A Study on the Oxidation of Hydrogen peroxide at Au(111) and Au(100) Electrodes
- 2016年第22卷 
本文利用旋转圆盘电极系统研究了酸性介质中H2O2在Au(100)和Au(111)电极表面的电化学行为. 实验发现在Au电极上H2O2难以发生还原，但是当电位稍微正于H2O2氧化为O2的平衡电势时即可发生氧化. 在Au(111)上H2O2氧化的起始电位比在Au(100)正0.1 V左右. Au(100)上的双桥位位点能增强反应中间体*OOH的吸附，可能是导致Au(100)上H2O2氧化反应超电势比Au(111)低的主要原因. 在较正电位区(E>1.2 V), 当电极表面被氧物种覆盖时，H2O2在两个电极上的氧化都会受到一定程度的抑制，这种影响在Au(111)上比Au(100)上更加明显，这与Au(111)上氧物种的生成与逆向还原可逆性差的趋势一致. 最后还将Au与Pt单晶电极上H2O2氧化的行为进行了对比分析.The oxidation reactions of hydrogen peroxide (H2O2) at Au(111) and Au(100) electrodes in 0.1 mol·L-1 HClO4 were investigated by using rotating disk electrode system. It was found that H2O2 could be readily oxidized to O2 at both Au(100) and Au(111) surfaces with the onset potential close to its equilibrium potential. In contrast, the onset overpotential for H2O2 reduction was above 0.4 V, while the onset overpotential for H2O2 oxidation at Au(100) was ca. 0.1 V more negative than that at Au(111), this is probably due to special double bridge sites which facilitate the adsorption of OOH* intermediates and its further splitting of the O-H bond. When the electrode potential exceeded 1.2 V, the Au surface was gradually covered by oxides, which significantly inhibit the oxidation reaction of H2O2. The inhibition effect became more obvious at Au(111) than that at Au(100), which corresponds well to the worse reversibility for the formation and reduction of Au oxides at Au(111). Finally, the comparisons in the H2O2 oxidation behaviors at Au(100) and Au(111) with that at Pt(111) indicated that the onset potential for H2O2 oxidation at Pt(111) should also be quite close to its equilibrium potential, and the observed high onset anodic current was due to the mixed potential effects of both the oxidation and reduction of H2O2 which occurred at the interface simultaneously.