Co nanoparticles regulate atomically dispersed CoN3 sites on carbon to enhanced peroxymonosulfate activation

Nanoparticle incorporation reduces the coordination number of Co-N x while enhancing curvature. • The kinetic rate constant reached 315 min −1  M −1 was achieved at an ultralow PMS concentration. • The PMS complex exhibits excellent oxidation efficiency while maintaining high selectivity. Metal nanoparticles could regulate the electronic structure of single-atom sites in catalysts, thus enhance efficiency in the Fenton-like reactions. However, the effects and mechanisms of nanoparticle existence on both coordination number and curvature of metal sites remains largely overlooked. Herein introducing nanoparticles into catalysts serves as a strategy to modulate catalyst size effect for directional construction of metal sites possessing lower coordination numbers and higher curvature. Theoretical and experimental results reveal that decrease of the coordination number and increase of the curvature of the metal sites boost electron density, unlocking the energetic potential for adsorption in the peroxymonosulfate (PMS) system and highlighting their key function in the regulation of the electronic structure of the metal centers. This effect facilitates highly efficient electron transfer between cobalt atoms and PMS, which promotes the formation of PMS complexes (PMS*). As a result, the catalyst (denoted as Co NPs/Co-N 3 -C) achieved an exceptional k -value of 315 min −1  M −1 in the Fenton-like removal of Bisphenol A (BPA), outperforming the majority of transition-metal catalysts reported in recent years. This study provides a synthetic strategy for catalysts integrating metal single atoms with nanoparticles and elucidates how coordination environment and curvature jointly regulate electronic structure to achieve efficient Fenton-like reactions.