采用原位拉曼光谱结合循环伏安法研究银电极在0.1mol/L的Na2SO4溶液中不同电位下的氧化还原过程,在电位扫描过程中,实时记录的拉曼光谱表明,电极表面在0.2V开始生成吸附的原子氧物种;当电位正于0.4V,部分吸附的原子氧扩散进入电极的亚表面区,而另一些则通过强的化学吸附与银表面成键;同时部分银氧化为+1价.各谱带的产生和消失与氧化还原电流峰有很好的对应关系,表明电化学原位拉曼光谱能在分子水平上提供电极在法拉第过程中表面物种成键性质的细节.
Insitu 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.
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