Electrochemical behavior of tantalum in ethylene carbonate and aluminum chloride solvate ionic liquid  

钽在碳酸乙烯酯-氯化铝溶剂化离子液体中的电化学行为

作　　者：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 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(东北大学多金属共生矿生态化冶金教育部重点实验室,沈阳110819;包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室,包头014030;东北大学轧制技术及连轧自动化国家重点实验室,沈阳110819)

机构地区：[1]Key Laboratory for Ecological Metallurgy of Multimetallic Mineral,Ministry of Education,Northeastern University,Shenyang 110819,China [2]State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China [3]State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第8期2283-2292,共10页中国有色金属学报（英文版）

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。

摘　　要：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.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。

关 键 词：electrochemical behavior ionic liquid cyclic voltammetry aluminum chloride TANTALUM 

分 类 号：TF841.6[冶金工程—有色金属冶金]