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本文采用循环伏安法研究了镀银铂电极在溴化钾溶液中的成核过程及氧化动力学,结果表明:AgBr的形成包括三个步骤,首先在银表面某些吸附Br~-的特殊位置上以平面方式成核,然后经过二个三维的成核步骤。在较低浓度的KBr溶液中,AgBr的形成由溶液中的Br~-迁移控制。在较高浓度的溶液中,由于生成的AgBr膜是高度松散的,速度控制步骤转化为在膜孔内Br~-的迁移。随着AgBr的生成以及AgBr的溶解沉积作用,膜孔被堵塞,同时反应速度转化为由AgBr膜中的Ag~+迁移控制。电镜结果也支持了以上结论。
Cyclic voltammetry was used to study the nucleation process and oxidation kinetics of platinum-plated platinum electrode in potassium bromide solution. The results showed that the formation of AgBr consisted of three steps. Firstly, some special Br- Nucleate in a planar manner and then go through two three-dimensional nucleation steps. In lower concentrations of KBr solution, AgBr formation is controlled by Br ~ - migration in solution. In higher concentration solutions, the velocity control step translates to Br ~ - migration in the membrane pores due to the highly loose AgBr film formed. With the formation of AgBr and the dissolution and deposition of AgBr, the pore of the membrane was blocked and the reaction rate was changed to be controlled by Ag ~ + migration in the AgBr film. Electron microscopy results also support the above conclusion.