Bimetallic CoZn-MOF nanosheets derived two dimensional Co single-atom catalysts for efficient oxygen reduction

Two-dimensional (2D) materials have gained significant attention as ideal templates for constructing single-atom catalysts (SACs), which maximizes the exposure of active sites and ensures uniform dispersion of metal atoms. Herein, a novel two-dimensional (2D) CoZn-MOF nanosheet was synthesized, which was used as a precursor to construct a N-doped carbon catalyst modified with Co single atoms (Co SAs-NC). During the calcination process, the nitrogen atoms in ligands were converted into a N-doped carbon matrix, effectively anchoring Co ions and generating uniformly distributed Co-Nx active sites. Co SAs-NC exhibited superior ORR performance compared to Pt/C, with a half-wave potential of 0.886 V. Additionally, zinc-air batteries (ZABs) based on Co SAs-NC exhibit a peak power density of 134 mW cm−2, significantly exceeding that of Pt/C (89 mW cm−2). The completion of this work will provide new insights into developing efficient 2D carbon-based non-precious metal ORR catalysts. •A 2D cobalt single atom N-doped carbon material Co SAs-NC was obtained by pyrolysis of 2D dimetallic CoZn-MOF nanosheets.•The 2D precursor MOF provides favorable conditions for the formation of uniformly dispersed Co-Nx active sites.•The 2D layered structure improves the accessibility of active sites, making it easier for reactant molecules to contact the active centers.•The Co SAs-NC demonstrates the highest oxygen reduction activity with a half-wave potential of 0.886 V.