Overlooked role of nitrogen dopant in carbon catalysts for peroxymonosulfate activation: Intrinsic defects or extrinsic defects?

Nitrogen was usually doped into carbon matrix to boost its catalytic activity owing to its electronic adjusting activity toward the topological carbon structure. Herein, an overlooked role of nitrogen dopant was unraveled. The nitrogen dopant was firstly incorporated into the carbon matrix and then partially evaporated, leaving the newly generated topological intrinsic defects under high temperature. It was confirmed that peroxymonosulfate (PMS) could be activated by topological defects-rich carbon catalysts. Surface-activated PMS complex was found to be the dominant reactive oxidation species for organic degradation through electron-transfer mechanism. The distinct current density attenuation revealed that N-rich carbon catalysts possessed more effective stoichiometric reaction between the surface-activated PMS and adsorbed organic than topological defects-rich carbon. Findings from this work confirmed the roles of topological defects and extrinsic defects in PMS activation and provided new insight into the synthesis of defects-rich carbon catalysts.