Self-Supported Nickel Single Atoms Overwhelming the Concomitant Nickel Nanoparticles Enable Efficient and Selective CO2 Electroreduction

Self-supported metal/nitrogen-doped carbon (M-N-C) catalysts with unitary single-atom (SA) sites are highly desired to facilitate the electrocatalysis industrialization. Nevertheless, the concomitance of metal nanoparticles (NPs) enclosed by graphene layers is commonly inevitable and results in structure heterogeneity. Herein, an electronic structure modulation strategy of inactivating nickel (Ni) NPs to maximize Ni SAs for highly efficient and selective carbon dioxide reduction reaction (CO2RR) within a facilely prepared self-supported Ni NPs/SAs-containing catalyst is reported. The side effect of Ni NPs is effectively inhibited by finely tuning the encapsulating graphene layers thickness to block electrons penetration. The optimized catalyst exhibits a nearly 100% selectivity of CO production under moderate working potentials of -0.6- -0.8 V (vs reversible hydrogen electrode) and produces a partial current density of 341 mA cm(-2) when directly used as a gas diffusion electrode for CO2RR. The authors' discoveries provide fresh insights into the design and scalable preparation of self-supported M-N-C catalysts with unitary single-atom active sites for CO2RR aiming at industrialization.