熔盐电解可控制备纳米半导体(Si, Ge)粉体的基础研究

项目名称： 熔盐电解可控制备纳米半导体(Si, Ge)粉体的基础研究

项目编号： No.21203141

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理化学

项目作者： 肖巍

作者单位： 武汉大学

项目金额： 25万元

中文摘要： 在氯化物熔盐中电化学还原固态氧化物是节能环保的半导体粉体的制备新方法。但是，目前对于这一新方法反应机理的认识还比较有限，其中氧化物前驱物的电化学还原被认为主要是一个固相（如二氧化硅）到固相（如硅）的过程。而本课题组初期的理论和实验研究表明，固态二氧化硅在氯化钙熔盐中的电化学还原过程中存在着溶解-沉积这一涉及液态的过程，即在电化学界面原位离子化的氧和二氧化硅化合生成硅酸钙，而硅酸钙可以溶解在熔盐中并被电化学还原为硅。本项目围绕"熔盐电解固态氧化物时原位微区中的液态过程"这一关键的科学问题，探索实现电解产物的纳米结构和电解能量效率调控的途径，以期加深对熔盐电解固态化合物这一普适的材料制备新方法以及绝缘固态化合物电极的电化学反应机理的基本认识，并为开发基于熔盐电沉积法的半导体粉体的可连续化生产工艺提供理论指导。

中文关键词： 熔盐电解；电化学；硅；锗；固态氧化物

英文摘要： Electrochemical reduction of solid oxides in molten chlorides was recently proposed to be an energy-saving and environmental friendly extraction process for semiconductor powders. However, the present insights on the electro-reduction mechanism of the above novel method remain far from exhaustedly specified, in which the cathodic reduction mechanism is widely accepted to be a solid-to-solid reaction. Our preliminary study provides the verifications on the existence of unheeded dissolution-electrodeposition mechanism during electrochemical reduction of solid silica in molten calcium chloride, in which soluble silicates are generated via the reaction between the acidic silica and in-situ ionized oxygen on the cathode, and the dissolved silicates are subsequently electrodeposited into silicon on the cathode. With focus on fully understanding the in-situ liquid process at the electrochemical interface during electro-reduction of solid oxides in molten salts, the solutions towards controllable nanostructured electrolytic products and optimized energy efficiency would be systematically investigated, which shall enlarge the understanding not only on the versatile elecrolytic extraction method involving electro-reduction solid oxides in molten salts, but also on the electrochemical mechanisms of insulating solid compoun

英文关键词： molten salt electrolysis；electrochemistry；silicon；germanium；solid oxide