CoN₁O₂ Single‐Atom Catalyst for Efficient Peroxymonosulfate Activation and Selective Cobalt(IV)=O Generation

Abstract High‐valent metal‐oxo (HVMO) species are powerful non‐radical reactive species that enhance advanced oxidation processes (AOPs) due to their long half‐lives and high selectivity towards recalcitrant water pollutants with electron‐donating groups. However, high‐valent cobalt‐oxo (Co IV =O) generation is challenging in peroxymonosulfate (PMS)‐based AOPs because the high 3d‐orbital occupancy of cobalt would disfavor its binding with a terminal oxygen ligand. Herein, we propose a strategy to construct isolated Co sites with unique N 1 O 2 coordination on the Mn 3 O 4 surface. The asymmetric N 1 O 2 configuration is able to accept electrons from the Co 3d‐orbital, resulting in significant electronic delocalization at Co sites for promoted PMS adsorption, dissociation and subsequent generation of Co IV =O species. CoN 1 O 2 /Mn 3 O 4 exhibits high intrinsic activity in PMS activation and sulfamethoxazole (SMX) degradation, highly outperforming its counterpart with a CoO 3 configuration, carbon‐based single‐atom catalysts with CoN 4 configuration, and commercial cobalt oxides. Co IV =O species effectively oxidize the target contaminants via oxygen atom transfer to produce low‐toxicity intermediates. These findings could advance the mechanistic understanding of PMS activation at the molecular level and guide the rational design of efficient environmental catalysts.