Electronic Structure Reconfiguration of Zn-N_xB_{4- x} Sites for Enhanced Fenton-Like Catalysis

Despite growing interest in single-atom catalysts (SACs) for Fenton-like reactions, zinc (Zn)-based SACs remain unexplored due to the inherent inertness of Zn²⁺, whose fully occupied 3d¹⁰ electronic configuration limits redox activity. Here, we overcome this limitation by introducing boron (B) atoms to reconfigure the electronic structure of Zn-N₄ coordination sites, yielding an activated catalyst denoted as Zn-NBC. This electronic modulation transforms inert Zn-N₄ sites into catalytically active centers (Zn-N_xB_{4- x}), enabling significantly enhanced Fenton-like activity. Compared to the unmodified Zn-N₄ catalyst (Zn-N₄C), Zn-NBC exhibits a 26-fold increase in the rate of organic pollutant degradation. Density functional theory (DFT) calculations and experimental results reveal that Zn-N₄C and Zn-NBC exhibit distinct PDS adsorption behaviors, with B incorporation tuning both adsorption strength and electronic interactions at the Zn center. Crystal orbital Hamilton population (COHP) analysis further demonstrates that the Zn-NBC facilitates the activation of the S─O bonds in peroxydisulfate (PDS), promoting the generation of reactive oxygen species, including peroxide radicals and singlet oxygen. These findings establish a new paradigm for activating electronically inert metal centers and position Zn-NBC as a promising platform for efficient and sustainable environmental remediation.