Interfacial Oxygen Vacancy‐Copper Pair Sites on Inverse CeO<sub>2</sub>/Cu Catalyst Enable Efficient CO<sub>2</sub> Electroreduction to Ethanol in Acid
Yan Qiao, Shenyu Shen, Chenghui Mao, Yongchun Xiao, Wenchuan Lai, Yanan Wang, Xingyu Zhong, Yangfan Lu, Jiong Li, Jingjie Ge, Hsien‐Yi Hsu, Yaqiong Su, Yaqiong Su, Minhua Shao, Zheng Hu, Zheng Hu, Hongwen Huang
Abstract
Abstract Renewable electricity‐driven electrochemical reduction of CO 2 offers a promising route for the production of high‐value ethanol. However, the current state of this technology is hindered by low selectivity and productivity, primarily due to a limited understanding of the atomic‐level active sites involved in ethanol formation. Herein, we identify that the interfacial oxygen vacancy‐neighboring Cu (O v ‐Cu) pair sites are the active sites for CO 2 electroreduction to ethanol. A linear correlation between the density of O v ‐Cu pair sites and ethanol productivity is experimentally evidenced. Moreover, a high Faradaic efficiency of 48.5 % and a partial current density of 344.0 mA cm −2 for ethanol production are achieved over the inverse CeO 2 /Cu catalyst with a high density of O v ‐Cu pair sites in acid. Mechanistic studies that combine density functional theory calculations and spectroscopic techniques propose an O v ‐involved mechanism where interfacial O v sites directly activate and dissociate CO 2 into *CO in a thermodynamically spontaneous manner, thus favoring the subsequent *CHO formation and asymmetric CHO‐CO coupling. Besides, the asymmetric O v ‐Cu pair sites could preferentially stabilize the *CH 2 CHOH intermediate, resulting in the favorable formation of ethanol over ethylene. Our findings provide new atomic‐level insights into CO 2 electroreduction to ethanol, paving the way for the rational design of future catalysts.