Thermoanalytical study and structure of stoichiometric As–Sb–S glasses

The glass-forming system (As₂S₃)_100?x(Sb₂S₃)_x was studied by thermal analysis (conventional and StepScan differential scanning calorimetry) and Raman spectroscopy. It was found that the bulk glasses are homogeneous up to x = 60, while supercooled melts are unstable and when x ≥ 40, Sb₂S₃ (stibnite) crystallizes during heating. Depending on the chemical composition, the glass transition temperature initially increases as the Sb₂S₃ concentration is increased from 0 to 5 %, decreases to a minimum at ~20 %, and then gradually increases as the concentration is further increased and the main Raman peak also shifts non-monotonically. Combining these results with chemometric analysis of the Raman spectra showed that the image of the structure of the studied glasses can be described by the linear combination of three chemically different stable clusters, rather than by the chains crossing model, CCM, and that the properties of the glasses are controlled by medium-range order.     

Structural Arrangement of Fe–Sb–O Catalysts

In iron–antimony catalysts containing excess antimony oxide and consisting of a mixture of FeSbO₄ and -Sb₂O₄ phases, the structure of iron antimonate changes compared to the catalyst with an equimolar composition, which is the pure FeSbO₄ phase. In the presence of excess antimony oxide in the near-surface layer of iron antimonate, extended defects with a structure of crystallographic shift are formed. These accumulate overstoichiometric antimony. Such a structural change is associated with changes in the acid–base properties and the surface oxygen binding strength.     

Comparative thermodynamic study of Ga–In–Sb system

The results of comparative thermodynamic analysis of Ga–In–Sb system are presented in this paper. Investigations, carried out in the section from Ga corner with molar ratio of In:Sb equal to 1:1, were done experimentally, using Oelsen calorimetry at the temperature 873 K and analytically, applying different calculation methods—Toop and Muggianu, in the temperature interval from 873 to 1673 K. Excess molar Gibbs energies and activity of all components in specified temperature interval were calculated.     

Glass transition and crystallization kinetics analysis of Sb–Se–Ge chalcogenide glasses

Differential thermal analysis (DTA) has been employed to investigate the effect of Ge addition on the glass transition behavior and crystallization kinetics of Sb₁₀Se_90?xGe_x (x = 0, 19, 21, 23, 25, 27) alloys. The three characteristic temperatures viz. glass transition (T _g), crystallization (T _c), and melting (T _m) have been determined and found to vary with the heating rates and Ge content. Thermal stability and glass forming tendency have been evaluated in terms of ΔT (= T _c ? T _g) and reduced glass transition temperature. The activation energies for glass transition and crystallization have been used to analyze the nucleation and growth process. The activation energy analysis also determines the suitability of alloys to be used in switching applications. Results have been interpreted in terms of bond energies and structural transformations in the investigated alloys.     

Thermodynamic and surface properties of Ge–Ga and Ge–Sb liquid alloys

Thermodynamic and surface properties of Ge–Ga and Ge–Sb liquid alloys have been studied using statistical mechanical formulations based on complex formation and that based on the concept of layered structure near the interface. The study showed that low level of complex formation of the form Ge _{2 Sb} exists in Ge–Sb toward the Ge-rich end of the concentration range and the surface properties of Ge–Ga are almost equal to their corresponding bulk equivalent.     

Thermal stability and crystallization kinetics of ternary Se–Te–Sb semiconducting glassy alloys

This paper presents the results of kinematical studies of glass transition and crystallization in glassy Se_85?x Te₁₅Sb _x (x = 2, 4, 6 and 8) using differential scanning calorimetry (DSC). From the dependence on heating rates of, the glass transition temperatures (T _g), and temperature of crystallization (T _p) the activation energy for glass transition (E _g) and the activation energy for crystallization (E _c) are calculated and their composition dependence can be discussed in term of the average coordination number and cohesive energy. The thermal stability of Se_85?x Te₁₅Sb _x was evaluated in terms of criterion ΔT = T _c ? T _g and kinetic criteria K(T _g) and K(T _p). By analyzing the crystallization results, the crystallization mechanism is characterized. Two (two- and three-dimensional growth) mechanisms are working simultaneously during the amorphous–crystalline transformation of the Se₈₃Te₁₅Sb₃ alloy while only one (three-dimensional growth) mechanism is responsible for the crystallization process of the chalcogenides Se_85?x Te₁₅Sb _x (x = 4, 6 and 8) glass. The phases at which the alloy crystallizes after the thermal process have been identified by X-ray diffraction.     

