Promoted Electrochemical CO <sub>2</sub> Methanation over Ultrastable Cu(II)-V <sub>O</sub> Pair Sites in Cu-CeO <sub>2</sub> Catalyst: Water Activation and Intermediate Adsorption Tuning
Min Wang, Yangen Xie, Minghui Fang, Yichi Zhang, Yajuan Wang, Zijun Zhang, Shuaiqiang Jia, Chunjun Chen, Haihong Wu, Mingyuan He, Buxing Han
Abstract
Electrochemical CO 2 methanation powered by renewable electricity provides a sustainable strategy for producing value-added products, solving global energy problems, and realizing carbon recycling. However, it is hindered by unexpected intermediate desorption and slow water dissociation kinetics, greatly restricting the activity and selectivity of electrochemical CO 2 methanation. Here, we designed a Cu-CeO 2 catalyst with Cu(II)-oxygen vacancy (V O ) pair sites, which shows high activity and selectivity in electrochemical CO 2 reduction to methane (CH 4 ). The catalytic system achieves a remarkable CH 4 Faradaic efficiency (FE) of 70% with a current density as high as 485 mA cm –2 at −1.1 V vs RHE in the flow cell. A combination of in situ characterizations and theoretical calculation unveiled that the isolated Cu(II) site strongly adsorbs the *CO intermediate, while V O effectively accelerates water dissociation to provide abundant *H. The synergistic effect of isolated Cu(II) sites and V O promotes *CO hydrogenation, resulting in high activity and selectivity of CH 4 . This work provides valuable insights for the rational design of efficient multisite synergistic catalytic systems.