关键词: 原位拉曼光谱, 银电极, 氧化还原过程

Abstract: Insitu Raman spectroscopy combined with cyclic voltammogram measurements was used to investigate formation of oxygen species at Ag electrode surfaces during the oxidation and reduction process in 0.1 mol/L Na_2SO_4 solution. The time dependent Raman spectra show that at potentials positive of 0.2 V, adsorption of oxygen atom occurs, while at the potentials positive of 0.4 V, some oxygen atoms migrate into subsurface of the Ag electrode and the other form strongly bound oxygen on the surface through chemical bond. At the same potentials, part of the silver atoms are oxidized and form Ag_2SO_4. During the negative potential ex cursion, the band centered at 960 and 1 054 cm-1 respectively at about 0.3 V, indicates that the reduction current peak at 0.34 V is resulted from the reduction of the Ag_2SO_4. Another reduction current peak at 0.24 V, which corresponds to the decomposing of the surface oxygen species.