Microwave and template assisted synthesis of atomically dispersed Co-N₂ sites on carbon spheres for Fenton-like reaction

Recently, single atomic metals supported on carbon materials have attracted great interests because of their high catalytic activity and stability in peroxymonosulfate (PMS)-based Fenton-like process. Herein, we propose a convenient strategy to synthesize Co single atoms supported on nitrogen-doped carbon spheres (Co@MNC) via microwave treatment. The microwave irradiation can simultaneously induce the formation of carbon defects and immobilize the Co single atoms in N doped carbon support in a few minutes. The obtained Co@MNC can activate PMS for efficient catalytic oxidation of organic pollutants. The radical quenching tests and electron paramagnetic resonance (EPR) verify that Co (IV)-oxo species, O-1(2), and O-2(center dot-) are responsible for the remediation of organic pollutants. Density functional theory (DFT) calculations confirm that unique and low coordinated Co-N-2 on void or edge defects are favorable for PMS adsorption. The electrons will then transfer from Co atoms to adsorbed PMS via the bonded N. Co (IV)-oxo species and other ROSs are therefore generated for pollutants degradation. This work provides a fast method for the synthesis of single atom catalysts for efficient Fenton-like reactions.