Instituto de Electroquímica, Universidad de Alicante, Alicante, Spain.
Phys Chem Chem Phys. 2011 Oct 6;13(37):16762-71. doi: 10.1039/c1cp21909j. Epub 2011 Aug 24.
The oxidation of adsorbed CO on Pt single crystal electrodes has been studied in alkaline media. The surfaces used in this study were the Pt(111) electrode and vicinal stepped and kinked surfaces with (111) terraces. The kinked surfaces have either (110) steps broken by (100) kinks or (100) steps broken by (110) kinks and different kink densities. The voltammetric profiles for the CO stripping on those electrodes show peaks corresponding to the oxidation of CO on the (111) terraces, on the (100) steps/kinks and on the (110) steps/kinks at very distinctive potentials. Additionally, the stripping voltammograms always present a prewave. The analysis of the results with the different stepped and kinked surfaces indicates that the presence of the prewave is not associated with defects or kinks in the electrode surface. Also, the clear separation of the CO stripping process in different peak contributions indicates that the mobility of CO on the surface is very low. Using partial CO stripping experiments and studies at different pH, it has been proposed that the low mobility is a consequence of the negative absolute potential at which the adlayers are formed in alkaline media. Also, the surface diffusion coefficient for CO in these media has been estimated from the dependence of the stripping charge of the peaks with the scan rate of the voltammetry.
在碱性介质中研究了 Pt 单晶电极上吸附的 CO 的氧化。本研究中使用的表面是 Pt(111)电极和具有（111）平台的倾斜阶跃和扭折表面。这些扭折表面具有（110）台阶被（100）扭折打断，或者（100）台阶被（110）扭折打断，扭折密度不同。这些电极上 CO 脱附的伏安曲线显示出与（111）平台上 CO 的氧化、（100）台阶/扭折上的 CO 的氧化以及（110）台阶/扭折上的 CO 的氧化相对应的峰，在非常独特的电位下。此外，脱附伏安曲线总是呈现前波。对不同阶跃和扭折表面的结果进行分析表明，前波的存在与电极表面的缺陷或扭折无关。此外，CO 脱附过程在不同峰贡献中的清晰分离表明，CO 在表面上的迁移率非常低。通过部分 CO 脱附实验和在不同 pH 值下的研究，提出低迁移率是由于在碱性介质中形成吸附层的绝对负电位造成的。此外，还从伏安法的扫描速率对峰的脱附电荷的依赖性出发，估计了 CO 在这些介质中的表面扩散系数。
