Low‐Coordinated Ni Single Atom Catalyst with Carbon Coordination for Efficient CO ₂ Electroreduction

Abstract

Abstract In essence, electrocatalytic CO 2 reduction reaction (CO 2 RR) process for the CO 2 ‐to‐CO conversion involves two critical reactive intermediates: *COOH and *CO. The trade‐off between the adsorption of *COOH and the desorption of *CO is challenging for Ni‐based CO 2 RR catalysts. The high‐valence Ni site is inadequate in supplying sufficient electrons for CO 2 activation and subsequent adsorption of *COOH; conversely, the metallic Ni site with abundant electron exhibits excessively strong π‐backbonding with *CO, thus hindering its desorption. Here, the study reports a low‐coordinated Ni single atom catalyst (SAC) characterized by a low‐coordinated structure with carbon coordination, thereby engineering a moderate electron depletion at its Ni sites. This Ni SAC achieves a high selectivity for CO production up to 99.1% in H‐cell. Additionally, it maintains an ultrahigh CO selectivity near 100% across a broad range of current densities in flow cell, coupled with sustained stability at a large current of 250 mA cm −2 for 20 h. Both in situ characterization results and density functional theory (DFT) calculations confirm the dual functionality of this low‐coordinated structure, as it enhances the adsorption of *COOH while concurrently facilitating the subsequent desorption of *CO, thus greatly promoting the overall CO 2 RR process.