain the transformation of nanoparticles to microflowers via an Ostwald ripening mechanism followed by self-assembly. Most importantly, much higher photocatalytic activities of BiT spindle-like structures modified with 0.5% polyaniline (PANI) via a simple chemisorption approach in comparison with unmodified BIT were obtained for the degradation of Rhodamine B (RhB) solution under visible-light irradiation (lambda > 420 nm). Furthermore, an enhanced photocatalytic performance for RhB degradation was also observed with the assistance of a small amount of H2O2. The reason could be ascribed to the synergic effect between PANI and BIT, which promoted the migration efficiency of photogenerated electron-hole on the interface of PAN! and BIT, demonstrating that PANI/BiT architecture is a promising candidate as a visible light photocatalyst. (C) 2011 Elsevier B.V. All rights reserved.

Polycrystalline In2O3 ceramics co-doped with Zn and Nd were prepared by the spark plasma sintering (SPS) process, and microstructure and thermoelectric (TE) transport properties of the ceramics were investigated. Our results indicate that co-doping with Zn2+ and Nd3+ shows a remarkable effect on the transport properties of In2O3-based ceramics. Large electrical conductivity (similar to 130 S cm(-1)) and thermopower (similar to 220 mu V K-1) can be observed in these In2O3-based ceramic samples. The maximum power factor (PF) reaches 5.3 x 10(-4) W m(-1) K-2 at 973 K in the In1.92Nd0.04Zn0.04O3 sample, with a highest ZT of similar to 0.25.

Carbon-modified bismuth titanate (C-Bi12TiO20) nanorods as visible-light-driven photocatalysts were synthesized via a facile hydrothermal process in the presence of glucose followed by the calcinations in Ar gas at 500 degrees C. The morphology, crystallinity of Bi12TiO20, and the nature of carbon in the composites obtained with different glucose amounts were characterized. Electron microscopy results, light absorption of C-Bi12TiO20 at wavelengths longer than 485 nm and X-ray photoelectron spectra clearly confirmed the carbon modification. Further results indicated that glucose did not affect the final crystalline structure or the band gap of Bi12TiO20, but it had great influence on the photocatalytic activity of Bi12TiO20 towards rhodamine-B (RhB) degradation. It was found that the appropriate amount of carbon can significantly facilitate the separation of photogenerated electron-holes and enhance the photocatalytic degradation efficiency. Especially, the C-Bi12TiO20 photocatalyst using 0.05 g glucose as carbon source can totally decompose RhB after 120 min irradiation. All results demonstrated that this work provides an alternate way to improve the photoactivity of Bi12TiO20 nanomaterial that is promising as a visible-light-driven photocatalyst.

In this study, the dissolution kinetics of silicon from sintering red mud in pure water was investigated. Experimental factors such as particle size and stirring speeds were studied to test their effect on the extraction fraction of silicon from red mud. It was found that the silicon extraction increases with stirring speed and decreasing in the particle size of red mud. Based on the experimental results, the Noyes-Whitney equation was adopted to describe and explain the dissolution behavior of the red mud in pure water, and the experimental data fit the model quite well in the whole process of dissolution.

Niobium aluminides were directly synthesized by a sodiothermic reduction process of NbCl5 - AlCl3 which was dispersed into LiCl - KCl - NaCl - CaCl2 melts. The melt supplied a homogenous reaction medium which was substantially beneficial to the co-reduction of Nb and Al to form niobium aluminides in situ. The reduction was performed at 500 degrees C for 4 hours. The products were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The corresponding results indicated that niobium aluminides powders were successfully synthesized.

The dissolution kinetics of steelmaking slag in pure water was studied, and the relative influential factors were investigated. The dissolution behavior of slag particles in water was well described by Noyes-Whitney equation, and for this kind of sparingly soluble rigid mineral this simple model was extensively applicable to describe their dissolution process. Experimental data were also obtained to confirm the significant promotion effect on the growth of some algae.

Tantalum nitrides (TaNx) nanoparticles with different crystal phase and various morphology were synthesized through low temperature homogenous sodium reduction route with the subsequent assistance of heat-treatment process. X-ray diffraction and TEM results demonstrated that the tantalum nitrides had the morphology of sphere, rectangle or square with the average particle size below 100nm. The specific surface area of the tantalum nitrides powders measured by BET was around 9.87-13.49m(2).g(-1), which indicated such nano-sized tantalum nitrides are the promising candidate for capacitor with high specific capacitance.