Electrochemical reduction synthesis of In–Sb nanoropes and terraced micropyramids

Here we report that the nanoropes and terraced micropyramids of In–Sb semiconductors can be successfully synthesized at room temperature. The electrochemical route shows a simple, quick and economical method for the preparation of various In–Sb semiconductor nanostructures. The possible formation mechanisms of In–Sb nanoropes and terraced micropyramids are proposed in this paper. The UV–vis absorption spectra of the prepared In–Sb nanoropes and terraced micropyramids were recorded to reveal the correlation between the optical properties and the morphologies of the samples.     

FTIR study of the sol–gel synthesis of cementitious gels: C–S–H and N–A–S–H

The study explored the compatibility between the main product of Portland cement hydration and the main product of the alkali activation of fly ash: C–S–H and N–A–S–H gels, respectively. Both gels were synthesized with laboratory reagents at different pH values. Blends of the two were synthesized as well, using the sol–gel procedure. All the gels were characterized with Fourier transform IR spectroscopy (FTIR). The gels synthesized with this procedure were shown to precipitate together with a silica-rich gel. In addition, the pH level was found to play a determinant role in both C–S–H and N–A–S–H gel synthesis. The C–S–H gel is the major phase formed at pH > 11 and N–A–S–H gel for pH > 12. The results relating to the joint synthesis of the two (C–S–H and N–A–S–H) gels were not conclusive. Technique used for the characterization failed to differentiate between them in the blended material.

Effect of electron radiation on electrical parameters of Zn/n-Si/Au–Sb and Zn/ZnO/n-Si/Au–Sb diodes

In this study, RF-magnetron sputtered ZnO thin film as an interlayer was used to improve radiation tolerance of the Schottky diodes. The structural and optical measurements showed that the ZnO thin films have hexagonal crystal structure with preferential c-axis orientation, 20.39 nm grain sizes and 3.15 eV bandgap. The electrical parameters such as ideality factor, barrier height and series resistance of Zn/n-Si/Au–Sb and Zn/ZnO/n-Si/Au–Sb diodes were calculated before and after electron radiation at 25, 50 and 75 gray doses. Deviation values of the parameters showed that the ZnO as an interlayer caused to improved radiation tolerance of the diodes.

     

Influence of fluoride-doped tin oxide interlayer on Ni–Sb–SnO2/Ti electrodes

In the present work, fluoride-doped tin oxide (FTO) as an interlayer was introduced into nickel and antimony co-doped tin dioxide coated titanium electrodes to investigate the influence of FTO interlayer on the structural properties and lifetime performance of the electrodes. Scanning electron microscopy and X-ray diffraction techniques were used to characterize the morphology and crystal structure of the electrodes with or without FTO interlayer. The electrode surface became smoother with FTO interlayer introduced while the crystallite size reduced. Electrochemical impedance spectroscopy was also adopted to analyze the electrodes’ electrochemical behavior. With FTO interlayer introduced, the formation of titanium dioxide-insulating layer on the titanium substrate was significantly retarded during the anodic process. The accelerated lifetime tests presented that the lifetime of the electrodes with proper FTO interlayer was six times longer than that without FTO interlayer. The mechanisms for the electrodes’ lifetime enhancement with FTO interlayer were discussed.     

Enthalpies of mixing of liquid systems for lead-free soldering: Cu–Sb–Sn system

Using two different types of high temperature drop calorimeters, partial and integral enthalpies of mixing of liquid alloys were determined in the ternary Cu–Sb–Sn system. The system was investigated along four sections at 1100 K. Experimental data were used to find ternary interaction parameters by applying the Redlich–Kister–Muggianu model for substitutional solutions, and a full set of parameters describing the concentration dependence of the enthalpy of mixing was derived. From these, the isoenthalpy curves were constructed for 1100 K. The entire system shows exothermic enthalpy of mixing at the given temperature.     

