关键词: 银电极, 溴化银形成, 循环伏安法, 电化学

Abstract: The nucleation process of the AgBr film formed on porous silver which is plated on Pt electrode can be divided into three steps. The first involved the 2-dimensional nucleation of AgBr deposoted at Br^- adsorbed locations (perhape certain crystal face, defects, kink’s and jogs). The second and third are 3-dimensional nucleation of AgBr, which are characterized by two anodic praks respectively. The kinetics of formation of AgBr film on silver is limited by physical parameters such as ionic diffusion and migration. When the bromide concentration was low, the diffusion of Br^- in solution is the limiting step. When the bromide concentration is relatively high, then a layer of AgBr containing holes was formed, and the current is controlled by the diffusion of bromide ions into the lenthening holes of the film. In the meantime, the dissolution and deposition of AgBr occurred, and the holes in the film were filled up. The rate of film growth was then limited by the solid-state electromigration of silver ions through the AgBr film.The morphology of the continuous kinetic oxidation process of the porous silver plated on Pt electrode had been substantiated by comprehensive scanning electron microscope investigations.

Key words: silver electrode silver bromide cyclic voltammetry electrochemistry