摘要
以钨丝为工作电极,通过循环伏安法研究碳酸乙烯酯-氯化铝(EC-AlCl3)溶剂化离子液体中Ta(Ⅴ)的电化学还原机理。在EC-AlCl3-TaCl5离子液体的循环伏安曲线中出现4个还原峰,其中-0.55、-0.72和-1.12 V(vsAl)处还原峰对应的反应为Ta(Ⅴ)络合离子三步还原为金属钽,包括Ta(Ⅳ)和Ta(Ⅲ)络合离子的形成。络合离子Ta(Ⅲ)被还原为金属钽的过程受扩散控制且不可逆,其在323K下的扩散系数为3.7×10^-7cm^2/s,扩散活化能为77k J/mol。另外,对323K下的阴极产物进行扫描电子显微镜、能量分散光谱和X射线光电子能谱分析。结果表明,在-0.8 V下恒电位电沉积2 h的产物为金属钽和钽的氧化物。
To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.Four reduction peaks were observed in the cyclic voltammogram of the EC-AlCl3-TaCl5 ionic liquid.The reduction peaks at-0.55,-0.72,and-1.12 V(vs Al)were related to the reduction of Ta(Ⅴ)to tantalum metal by three stages including the formation of Ta(Ⅳ)and Ta(Ⅲ)complex ions.The reduction of Ta(Ⅲ)to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10^-7 cm^2/s at 323 K,and the diffusion activation energy was 77 k J/mol.Moreover,the cathode products at 323 K were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray photoelectron spectroscopy.The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at-0.8 V for 2 h.
作者
刘爱民
郭梦霞
吕梓阳
张保国
刘风国
陶文举
杨酉坚
胡宪伟
王兆文
刘玉宝
石忠宁
Ai-min LIU;Meng-xia GUO;Zi-yang LÜ;Bao-guo ZHANG;Feng-guo LIU;Wen-ju TAO;You-jian YANG;Xian-wei HU;Zhao-wen WANG;Yu-bao LIU;Zhong-ning SHI(Key Laboratory for Ecological Metallurgy of Multimetallic Mineral,Ministry of Education,Northeastern University,Shenyang 110819,China;State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)
基金
Projects(N182503033
N172502003)supported by the Fundamental Research Funds for the Central Universities,China
Project(2018M640258)supported by Postdoctoral Research Foundation of China
Project(GUIKE AA18118030)supported by Guangxi Innovation-driven Development Program,China。
关键词
电化学行为
离子液体
循环伏安法
氯化铝
钽
electrochemical behavior
ionic liquid
cyclic voltammetry
aluminum chloride
tantalum