N-doped carbon polyhedron-modified Co@N-doped carbon nanotube with enhanced 1O2 production for selective removal of organic pollutants

Persulfate-based advanced oxidation process dominated by singlet oxygen ( 1 O 2 ${}^1{\mathrm{O}}_2$ ) shows potential for targeted degradation of organic pollutants but the regulation of 1 O 2 ${}^1{\mathrm{O}}_2$ generation is still challenging. In this study, N-doped carbon polyhedron-modified Co@N-doped carbon nanotube (NCP/Co@NCNT) were successfully fabricated. The as-obtained NCP/Co@NCNT demonstrated a much enhanced 1 O 2 ${}^1{\mathrm{O}}_2$ production in activating peroxymonosulfate (PMS) because of the nanoconfinement effect of metallic Co nanoparticles encapsulated in NCNT, which was further confirmed by density functional theory calculations. The NCP/Co@NCNT/PMS system has excellent catalytic performance and is capable of removing 97 % of carbamazepine (CBZ) in 55 min (Catalyst: 0.1 g/L, CBZ: 20 mg/L, PMS: 0.5 g/L). Quantitative structure–activity relationship (QSAR) analysis uncovered a positive correlation between the oxidation kinetics of organic pollutants and their E HOMO . Specifically, pollutants with higher E HOMO are more easily oxidized in the 1 O 2 ${}^1{\mathrm{O}}_2$ -dominated NCP/Co@NCNT/PMS system. Furthermore, the generated intermediates exhibited low toxicity in the system with 1 O 2 ${}^1{\mathrm{O}}_2$ as the primary active species. This study offers an effective approach to prepare catalysts for the selective elimination of organic micropollutants in complex water environments.