Catalytic dehydrogenation of ethylbenzene with carbon dioxide: promotional effect of antimony in supported vanadium–antimony oxide catalyst

Alumina-supported vanadium oxide, VO_x/Al₂O₃, and binary vanadium–antimony oxides, VSbO_x/Al₂O₃, have been tested in the ethylbenzene dehydrogenation with carbon dioxide and characterized by S_BET, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction and CO₂ pulse methods. VSbO_x/Al₂O₃ exhibited enhanced catalytic activity and especially on-stream stability compared to VO_x/Al₂O₃ catalyst. Incorporation of antimony into VO_x/Al₂O₃ increased dispersion of active VO_x species, enhanced redox properties of the systems and formed a new mixed vanadium–antimony oxide phase in the most catalytically efficient V_0.43Sb_0.57O_x/Al₂O₃ system.     

Using of textured polycrystalline SbSI in actuators

This paper presents the design and fabrication of a light deflector made from textured polycrystalline antimony sulfoiodide (SbSI) obtained by gradient freezing during the rapid quenching from the liquid state. The piezoelectric and electrostriction parameters of the textured polycrystalline SbSI are evaluated from the reflection measurements. First time the electrostrictive constant of this material (4.6(1) × 10⁻¹³ m²/V²) is reported.     

Effect of Sb implantation on copper silicides formation and morphology after annealing of Cu/Si structures

In this work, the solid state reaction between a thin film of copper and silicon has been studied using Rutherford backscattering spectroscopy, X-ray diffraction, scanning electron microscopy and microprobe analysis. Cu films of 400 and 900 Å thicknesses are thermally evaporated on Si(1 1 1) substrates, part of them had previously been implanted with antimony ions of 5×10¹⁴ or 5×10¹⁵ at. cm⁻² doses. The samples are heat-treated in vacuum at temperatures in the range 200–700 °C for various times. The results show the growth and formation of Cu₃Si and Cu₄Si silicides under crystallites shape dispatched on the sample surface, independently of the implantation dose. On the other hand, it is established that the copper layer is less and less consumed as the antimony dose increases, resulting in the accumulation of Sb⁺ ions at silicide/Si interface and in the silicide layer close to surface. The exposure of samples to air at room temperature shows the stability of Cu₄Si phase whereas the Cu₃Si silicide disappears to the benefit of the silicon dioxide formation. The observed phenomena are discussed.     

极谱催化波测定金属锑中痕量硒

本文较详细的研究了SeSO_3~=-IO_4~--K_2CO_3体系的条件。此体系的空白值比SeSO_3~=-IO_4~--NH_4Cl体系低100倍,检测下限为5×10~(-5)微克/毫升;E_p=-0.85V(VS.S.C.E.)。利用金属锑能被硝酸浸蚀而变成Sb_2O_4的特性,在溶样过程中使硒与基体锑分离。锑的分离效果为98.7%以上,硒的回收率为95—104%。     

Antimony Mobilization through Two Contrasting Gold Ore Processing Systems,New Zealand

Antimony, a toxic metalloid similar to arsenic, is present at variable levels in most gold-bearing rocks. Antimony is soluble in the surface environment, so antimony (Sb) mobilization in mine waters is an environmental issue around gold mines. The Reefton gold mine was originally developed in gold-bearing quartz veins; Sb concentrations were low (<100 mg/kg) compared to arsenic (As) concentrations (>1,000 mg/kg), and the mine waters had low dissolved Sb (<0.1 mg/L). A second stage of gold mineralization at Reefton involved brecciation and cataclasis of quartz veins and wall rocks, with addition of stibnite (Sb₂S₃). Processing of this ore has resulted in higher dissolved Sb in mine waters (0.1–1 mg/L), even after water treatment that removes most dissolved As (to 0.01 mg/L) by adsorption to suspended iron oxyhydroxide. Competition between As and Sb for adsorption sites on iron oxyhydroxide particles may have resulted in partial exclusion of the more weakly adsorbed Sb. The high rainfall (2,000 mm/year) at Reefton ensures adequate dilution of mine waters after discharge. The Macraes gold mine has no stibnite, and most Sb is in solid solution in the abundant arsenopyrite (Sb up to 2,000 mg/kg). Pit waters have both Sb and As dissolved up to 0.1 mg/L, partly because of evaporative concentration in a low-rainfall environment. Macraes tailings waters have high As (up to 3 mg/L) but negligible Sb (<0.001 mg/L). Reefton mine gold-bearing concentrate, containing stibnite, is transported 700 km to be processed by autoclave oxidation and cyanidation at the Macraes mine. This introduction of additional Sb to the Macraes site substantially increases the Sb content of the process stream periodically. Tailings from this process have up to 3 wt% Sb, dispersed through As-rich iron oxyhydroxides that are formed in the autoclave. The Sb-rich tailings are strongly diluted (approximately 100:1) by the Macraes tailings, and adsorption of Sb to iron oxyhydroxides in the tailings piles ensures that there has been no increase in the Sb content of the tailings water since the Reefton concentrate has been added at Macraes.     