Tantalum nitride (Ta3N5) nanoparticles as a visible light photocatalytst were prepared by nitriding the amorphous tantalum nitride naoparticles under ammonia atmosphere at 1073 K. The production of well-crystallized Ta3N5 nanoparticles have primary particles 40-60 nm in size and a broad absorption band in the vicinity of 600 nm. The as-synthesized materials exhibit good activity for H-2 and O-2 evolution from pure water under visible light irradiation (lambda >= 420nm).

TiCxO1-x solid solutions were synthesized by sintering a mixture of titanium carbide and titanium monoxide at 1600 degrees C. The corresponding structures and morphologies of the TiCxO1-x solid solutions were characterized by XRD and SEM. A series of tests has been performed on the electrochemical dissolution behavior of TiCxO1-x solid solutions in NaCl-KCl molten salt. The influences of synthesis time and electrokinetic parameters on the anodic dissolution behavior were also investigated. The results showed that TiCxO1-x solid solutions can dissolve as Tin+ into alkali chloride melt. Titanium ion species dissolved from TiCxO1-x solid solutions changes between Ti2+ and Ti3+ depending on the applied potential. The tail gas on the anode was monitored by a mass spectrometer. It was found the synthesis time significantly affects the components of the anodic gas.

Single-crystalline chromium doped bismuth titanate (Bi(4)Ti(3-x)Cr(x)O(12), x = 0.0-0.5) nanosheets with exposed {110} facets have been synthesized via a facile hydrothermal process. The Bi(4)Ti(3-x)Cr(x)O(12) nanosheets possess well-defined tetragonal shapes with landscape dimension of 100-300 nm and thickness of 10-30 nm. The in-plane surfaces of the nanosheets lies on {001}, and the side surfaces are (110) and ((1) over bar 10). Extension of the light absorption from the ultraviolet region to the visible-light region arises from the Cr 2p levels confirmed by XPS spectra. The Bi(4)Ti(2.6)Cr(0.4)O(12) nanosheets with high stability showed the highest photocatalytic performance of H(2) evolution from water under visible-light irradiation. Furthermore, the heterostructures by using the NiO(x) nanoparticles tightly coupled on the surface of Bi(4)Ti(2.6)Cr(0.4)O(12) nanosheets, exhibited an enhanced photocatalytic activity due to the decrease in the recombination rate of the photoinduced electrons and holes, demonstrating that NiO(x)/Bi(4)Ti(2.6)Cr(0.4)O(12) nanosheet is a promising candidate as a visible light photocatalyst.

TaON modified by polyaniline (PANI), was prepared through a facile chemisorption process. PANI-modified TaON composites with good stabilities exhibit significantly higher photocatalytic activities than that of neat TaON on degradation of RhB under visible light irradiation, which may result from an enhancement of electron-hole separation between PANI and TaON.

Bismuth titanates, Bi2Ti2O7 (BIT), with well-defined spherical structures were synthesized by a facile hydrothermal process without the use of any surfactant or template. XRD and SEM studies have shown that spheres could be fabricated in high yields by simply manipulating the concentrations of hydroxide ions. In this case, hydroxide ions seem to play a pivotal role in controlling the formation of seeds and growth rates of the BIT particles. On the basis of structural analysis of samples obtained at different concentrations of OH-, we also proposed a plausible mechanism to account for the formation of these distinctive morphologies under different conditions. The as-prepared BIT microspheres with good stability exhibited higher photocatalytic activities in the degradation of Rhodamine B (RhB) under visible light irradiation than that in commercial P25 TiO2. Furthermore, the enhanced photocatalytic performance for RhB degradation was also investigated with assistance of a small amount of H2O2. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.

The polycrystalline In2O3 ceramics doped with cobalt were prepared through the spark plasma sintering (SPS) process. Both thermoelectric transport properties and microstructure of the ceramics were investigated. The Co-doped In2O3 by SPS had a remarkable effect on the transport properties. Large electrical conductivity and thermopower was observed in dilute Co-doped sample. The maximum power factor were found in In1.98Co0.02O3 sample as 4.6 x 10-4 W center dot(m center dot K2)-1 at 1073 K with the ZT value up to 0.26.

