Preparation, Characterization, and Electrocatalytic Properties of Tin Silicomolybdate and Tin Oxide/Silicomolybdate Film Modified Electrodes

Abstract

Two types film of tin silicomolybdate and tin oxide/silicomolybdate films have been prepared directly from the mixing of and ions from the strong acidic solutions over different scanning potential ranges. The cyclic voltammogram of the growing type I film (assigned as a tin silicomolybdate film) is characterized by two redox couples and the type II film (assigned as a tin oxide/silicomolybdate film) exhibits three redox couples and both films were confined to the immobilized film when transferred to a aqueous solution. In addition to cyclic voltammetry, an electrochemical quartz crystal microbalance and UV-visible absorption spectroscopy were used to study the growth mechanism of the tin silicomolybdate and tin oxide/silicomolybdate films. The results show that and ions react slowly to form a new blue-colored species with absorption peaks at , 645, and . The electrocatalytic reduction of , , , , , and ions by a tin oxide/silicomolybdate film or a tin silicomolybdate film were investigated in acidic aqueous solutions. The electrocatalytic reactions of ions with a tin oxide/silicomolybdate film were investigated using the rotating ring-disk electrode method.