Specific construction of asymmetric carbon-nickel-chlorine single-atom sites via carbon vacancy engineering for efficient CO<sub>2</sub> electroreduction.

Hao, Qi; Tang, Qi; Zheng, Lirong; Liu, Kai; Wu, Junxiu; Lu, Jun · Nat Commun · 2025

basic_science · Level V

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Abstract

Breaking the structural symmetry of active sites in single-atom catalysts (SACs) allows efficient regulation of the electron distribution around the metal centers, holding great promise for promoting their performance in electrocatalytic carbon dioxide reduction reaction (ECO<sub>2</sub>RR). Herein, we propose a vacancy-engineering strategy for constructing asymmetric carbon-nickel-chlorine (C-Ni-Cl) sites in Ni SAC (Ni<sub>1</sub>-C/Cl). In strongly acidic media (pH=1), Ni<sub>1</sub>-C/Cl achieves Faradaic efficiency over 98% for carbon monoxide (CO) product at the operated current density of 500 mA cm<sup>-2</sup>. In situ X-ray absorption spectra reveal that during electrocatalysis, the C<sub>3</sub>-Ni-Cl sites exhibit potential-dependent structure evolutions, which can optimize their adsorption configurations for the reactive species. Theoretical calculations demonstrate that the Ni-C/Ni-Cl co-coordination induces the asymmetric electron distribution in C<sub>3</sub>-Ni-Cl sites, resulting in the regulation of the electronic properties of the Ni centers, thereby optimizing the reaction pathway of CO<sub>2</sub>-to-CO on these single-atom sites. This work extends the synthesis of SACs containing asymmetric single-atom sites, provides insights into designing industrial-oriented electrocatalysts toward other important electrocatalytic reactions.