The catalytic behavior of Rh particles supported by three different materials (Rh, Au, and ZrO₂) in H₂ oxidation has been studied in situ by correlative photoemission electron microscopy (PEEM) and scanning photoemission electron microscopy (SPEM). Kinetic transitions between the inactive and active steady states were monitored, and self-sustaining oscillations on supported Rh particles were observed. Catalytic performance differed depending on the support and Rh particle size. Oscillations varied from particle size-independent (Rh/Rh) via size-dependent (Rh/ZrO₂) to fully inhibited (Rh/Au). For Rh/Au, the formation of a surface alloy induced such effects, whereas for Rh/ZrO₂, the formation of substoichiometric Zr oxides on the Rh surface, enhanced oxygen bonding, Rh-oxidation, and hydrogen spillover onto the ZrO₂ support were held responsible. The experimental observations were complemented by micro-kinetic simulations, based on variations of hydrogen adsorption and oxygen binding. The results demonstrate how correlative in situ surface microscopy enables linking of the local structure, composition, and catalytic performance.

中文翻译：

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通过催化反应的原位相关显微镜成像界面和粒度效应

通过相关光电子显微镜 (PEEM) 和扫描光电子显微镜 (SPEM) 原位研究了三种不同材料（Rh、Au 和 ZrO ₂ ）负载的 Rh 粒子在 H _{2氧化中的催化行为。}监测了非活性和活性稳态之间的动力学转变，并观察到支撑 Rh 粒子的自持振荡。催化性能因载体和 Rh 粒径而异。振荡从与粒径无关 (Rh/Rh) 到与粒径相关 (Rh/ZrO ₂ ) 到完全抑制 (Rh/Au) 不等。对于 Rh/Au，表面合金的形成引起了这种效应，而对于 Rh/ZrO ₂，在 Rh 表面形成亚化学计量的 Zr 氧化物，增强氧键合，Rh 氧化，以及氢溢出到 ZrO ₂载体上。基于氢吸附和氧结合的变化，实验观察得到微观动力学模拟的补充。结果证明了相关的原位表面显微镜如何能够将局部结构、组成和催化性能联系起来。