Aeration-Free Photo-Fenton-Like Reaction Mediated by Heterojunction Photocatalyst toward Efficient Degradation of Organic Pollutants.

Abstract

The regulation of peroxymonosulfate (PMS) activation by photo-assisted heterogeneous catalysis is under in-depth investigation with potential as a replaceable advanced oxidation process in water purification, yet it remains a significant challenge. Herein, we demonstrate a strategy to construct polyethylene glycol (PEG) well-coupled dual-defect V_O-M-Co₃O₄@CN_x S-scheme heterojunction to degrade organic pollutants without aeration, which dramatically provides abundant active sites, excellent photo-thermal property, and distinct charge transport pathway for PMS activation. The degradation rate of V_O-M-Co₃O₄@CN_x in anaerobic conditions shows a higher efficient rate (4.58 min^-1 g^-2) than in aerobic conditions (1.67 min^-1 g^-2). Experimental evidence reveals that V_O-M-Co₃O₄@CN_x promotes more rapid redox conversion of photoexcited electrons induced by defects with PMS under anaerobic conditions compared to aerobic conditions. Additionally, in situ experiments and DFT provide mechanistic insights into the regulation pathway of PMS activation via synergistic defect-induced electron, revealing the competitive effect between O₂ and PMS over V_O-M-Co₃O₄@CN_x during the reaction process. The continuous flow reactor and flow cytometry results demonstrated that the V_O-M-Co₃O₄@CN_x/PMS/Vis system has remarkably enhanced stability and purification capability for removing organic pollutants. This work provides valuable insights into regulating the heterologous catalysis oxidation process without aeration through the photoexcitation synergistic PMS activation.