Wang Si-Dun, Ma Tong-Mei, Li Xiao-Na, He Sheng-Gui
China School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou 510641, P. R. China.
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
J Phys Chem A. 2024 Feb 1;128(4):738-746. doi: 10.1021/acs.jpca.3c06445. Epub 2024 Jan 18.
CO oxidation represents an important model reaction in the gas phase to provide a clear structure-reactivity relationship in related heterogeneous catalysis. Herein, in combination with mass spectrometry experiments and quantum-chemical calculations, we identified that the RhMnO cluster cannot oxidize CO into gas-phase CO at room temperature, while the NO preadsorbed products RhMnO[(NO)] are highly reactive in CO oxidation. This discovery is helpful to get a fundamental understanding on the reaction behavior in real-world three-way catalytic conditions where different kinds of reactants coexist. Theoretical calculations were performed to rationalize the crucial roles of preadsorbed NO where the strongly attached NO on the Rh atom can greatly stabilize the products RhMnO[(NO)] during CO oxidation and at the same time works together with the Rh atom to store electrons that stay originally in the attached CO unit. The leading result is that the desorption of CO, which is the rate-determining step of CO oxidation by RhMnO, can be greatly facilitated on the reactions of RhMnO[(NO)] with CO.
CO氧化反应是气相中的一个重要模型反应，用于在相关多相催化中提供清晰的结构-反应活性关系。在此，结合质谱实验和量子化学计算，我们发现RhMnO团簇在室温下不能将CO氧化为气相CO，而预吸附NO的产物RhMnO[(NO)]在CO氧化反应中具有高反应活性。这一发现有助于深入理解在不同反应物共存的实际三元催化条件下的反应行为。进行了理论计算，以阐明预吸附NO的关键作用，即Rh原子上强烈吸附的NO在CO氧化过程中能极大地稳定产物RhMnO[(NO)]，同时与Rh原子协同作用，存储原本存在于吸附的CO单元中的电子。主要结果是，在RhMnO[(NO)]与CO的反应中，CO的脱附（RhMnO氧化CO的速率决定步骤）能得到极大促进。
