Insight into the Balancing Effect of Active Cu Species for Hydrogenation of Carbon鈥揙xygen Bonds

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• 作者：Yue Wang ; Yongli Shen ; Yujun Zhao ; Jing Lv ; Shengping Wang ; Xinbin Ma
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：October 2, 2015
• 年：2015
• 卷：5
• 期：10
• 页码：6200-6208
• 全文大小：599K
• ISSN：2155-5435

文摘

Hydrogenation of carbon鈥搊xygen (C鈥揙) bonds plays a significant role in organic synthesis. Cu-based catalysts have been extensively investigated because of their high selectivity in C鈥揙 hydrogenation. However, no consensus has been reached on the precise roles of Cu⁰ and Cu⁺ species for C鈥揙 hydrogenation reactions. Here we resolve this long-term dispute with a series of highly comparable Cu/SiO₂ catalysts. All catalysts represent the full-range distribution of the Cu species and have similar general morphologies, which are detected and mutually corroborated by multiple characterizations. The results demonstrate that, when the accessible metallic Cu surface area is below a certain value, the catalytic activity of hydrogenation linearly increases with increasing Cu⁰ surface area, whereas it is primarily affected by the Cu⁺ surface area. Furthermore, the balancing effect of these two active Cu sites on enhancing the catalytic performance is demonstrated: the Cu⁺ sites adsorb the methoxy and acyl species, while the Cu⁰ facilitates the H₂ decomposition. This insight into the precise roles of active species can lead to new possibilities in the rational design of catalysts for hydrogenation of C鈥揙 bonds.