The Structure of Oxide Ga–Sb–Ni–P–W–O/SiO2 Catalyst and Its Catalytic Properties in Propane Ammoxidation

The structure of the multicomponent catalyst Ga₁Ni₁P₂W_0.5Sb₆O _x /SiO₂ and its catalytic properties in propane ammoxidation are studied. The catalyst is nanostructured and consists of noncoherently spliced blocks of a multiply promoted phase with a structure of gallium antimonate, which covers SiO₂ particles with a thin layer. In the multiply promoted compound with a structure of gallium antimonate, Ni²⁺ ions partially substitute for Ga³⁺ and W⁶⁺ ions partially substitute for Sb⁵⁺. This leads to an increase in the crystalline lattice parameters a and c. Phosphate ions are stabilized in the region of block interfaces. The catalyst is characterized by high efficiency in propane ammoxidation.     

Ternary invariant point at 403 and 455?°C in the Al–Sb–Zn system

The temperature and location of the invariant eutectic point at 403?°C in the zinc-rich corner of the Al?CSb?CZn system was determined. However, the experimentally determined temperature was found to be lower than the thermodynamically predicted one. Differential thermal analyses, differential scanning calorimetry, and quantitative microstructural analyses were used to determine this specific reaction. The determined ternary eutectic reaction, L??????-Sb₂Zn₃?+?AlSb?+???-Zn, represents the last solidification path in the phase region of Sb?CAlSb?CZn. Before a ternary eutectic reaction takes place, another reaction is also possible near the Sb?CZn binary system, a quasi-peritectic reaction at 455?°C: L?+???-Sb₂Zn₃????AlSb?+???-Sb₂Zn₃. A scanning electron microscope equipped with an energy-dispersive spectrometer was used for the microstructural analyses. The phase identification was conducted with X-ray diffractometry. The experimental data were compared to the thermodynamic predictions made with the CALPHAD method using the SSOL4 database.     

Electrodeposition and lithium storage performance of novel three-dimensional porous Fe–Sb–P amorphous alloy electrode

The three-dimensional porous Fe–Sb–P amorphous alloy electrodes were prepared by electroplating on porous copper current collector. The structure and electrochemical performance of the electroplated Fe–Sb–P amorphous alloy electrodes have been investigated in detail. XRD results showed that the as-deposited Fe–Sb–P alloy electrode exhibits an amorphous nature. Electrochemical tests indicated that at the 50th cycle, the Fe–Sb–P amorphous alloy electrodes can deliver a discharge capacity of 448 mAh g^?1. The porous and amorphous structure of electrode of Fe–Sb–P alloy was beneficial in relaxing the volume expansion during cycling, which improved the cycle ability of Fe–Sb–P alloy electrode.     

可见光响应新型催化剂Sb2S3降解甲基橙研究

自1972年科学家发现在TiO_2半导体电极上可以发生光解水反应以来,光催化材料的研究逐渐成为新型光电功能材料研究领域中的一个热点。目前研究较多、活性较高的TiO_2和ZnO等宽禁带半导体材料,仅能被紫外光所激发;同时为了提高光催化剂的高活性,制备出的纳米级催化剂(粉体或薄膜)的光吸收带边往往会因量子尺寸效应而进一步蓝移。实际上到达地表的太阳辐射能量主要集中于460-500nm波长范围内,紫外成分(300—400nm)不足5%,因此要想高效地利用太阳光进行光催化反应,光催化剂必须为可见光响应型。本文通过液相反应制备了红棕色的无定形Sb_2S_3以及固相反应制备了黑色的晶态Sb_2S_3,并利用XRD粉末衍射和UV-Vis吸收光谱表征样品的物相和吸收光谱特性。在样品的光催化活性测试中,采取甲基橙作为染料光降解的模型,研究了各种条件下的降解效率,证实了光催化反应的存在,并初步探讨了其光催化性能的影响机制。实验表明,在使用420nm滤波片的相同的实验条件下,与P25、CdS等已经报导的催化剂对比,发现Sb_2S_3具有更优异的光催化性能,其光催化效率大约是CdS的3.5倍。同时,本文中制备的无定形Sb_2S_3和晶态Sb_2S_3的吸收边分别为660nm和800nm,带隙约为1.88ev和1.55ev,小于目前已见报导的多数可见光催化剂。通过使用截止型滤波片,我们发现对于600nm以上波长的可见光,两种形态的Sb_2S_3仍具有光催化活性。     