NiTi shape memory alloys (SMA) with equiatomic composition of Ni and Ti were prepared by electro-deoxidation, in molten calcium chloride, at 950 degrees C. Constant voltage electro-deoxidation was conducted using a NiTiO(3) cathode, and either a carbon anode or a novel CaRuO(3)/CaTiO(3) composite inert anode. Both anode materials successfully allowed NiTi shape memory alloy to be obtained. The primary difference is that molecular oxygen was produced on the inert anode, instead of environmentally undesired CO(2) greenhouse gases on the carbon anode. Indeed, it was found that carbon could successfully be substituted with conductive calcium titanate-calcium ruthenate composites for electro-deoxidation. Furthermore. DSC was used to analyze the phase transformation of NiTi shape memory alloys, with results revealing the existence of reversible martensite-austenite phase transformations during the cooling and heating process. (C) 2010 Elsevier Ltd. All rights reserved.

The anodic dissolution behavior of conductive titanium oxycarbide in NaCl-KCl melt was investigated in detail An emphasis is on the anode gas was analyzed on-line using mass spectra when performing electrolysis. The results showed that TiCxOy. can dissolve in alkali chloride melt During the anodic dissolution, titanium component of TiCxOy dissolves as Ti2+ ion into the molten salt, and the components of carbon and oxygen form carbon monoxide (CO) simultaneously. A series of investigation has been focused on the influences of the current density and the concentration of Ti2+ on the anodic dissolution. An interesting result shows that the faradic dissolution ratio is significantly related to the anodic current density instead of the concentration of Ti2+

An electroanalytial study on the anode process of carbon electrode in LiF-NaF-KF melt was carried out by cyclic voltammetry (CV), chronoamperometry (CA). and gas chromatography. At the potentials higher than 3.7 V versus K+/K the anode effect appeared and generation of perfluorocarbons (PFCs) such as CF4 and C2F6 was observed from the same potential. At 1223 K. the current stayed at very lower level over the range of high potentials (>3.5 V), and only small amount of PFCs was detected, while at lower temperatures, large value of PFCs generation was observed from the potential higher than 7.0 V.

The Ni-Sb binary alloy system was then-nodynamically assessed using CALPHAD approach in this article. Excess Gibbs energies of solution phases, liquid and fcc phases, were formulated using the Redlich-Kister expression. The intermediate phases were modeled by the sublattice model with (Ni,Va)0.5(Ni,Sb)0.25(Ni)0.25 for Ni3Sb_HT phase and (Ni,Va)0.3333(Sb)0.3333(Ni,Va)0.3333 for NiSb phase. The other phases including Ni3Sb, Ni,Sb,, and NiSb2 were treated as stoichiometric compound owing to their narrow composition ranges. Based on the reported thermodynamic properties and phase diagram data, the thermodynamic parameters of these phases were optimized, and the obtained values can reproduce the available experimental data well.

TiO(2) can be reduced by TiC at temperatures in excess of 1000 degrees C, under vacuum conditions. The resulting product was found to show the structures of a Ti(2)CO solid solution, which has excellent conductivity like a metal. A series of experiments have been performed on the possibility of titanium electrolysis, using a Ti(2)CO solid solution as an anode, in a NaCl-KCl melt. Carbon monoxide (CO) was monitored at the anode during electrolysis when the potential was kept constant. The product on the cathode was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that titanium powders can be prepared through electrolysis of a Ti(2)CO solid solution. The oxygen content of the titanium powders was measured and the result shows that it is lower than 300 ppm. (C) 2006 Elsevier B.V. All rights reserved.

In this work, a consumable anode composed of a solid solution of titanium carbide and titanium monoxide was prepared via carbothermic reduction of TiO(2). Upon electrolysis, the anode fed Ti(2+) into solution and carbon monoxide was generated; no excess carbon remained to contaminate the melt. On the cathode, high-purity titanium (>99.9%) was produced. Our results suggest anode and cathode current efficiencies of 93.5% and 89% respectively, indicating that the method is viable and extremely cost-effective, potentially dropping the cost of titanium to near that of aluminum.

