Dynamic Restructuring of Coordinatively Unsaturated Copper Paddle Wheel Clusters to Boost Electrochemical CO<sub>2</sub> Reduction to Hydrocarbons**
Wei Zhang, Chuqiang Huang, Jiexin Zhu, Qiancheng Zhou, Ruohan Yu, Yali Wang, Pengfei An, Jing Zhang, Ming Qiu, Liang Zhou, Liqiang Mai, Zhiguo Yi, Ying Yu
Abstract
Abstract The electrochemical reduction of CO 2 to hydrocarbons involves a multistep proton‐coupled electron transfer (PCET) reaction. Second coordination sphere engineering is reported to be effective in the PCET process; however, little is known about the actual catalytic active sites under realistic operating conditions. We have designed a defect‐containing metal–organic framework, HKUST‐1, through a facile “atomized trimesic acid” strategy, in which Cu atoms are modified by unsaturated carboxylate ligands, producing coordinatively unsaturated Cu paddle wheel (CU−CPW) clusters. We investigate the dynamic behavior of the CU−CPW during electrochemical reconstruction through the comprehensive analysis of in situ characterization results. It is demonstrated that Cu 2 (HCOO) 3 is maintained after electrochemical reconstruction and that is behaves as an active site. Mechanistic studies reveal that CU−CPW accelerates the proton‐coupled multi‐electron transfer (PCMET) reaction, resulting in a deep CO 2 reduction reaction.