Sb2S3纳米丝的合成及杂化太阳电池研究

利用溶剂热方法制备出高质量的Sb₂S₃纳米丝, 并将其与聚(2-甲氧基-5-(2-乙基己氧基)-1,4-对苯乙炔)(MEH-PPV)共混制备成体型结构聚合物太阳电池.利用X射线衍射、扫描电子显微镜、透射电子显微镜和紫外-可见吸收光谱对Sb₂S₃纳米丝进行表征, 利用电流-电压(J-V)测试和电池的光电转换效率(IPCE)谱研究了Sb₂S₃纳米丝含量对Sb₂S₃/MEH-PPV共混体型结构太阳电池性能的影响.结果表明, 合成的Sb₂S₃纳米丝直径为60~70 nm, 长度为4~6 μm, 沿[001] 晶向生长, 在紫外-可见光区有较强的吸收, 光学带隙为1.57 eV.电池性能测试结果表明, Sb₂S₃纳米丝作为辅助光吸收材料及有效的电子传输材料, 提高了对可见光的利用率; Sb₂S₃的补充吸收作用使Sb₂S₃/MEH-PPV共混电池具有一定的宽谱响应特点; 与不含Sb₂S₃的电池相比, Sb₂S₃/MEH-PPV共混电池中增加的MEH-PPV/Sb₂S₃界面提高了光生激子分离效率, 从而提高了电池的效率.     

可见光响应新型催化剂Sb2S3降解甲基橙研究

自1972年科学家发现在TiO2半导体电极上可以发生光解水反应以来，光催化材料的研究逐渐成为新型光电功能材料研究领域中的一个热点。目前研究较多、活性较高的砷TiO2和ZnO等宽禁带半导体材料，仅能被紫外光所激发；同时为了提高光催化剂的高活性，制备出的纳米级催化剂（粉体或薄膜）的光吸收带边往往会因量子尺寸效应而进一步蓝移。实际上到达地表的太阳辐射能量主要集中于460-500nm波长范围内，紫外成分（300-400nm）不足5％，因此要想高效地利用太阳光进行光催化反应，光催化剂必须为可见光响应型。本文通过液相反应制备了红棕色的无定形Sb2S3以及固相反应制备了黑色的晶态Sb2S3，并利用XRD粉末衍射和UV-Vis吸收光谱表征样品的物相和吸收光谱特性。在样品的光催化活性测试中，采取甲基橙作为染料光降解的模型，研究了各种条件下的降解效率，证实了光催化反应的存在，并初步探讨了其光催化性能的影响机制。实验表明，在使用420nm滤波片的相同的实验条件下，与P25、CdS等已经报导的催化剂对比，发现Sb2S3具有更优异的光催化性能，其光催化效率大约是CdS的3．5倍。同时，本文中制备的无定形Sb2S3和晶态Sb2S3的吸收边分别为660nm和800nm，带隙约为1．88ev和1．55ev，小于目前已见报导的多数可见光催化剂。通过使用截止型滤波片，我们发现对于600nm以上波长的可见光，两种形态的Sb2S3仍具有光催化活性。     

Thermodynamic studies of the surface and transport properties in Ag–In and Ag–Sb liquid alloys

The surface tension, surface concentration, viscosity and mutual diffusion co-efficients of the Ag–In and Ag–Sb liquid alloys have been calculated using energetics and derivables from a statistical mechanical framework which recognises the formation of atom clusters of self associates. Our calculations suggest the existence of some form of local order in the systems. Ag–In showed higher tendencies to heterocoordination in the bulk-manifested higher values of mutual diffusion coefficient throughout the concentration range. The viscosity values of Ag–In and Ag–Sb were calculated using the expression reported by Kucharsky which relates the viscosity of a liquid binary alloy to the activity coefficients of the liquid alloy components that are raised to some power m. This exponent m is a fitted parameter. The calculated viscosity values for Ag–Sb had some reasonable agreement with experiment above 0.5 atomic fraction of Sb, using a fitted parameter value of m = 4.5. The fitted parameter value for the viscosity of Ag–In is expected to be in the range 1.5 ≤ m ≤ 3.5.     

Thermodynamic analysis of AuIn–Sb system using Oelsen calorimetry and predicting methods

The results of comparative thermodynamic analysis of AuIn–Sb section in ternary Au–In–Sb system are presented in this paper. Investigation was carried out experimentally, using Oelsen calorimetry at the temperature 873 K and analytically, applying different predicting methods––Toop and Muggianu in the temperature interval from 873 K to 1673 K. The values for integral molar Gibbs excess energies and antimony activities have been determined and compared at temperature of 873 K, which indicated to good agreement between experimental results and results obtained using Toop predicting model.