Lead (Pb)-based materials are conventionally used as electrodes in various electrochemical systems. However, the chemical state of the surface films working as electrocatalysts has not been clarified in oxygen evolution reaction (OER) environment. In this study, we investigated the chemical state and microstructure of surface films generated on a Pb electrode during OER in a sulfuric acid solution by operando microscopic electrochemical (EC) Raman spectroscopy. The EC-Raman spectra revealed that the Pb-related compounds and crystal structure of the surface films depend on the applied potential and analysis point. Notably, at the main analysis point, a sharp band of β-PbO₂ was detected as the main phase in the OER potential region and its intensity increased with increase in the applied potential. On the other hand, at another analysis point, the band for β-PbO₂ did not appear in the same potential region. Instead, α-PbO₂ and β-PbO, which have a lower electronic conductivity than β-PbO₂, were detected, and the band intensities were almost unchanged by increasing the potential up to 1.9 V. The results indicate that the local environment significantly affects the chemical states of EC-generated surface films on a Pb electrode and β-PbO₂ acts as the main OER active site.

中文翻译：

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析氧反应下铅电极上产生的电催化剂层的原位鉴定


铅 （Pb） 基材料通常用作各种电化学系统中的电极。然而，在析氧反应 （OER） 环境中，用作电催化剂的表面膜的化学状态尚未阐明。在这项研究中，我们通过原位显微电化学 （EC） 拉曼光谱研究了 OER 在硫酸溶液中 OER 过程中在 Pb 电极上产生的表面膜的化学状态和微观结构。EC-Raman 光谱显示，Pb相关化合物和表面膜的晶体结构取决于施加的电位和分析点。值得注意的是，在主分析点，检测到 β-PbO₂ 的尖峰带作为 OER 电位区域的主相，其强度随着施加电位的增加而增加。另一方面，在另一个分析点，β-PbO₂ 的谱带没有出现在同一个潜在区域。相反，检测到电子电导率低于 β-PbO₂ 的 α-PbO₂ 和 β-PbO，并且通过将电位增加到 1.9 V，谱带强度几乎没有变化。结果表明，局部环境显著影响 Pb 电极上 EC 生成的表面膜的化学状态，β-PbO₂ 是主要的 OER 活性位点。