High‐rate CO<sub>2</sub>‐to‐CH<sub>4</sub> Electrosynthesis by Undercoordinated Cu Sites in Alkaline‐Earth‐Metal Perovskites with Strong Basicity
Zikai Xu, Peng Chen, Gan Luo, Songtao Yang, Pinger Yu, Shuai Yan, Mohsen Shakouri, Zhiqiang Wang, Tsun‐Kong Sham, Gengfeng Zheng
Abstract
Abstract The electrochemical CO 2 reduction to CH 4 has been extensively demonstrated, but still suffers from relatively poor activity and requires high overpotentials especially at large electrolysis rates. Perovskite oxides (A x B y O) are one type of promising electrocatalyst for the CO 2 reduction due to their tunable electronic structures. In this work, a Ca 2 CuO 3 perovskite oxide catalyst is developed with alkaline‐earth A‐sites, featuring an inherently strong basic strengthand outstanding capability for CO 2 adsorption, as well as the undercoordinated Cu sites generated through partial surface Ca 2+ cation leaching. The Ca 2 CuO 3 catalyst exhibitsa high partial current density of 517 ± 23 mA cm −2 for producing CH 4 at a low applied potential of −0.30 V versus reversible hydrogen electrode, which further reached to a peak value of 1452 ± 156 mA cm −2 . Density functional calculations show that the undercoordinated Cu sites allowed to promote the hydrogenation of * CO and subsequent * CHO intermediates, thus leading to the high CH 4 activity. This work suggests an attractive design strategy for tuning the A‐sites in perovskite oxides to realize high‐rate CO 2 ‐to‐CH 4 electrosynthesis with low overpotentials.