溶融炭酸塩燃料電池の電解質として重要なLi₂CO₃-Na₂CO₃およびLi₂CO₃-K₂CO₃二成分系混合溶融塩の粘度を全組成範囲で測定した。低融点で高粘度の混合炭酸塩に対応するためにガス攪拌装置の導入と吊り線の交換によって精度の高い測定を実現した。等温粘度は両二成分系において下に凸の組成依存性を示した。粘度はLi₂CO₃において最も高く、Na₂CO₃あるいはK₂CO₃の増加と共に減少するが、高温では70∼80mol%で最小値を示す。この傾向はLi₂CO₃-K₂CO₃系で顕著である。活性化エネルギーはNa₂CO₃あるいはK₂CO₃の増加と共に単調に減少した。以上の結果と密度の挙動より、これらの二成分系は比較的単純な混合系であるが、混合による体積増加によって粘度の減少を示すものと考えた。溶融炭酸塩燃料電池の作動温度である923K付近の粘度は7∼9mPa·s程度である。

NaNO₃-MNO₃ (M: Li, K, Rb, Cs) 二成分系融体の密度および超音波速度をマノメータ法およびパルス透過法を用いて測定した. 二成分系の全組成について, 融点からそれ以上150Kまでの温度域, アルゴン雰囲気下で測定が行われ, 密度および超音波速度をそれぞれ±0.2%および±0.1%の精度で決定した. いずれの組成においても密度および音速は温度の上昇とともに単調に減少した. 得られた密度および音速より, 融体のモル体積, 断熱および等温圧縮率を求めた. NaNO₃-CsNO₃二成分融体のモル体積は, 加成則よりわずかに正に偏倚するが, 他のNaNO₃-LiNO₃, NaNO₃-KNO₃およびNaNO₃-RbNO₃系のモル体積は, 本研究の測定精度内で加成則に従う. 圧縮率は加成則より1-2%正に偏倚し, アルカリ硝酸塩同士の混合であるNaNO₃-MNO₃系でも完全な理想混合ではないことが判明した.

NaNO₃-MNO₃ (M: Li, K, Rb, Cs) 二成分系融体にパルス透過法を適用し, 超音波の吸収係数を測定した. 二成分系の全組成について, 融点からそれ以上150Kまでの温度域, 15-65MHzの周波数域, アルゴン雰囲気下で測定が行われ, 誤差5%以内で吸収係数を決定した. 吸収係数と周波数の二乗の比, α<i>f</i>^-2の値は全ての組成および温度において, 測定周波数域内で周波数に依存しないことが判った. また吸収係数から求められた体積粘性率は温度に対して負の依存性を示した. しかし, 体積粘性率は組成に強く依存し, KNO₃, RbNO₃およびCsNO₃へのNaNO₃の添加により急激に減少した. 緩和理論を用いて混合塩の体積粘性率の計算式を導き, 単塩でより短い緩和時間を有し寸法のより小さいカチオンからなる成分が混合塩中における緩和時間を支配すると仮定して, 単塩の体積粘性率および断熱圧縮率を用いて計算した結果, 混合塩の体積粘性率は吸収係数から得た値とよく一致した.

The Brillouin scattering experiment has been carried out for molten ZnCl2-KCl binary melts over the composition range 0–45 mol% KCl. The complete profiles of Rayleigh-Brillouin spectra were obtained at scattering angle of 90&deg;, and at temperatures ranging from 550 to 1000 K by the use of carefully purified samples. Marked change in the shape of the spectrum with variations in temperature and composition has been observed and has been concluded to be due to structural relaxation in the melts. A dispersion of sound wave propagation was observed in the melts in the hypersonic region. The spectra have been analyzed based on the viscoelastic theory on the assumption of single relaxation. The sound velocities at the limiting low and high frequencies and the relaxation time have been determined.

In order to clarify the viscoelastic properties of ZnCI2-MCI (M: Na, K) binary melts, hypersonic velocities have been measured in the temperature ranges covering about 150K above the liquidus temperatures of the melts over the composition range of 0 to 50mol% MCI by means of the Brillouin scattering method. Absorption coefficients of ultrasound were measured for molten ZnCI2 at the frequency range of 5-55 MHz. the hypersonic velocity of ZnCI2 decreases linearly with increasing temperature at the high and the low temperature regions, but at the intermediate temperature region, shows a curvilinear temperature dependence, indicating dispersion of sound propagation. © 1993, The Iron and Steel Institute of Japan. All rights reserved.