Steering the Reaction Pathway of CO<sub>2</sub> Electroreduction by Tuning the Coordination Number of Copper Catalysts
Jiapeng Jiao, Xinchen Kang, Jiahao Yang, Shuaiqiang Jia, Yaguang Peng, Shiqiang Liu, Chunjun Chen, Xueqing Xing, Mingyuan He, Haihong Wu, Buxing Han
Abstract
Cu-based catalysts are optimal for the electroreduction of CO 2 to generate hydrocarbon products. However, controlling product distribution remains a challenging topic. The theoretical investigations have revealed that the coordination number (CN) of Cu considerably influences the adsorption energy of *CO intermediates, thereby affecting the reaction pathway. Cu catalysts with different CNs were fabricated by reducing CuO precursors via cyclic voltammetry (Cyc-Cu), potentiostatic electrolysis (Pot-Cu), and pulsed electrolysis (Pul-Cu), respectively. High-CN Cu catalysts predominantly generate C 2+ products, while low-CN Cu favors CH 4 production. For instance, over the high-CN Pot-Cu, C 2+ is the main product, with the Faradaic efficiency (FE) reaching 82.5% and a partial current density ( j ) of 514.3 mA cm –2 . Conversely, the low-CN Pul(3)-Cu favors the production of CH 4, achieving the highest FE CH4 value of 56.7% with a j CH4 value of 234.4 mA cm –2 . In situ X-ray absorption spectroscopy and Raman spectroscopy studies further confirm the different *CO adsorptions over Cu catalysts with different CN, thereby directing the reaction pathway of the CO 2 RR.