Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species, and their spatial distribution. Here we used tip-enhanced Raman spectroscopy (TERS) to study the catalytic hydrogenation of chloronitrobenzenethiol on a well-defined Pd(submonolayer)/Au(111) bimetallic catalyst (\(p_{\rm{H}_{2}}\) = 1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (~10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at Au sites as far as 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfers. We demonstrate TERS to be a powerful analytical tool that provides a unique approach to spatially investigate the local structure–reactivity relationship in catalysis.

要了解当地环境中催化加氢的机理，需要涉及催化位置，活性氢种类及其空间分布的化学和地形信息。在这里，我们使用尖端增强拉曼光谱（TERS）研究了在定义明确的Pd（亚单层）/ Au（111）双金属催化剂（\（p _ {\ rm {H} _ {2}} \ ） = 1.5 bar，298 K），同时以纳米级分辨率（〜10 nm）绘制了表面形貌和化学指纹信息。催化氢化后表面的TERS成像确认反应发生在Pd位点之外。结果表明，氢溢出加速了Au位距双金属Pd / Au边界20 nm处的氢化。密度泛函理论用于阐明界面氢转移的热力学。我们证明了TERS是一种功能强大的分析工具，它提供了一种独特的方法来在空间上研究催化中的局部结构与反应性关系。