Asymmetrically Coordinated Ni-Based Single-Atom Catalyst Enables Ultra-Wide Potential Window for Ampere-Level CO2 Electroreduction

Conventional Ni–N 4 single-atom catalysts (SACs) hold great promise in sustainable energy conversion and storage, but suffer from weak * COOH adsorption and narrow potential windows during CO 2 electroreduction (CO 2 RR). To address this limitation, herein we report an asymmetric Ni–N 3 O 1 SAC prepared via an oxygen-mediated spatial confinement pyrolysis strategy. Theoretical calculations predict that this unique asymmetric coordination can effectively lower the * COOH formation energy, promote the interaction between the catalyst and * COOH, and suppress the competing hydrogen evolution reaction in CO 2 RR. The prepared Ni–N 3 O 1 SAC features a distorted planar quadrilateral structure and demonstrates exceptional performance in CO 2 -to-CO conversion, with a maximum turnover frequency of 207 700 h −1 , a maximum CO partial current density of 810 mA cm −2 , and CO Faradaic efficiency of ≥ 99% over an ultra-wide potential window of 2100 mV (−0.3 to −2.4 V vs. reversible hydrogen electrode) in a flow cell. A combination of in situ spectroscopic measurements verifies the reversible structural evolution and robust stability of the Ni–N 3 O 1 SAC under CO 2 RR conditions, as well as the strengthened * COOH formation and accelerated CO 2 activation kinetics. This work provides a feasible route for designing and synthesizing high-performance asymmetrically coordinated SACs toward industrial CO 2 -to-CO conversion.