n 型 Bi-Te-Se 温差电材料溶液体系的电沉积过程研究

目的研究硫酸体系中元素铋、碲和硒的电沉积行为,为电沉积制备n型Bi2Te3-ySey温差电材料提供理论参考。方法采用电化学循环伏安测试技术,对硫酸溶液体系中铋、碲、硒三种元素的电沉积及不同元素间的共沉积过程进行研究。结果纯铋硫酸溶液体系中,Bi3+还原成单质铋的电化学反应是分步进行的,游离态和络合态的铋离子先后发生还原反应。纯碲硫酸溶液体系中,HTe O2+以吸附态和游离态两种形式先后发生还原反应。纯硒硫酸溶液体系中,溶液中的H2Se O3也通过分步还原反应生成硒单质。在Bi-Te-Se三元硫酸溶液体系中,Bi3+的浓度和基材对电沉积过程有显著影响,Bi-Te-Se化合物对电沉积过程具有促进作用。结论在Bi-Te-Se三元硫酸溶液体系中,Se,Te和Bi元素可依次在阴极表面发生还原反应而实现共沉积,从而制备出n型Bi-Te-Se温差电材料。

Investigations on the Electrodepositing Behaviors of the n-type Bi-Te-Se Thermoelectric Material Solution System

Objective To study the electrochemical behavior of Bi, Te and Se in sulfuric acid system, providing the theoretical reference for the electrodeposition process of n-type Bi2Te3-y Sey thermoelectric material. Methods The electrochemical reduction processes of elements Bi, Te and Se in sulfuric acid solution system as well as the codeposition among different elements were investigated by cyclic voltammogram measurements. Results In Bi solution system, the electrochemical reduction process of Bi3+ to elemental Bi could be divided in steps, and the free Bi Bismuth ions and complexed bismuth ions were reduced in sequence. In Te solution system, the adsorbed HTeO2 + and the fress HTeO2 + were reduced in sequence. In Se solution system, the H2SeO3 in the solution was also reduced to elemental Se through several steps. In the solution system containing elements Bi, Te and Se, the concentration of Bismuth ions and the difference between substrates had significant influences on the electrodeposition process. The BiTe-Se compound as cathode could stimulate the following electrodeposition. Conclusion In Bi-Te-Se ternary sulfuric acid electrolytes, a co-electrodepositing process of elements Se, Te, Bi could take place on the surface of the cathode through reduction to form Bi-Te-Se compound as n-type thermoelectric material.