Fabrication of Cu–CeO<sub>2</sub> Catalyst with Abundant Interfacial Cu<sup>+</sup>–O–Ce<sup>3+</sup>–O<sub>V</sub> (Oxygen Vacancy) Sites for Boosting CO<sub>2</sub> Electroreduction to Methane
Shao-Chen Wang, Xiang Ji, Rui Hou, Longlong Qi, Peng Jing, Xuan Xu, Baocang Liu, Jun Zhang
Abstract
Accelerating the conversion of *CO to *CHO and promoting the adsorption and hydrogenation of *CHO are the keys to achieving a highly selective electrocatalytic CO 2 reduction reaction (CO 2 RR) to CH 4 over Cu-based catalysts. Herein, a novel electrocatalyst comprising highly dispersed Cu nanoclusters (Cu NCs ) supported on oxygen vacancy (O V )-rich CeO 2 on carbon paper (Cu NCs –CeO 2 /CP) with plentiful interfacial Cu + –O–Ce 3+ –O V sites is constructed via a facile electrodeposition method. Various in situ / ex situ characterizations and theoretical calculations unveil that the Cu + –O–Ce 3+ –O V sites can effectively regulate the pathway of the CO 2 RR, accelerate the *CO → *CHO process, stabilize the *CHO and *OCH 3 intermediates, and promote their hydrogenation to produce CH 4 . Furthermore, the critical role of Ce 3+ and the O V species in forming Cu + –O–Ce 3+ –O V to maintain the electrocatalytic CO 2 RR activity is revealed. The optimized Cu NCs –CeO 2 /CP electrocatalyst exhibits a CH 4 Faradaic efficiency of 68.3% at 500 mA cm –2, with a high partial current density of 340 mA cm –2 .