N-doped carbon polyhedron-modified Co@N-doped carbon nanotube with enhanced [formula omitted] production for selective removal of organic pollutants

Abstract

Persulfate-based advanced oxidation process dominated by singlet oxygen (1O2) shows potential for targeted degradation of organic pollutants but the regulation of 1O2 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 1O2 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 EHOMO. Specifically, pollutants with higher EHOMO are more easily oxidized in the 1O2-dominated NCP/Co@NCNT/PMS system. Furthermore, the generated intermediates exhibited low toxicity in the system with 1O2 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.