Reaction product-driven restructuring and assisted stabilization of a highly dispersed Rh-on-ceria catalyst
Reaction product-driven restructuring and assisted stabilization of a highly dispersed Rh-on-ceria catalyst
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DOI：
10.1038/s41929-022-00741-2
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发表时间：
2022-02
期刊：
影响因子：
37.8
通讯作者：
Ge Yan;Yu Tang;Yuting Li;Yixiao Li;L. Nguyen;T. Sakata;K. Higashi;F. Tao;P. Sautet
中科院分区：
文献类型：
--
作者：
Ge Yan;Yu Tang;Yuting Li;Yixiao Li;L. Nguyen;T. Sakata;K. Higashi;F. Tao;P. Sautet
了解催化剂在反应条件下的结构动力学是具有挑战性的，但对于催化剂设计是至关重要的。在这里，我们通过原位/操纵态表征和第一性原理模拟相结合的方法，证明了负载型Rh催化剂在甲烷水蒸气重整过程中生成的气态产物一氧化碳(CO)在原子尺度上发生了结构调整。尽管在氢气预处理过程中，初始制备的单一Rh阳离子催化剂转化为Rh纳米粒子，但在催化条件下形成的Rh纳米粒子重新分散到低核度的共配基Rh簇合物(RHM(CO)n(m= 1-3，n= 2-4))。在反应条件下的理论模拟表明，CO产物的压力稳定了RHM(CO)n位，而原位/OPANDO谱显示在CO压力的驱动下Rh3(CO)3团簇和无CO配体的Rh团簇之间发生了可逆的重组。我们的发现证明了将产物分子包括在原子尺度上对催化活性中心和机理的理解的重要性。
Understanding the structural dynamics of a catalyst under reaction conditions is challenging but crucial regarding catalyst design. Here, by a combination of in situ/operando characterization and first-principles modelling, we show that supported rhodium (Rh) catalysts undergo restructuring at the atomic scale in response to carbon monoxide (CO), a gaseous product formed during steam reforming of methane. Despite transformation of the initially prepared single-Rh-cation catalyst into Rh nanoparticles during hydrogen pretreatment, the formed Rh nanoparticles redispersed to low-nuclearity, CO-liganded Rh clusters (Rhm(CO)n(m= 1–3,n= 2–4)) under catalytic conditions. Theoretical simulations under reaction conditions suggest that the pressure of the CO product stabilizes Rhm(CO)nsites, while in situ/operando spectroscopy revealed a reversible restructuring between Rh3(CO)3clusters and CO-ligand-free Rh clusters driven by CO pressure. Our findings demonstrate the importance of including product molecules in the atomic-scale understanding of catalytic active sites and mechanisms.