Stabilizing copper sites in coordination polymers toward efficient electrochemical C-C coupling
Yongxiang Liang, Jiankang Zhao, Yang Yu, Sung‐Fu Hung, Jun Li, Shuzhen Zhang, Yong Zhao, An Zhang, Cheng Wang, Dominique Appadoo, Lei Zhang, Zhigang Geng, Fengwang Li, Jie Zeng
Abstract
Abstract Electroreduction of carbon dioxide with renewable electricity holds promise for achieving net-zero carbon emissions. Single-site catalysts have been reported to catalyze carbon-carbon (C-C) coupling—the indispensable step for more valuable multi-carbon (C 2+ ) products—but were proven to be transformed in situ to metallic agglomerations under working conditions. Here, we report a stable single-site copper coordination polymer (Cu(OH)BTA) with periodic neighboring coppers and it exhibits 1.5 times increase of C 2 H 4 selectivity compared to its metallic counterpart at 500 mA cm − 2 . In-situ/operando X-ray absorption, Raman, and infrared spectroscopies reveal that the catalyst remains structurally stable and does not undergo a dynamic transformation during reaction. Electrochemical and kinetic isotope effect analyses together with computational calculations show that neighboring Cu in the polymer provides suitably-distanced dual sites that enable the energetically favorable formation of an *OCCHO intermediate post a rate-determining step of CO hydrogenation. Accommodation of this intermediate imposes little changes of conformational energy to the catalyst structure during the C-C coupling. We stably operate full-device CO 2 electrolysis at an industry-relevant current of one ampere for 67 h in a membrane electrode assembly. The coordination polymers provide a perspective on designing molecularly stable, single-site catalysts for electrochemical CO 2 conversion.