Boosting CO<sub>2</sub> Electroreduction to C<sub>2</sub>H<sub>4</sub> <i>via</i> Unconventional Hybridization: High-Order Ce<sup>4+</sup> 4f and O 2p Interaction in Ce-Cu<sub>2</sub>O for Stabilizing Cu<sup>+</sup>
Yanfei Sun, Jiangzhou Xie, Zhenzhen Fu, Huiying Zhang, Yebo Yao, Yixiang Zhou, Xiaoxuan Wang, Shiyu Wang, Xueying Gao, Zheng Tang, Shuyuan Li, Xiaojun Wang, Kaiqi Nie, Zhiyu Yang, Yi‐Ming Yan
Abstract
Efficient conversion of carbon dioxide (CO 2 ) into value-added materials and feedstocks, powered by renewable electricity, presents a promising strategy to reduce greenhouse gas emissions and close the anthropogenic carbon loop. Recently, there has been intense interest in Cu 2 O-based catalysts for the CO 2 reduction reaction (CO 2 RR), owing to their capabilities in enhancing C–C coupling. However, the electrochemical instability of Cu + in Cu 2 O leads to its inevitable reduction to Cu 0, resulting in poor selectivity for C 2+ products. Herein, we propose an unconventional and feasible strategy for stabilizing Cu + through the construction of a Ce 4+ 4f–O 2p–Cu + 3d network structure in Ce-Cu 2 O. Experimental results and theoretical calculations confirm that the unconventional orbital hybridization near E f based on the high-order Ce 4+ 4f and 2p can more effectively inhibit the leaching of lattice oxygen, thereby stabilizing Cu + in Ce-Cu 2 O, compared with traditional d–p hybridization. Compared to pure Cu 2 O, the Ce-Cu 2 O catalyst increased the ratio of C 2 H 4 /CO by 1.69-fold during the CO 2 RR at −1.3 V. Furthermore, in situ and ex situ spectroscopic techniques were utilized to track the oxidation valency of copper under CO 2 RR conditions with time resolution, identifying the well-maintained Cu + species in the Ce-Cu 2 O catalyst. This work not only presents an avenue to CO 2 RR catalyst design involving the high-order 4f and 2p orbital hybridization but also provides deep insights into the metal-oxidation-state-dependent selectivity of catalysts.