Hydrothermal method for the synthesis of Sb2Te3, and Bi0.5Sb1.5Te3 nanoplates and their thermoelectric properties

In this study, a modified hydrothermal method is reported for the preparation of Sb₂Te₃ and Bi_0.5Sb_1.5Te₃ nanoplates and their bulk samples was prepared by spark plasma sintering (SPS). The crystal structure, morphology, and thermoelectric properties were investigated. The microstructure results indicate that the bulk samples consisted nanograins after SPS. The presence of nanograins, high Seebeck coefficient (181 μV/K), high electrical conductivity (763 Ω^?1 cm^?1), and low thermal conductivity (1.15 W/mK) has been achieved in Sb₂Te₃ nanoplate bulk samples. As a result, the dimensionless thermoelectric figure of merit (ZT) of 0.55 at 400 K was achieved. Moreover, the peak ZT shifted to higher temperature compared with other reported results found in literature.     

Hydrothermal-assisted derived ion-imprinted sorbent for preconcentration of antimony(III) in water samples

Ion-imprinted iodole-functionalized silica-supported (IIS) sorbent was prepared by the hydrothermal-assisted surface imprinting approach. IIS indicated had a high static adsorption capacity of 39.6 mg·g^–1 for Sb(III), displayed stable removal efficiency in the range of pH 4–9, offered a rapid removal rate with an equilibrium within 30 min, and could be used repeatedly without a considerable adsorption capacity loss. The IIS sorbent had been successfully applied to solid-phase extraction coupled with hydride generation atomic fluorescence spectrophotometry for the preconcentration and determination of Sb(III) in certified reference materials and real water samples, since recoveries in the range of 97.6%–102.8% were obtained.     

Selective oxidation of propane over alkali-doped Mo–V–Sb–O catalysts

Alkali metal-doped MoVSbO catalysts have been prepared by impregnation of a MoVSbO-mixed oxide (prepared previously by a hydrothermal synthesis) and finally activated at 500 or 600 °C in N₂. The catalysts have been characterized and tested for the selective oxidation of propane and propylene. Alkali-doped catalysts improved in general the catalytic performance of MoVSbO, resulting more selective to acrylic acid and less selective to acetic acid than the corresponding alkali-free MoVSbO catalysts. However, the specific behaviour strongly depends on both the alkali metal added and/or the final activation temperature. At isoconversion conditions, catalysts activated at 600 °C present selectivity to acrylic acid higher than that achieved on those activated at 500 °C, both K-doped catalysts presenting the highest yield to acrylic acid. The changes in the number of acid sites as well as the nature of crystalline phases can explain the catalytic behaviour of alkali-doped MoVSbO catalysts.     

Nonaqueous and template-free synthesis of Sb doped SnO2 microspheres and their application to lithium-ion battery anode

Antimony doped SnO₂ (ATO) microspheres composed of ATO nanoparticles were prepared by using a hydrothermal process in a nonaqueous and template-free solution from the inorganic precursors (SnCl₄ and Sb(OC₂H₅)₃). The physical properties of the as-synthesized samples were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption isotherms, and X-ray photoelectron spectrum (XPS). The resulting particles were highly crystalline ATO microspheres in the diameter range of 3-10 μm and with many pores. The as-prepared samples were used as negative materials for lithium-ion battery, whose charge-discharge properties, cyclic voltammetry, and cycle performance were examined. The results showed that a high initial discharge capacity of 1981 mAh g⁻¹ and a charge capacity of 957 mAh g⁻¹ in a potential range of 0.005-3.0 V was achieved, which suggests that tin oxide-based materials work as high capacity anodes for lithium-ion rechargeable batteries. The cycle performance is improved because the conducting ATO nanoparticles can also perform as a better matrix for lithium-ion battery anode.     

Anodic stripping voltammetric measurement of trace heavy metals at antimony film carbon paste electrode

The antimony film carbon paste electrode (SbF-CPE) was prepared in situ on the carbon paste substrate electrode as a “mercury-free” electrochemical sensor. Its aptitude for measuring some selected trace heavy metals has been demonstrated in combination with square-wave anodic stripping voltammetry in non-deaerated model solutions of 0.01 M hydrochloric acid with pH 2. Some important operational parameters, such as deposition potential, deposition time, and concentration of antimony ions were optimized, and the electroanalytical performance of the SbF-CPE was critically compared with both bismuth film carbon paste electrode (BiF-CPE) and mercury film carbon paste electrode (MF-CPE) using Cd(II) and Pb(II) as test metal ions. In comparison with BiF-CPE and MF-CPE, the SbF-CPE exhibited superior electroanalytical performance in more acidic medium (pH 2) associated with favorably low hydrogen evolution, improved stripping response for Cd(II), and moreover, stripping signals corresponding to Cd(II) and Pb(II) at the SbF-CPE were slightly narrower than those observed at bismuth and mercury counterparts. In addition, the comparison with antimony film electrode prepared at the glassy carbon substrate electrode displayed higher stripping current response recorded at the SbF-CPE. The newly developed sensor revealed highly linear behavior in the examined concentration range from 5 to 50 μg L⁻¹, with limits of detection (3σ) of 0.8 μg L⁻¹ for Cd(II), and 0.2 μg L⁻¹ for Pb(II) in connection with 120 s deposition step, offering good reproducibility of ±3.8% for Cd(II), and ±1.2% for Pb(II) (30 μg L⁻¹, n = 10). Preliminary experiments disclosed that SbF-CPE and MF-CPE exhibit comparable performance for measuring trace concentration levels of Zn(II) in acidic medium with pH 2, whereas its detection with BiF-CPE was practically impossible. Finally, the practical applicability of SbF-CPE was demonstrated via measuring Cd(II) and Pb(II) in a real water sample.