Sb(Ⅲ)在碱性木糖醇溶液中的阴极电沉积(英文)

Electrodeposition of Sb(Ⅲ) in alkaline solutions containing xylitol

运用循环伏安法、线性电位扫描法研究木糖醇在碱性溶液(含锑)中的电化学稳定性及锑在木糖醇碱性溶液中的沉积动力学参数;采用计时电流法研究锑在不锈钢阴极上的电化学成核机理。循环伏安测试结果表明,木糖醇在碱性溶液中的稳定性较好,在-1.20V～+0.60V(vsHg/HgO)范围内无氧化还原反应发生,在电位负于-1.70V(vs.Hg/HgO)时木糖醇在锑电极上可能发生分解。在该体系中,锑在阴极上的沉积经历了不可逆电结晶过程。根据线性电势扫描结果,锑沉积的活化能、表观传递系数、交换电流密度等动力学参数分别为46.33kJ/mol、0.64和4.40×10-6A/m2。计时电流法实验结果表明,锑在碱性木糖醇溶液中的成核机理符合扩散控制下的三维连续成核模型,外加电位对晶体生长速率和恒定电位下的饱和晶核密度有显著影响。通过分析恒电位阶跃曲线,求出锑离子在该体系中的扩散系数为1.53×10-6cm2/s。

The electrodeposition of antimony in alkaline solutions containing xylitol was investigated using cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The antimony electrodeposition and the chemical stability of xylitol in alkaline solutions were studied by cyclic voltammetric technique.Apparent activation energy,apparent transfer coefficient and exchange current density were obtained by linear sweep voltammetric technique.Initial stages of antimony electrocrystallization were determined by chronoamperometry.Xylitol in alkaline solutions exhibits high chemical stability and there is no redox in solutions when the potential ranges from-1.20 V to ＋0.60 V（vs Hg/HgO）.There is no other redox reaction but hydrolysis occurring on stainless steel in the potential range of-1.75 V to 1.25 V（vs Hg/HgO） while the xylitol decomposition maybe take place on antimony electrode when potential is more negative than-1.70 V（vs Hg/HgO）.Cyclic voltammograms with different scan rates indicate that the antimony electrodeposition process is an electrocrystallization which is a completely irreversible electrode process.The apparent activation energy,apparent transfer coefficient and exchange current density were calculated to be 46.33 kJ/mol,0.64 and 4.40×10-6 A/m2,respectively.The analyses of the chronoamperometric responses support the view of a three-dimensional growth under progressive nucleation.The average diffusion coefficient of antimony was calculated to be 1.53×10-6 cm2/s.