催化作用
化学
乙二醇
选择性
氢溢流
铜
吸附
氢
无机化学
乙烯
光化学
物理化学
有机化学
作者
Qing‐Nan Wang,Ruizhi Duan,Zhendong Feng,Ying Zhang,Peng Luan,Zhaochi Feng,Jijie Wang,Can Li
标识
DOI:10.1021/acscatal.3c04740
摘要
Understanding the synergy of Cu0 and Cu+ in hydrogenation reactions is indispensable for reasonably modulating the product distributions and improving the catalyst design. Herein, we investigated the hydrogenation of dimethyl oxalate on CeZrOx-supported Cu with varying molar ratios of nCu+/nCu0. A volcano-type correlation of structure and activity indicates that the selectivity of ethylene glycol is strongly dependent on the nCu+/nCu0 ratio, arising from the matching of rates for the activation of carbonyl group-included reactants and H2 on Cu+ and Cu0, respectively. The maximal selectivity toward ethylene glycol is achieved at a ratio of 0.15; deviating from this value leads to the favorable formation of methyl glycolate, a primary product. Results obtained from temperature-programmed surface reactions indicate that the presence of Cu+ and oxygen vacancies (OV) reduces the reaction temperature for the hydrogenation of carbonyl groups. Theoretical data show that the OV located at the copper–ceria interface induces a downward-directed adsorption configuration of the reaction intermediate adsorbed at the Cu+ site, compared to the presence of an upward-directed counterpart at the Cu0–Cu+ center. This change leads to a reduction in the kinetic barrier for the subsequent hydrogenation step, which consumes active *H species transferred from adjacent Cu0 via a hydrogen spillover process. Manipulating the Cu valence state and oxygen vacancies via interfacial engineering offers a viable strategy for governing product distributions, serving as an inspiration for the design of selective hydrogenation catalysts.
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