Postsynthesis oxygen nonstoichiometric regulation: a new strategy for performance enhancement of perovskites in advanced oxidation

Abstract

Due to their flexible physiochemical properties and defect-rich structures, perovskite oxides have drawn increasing attention as efficient heterogeneous catalysts for peroxymonosulfate (PMS) activation in wastewater remediation. Herein, we reported a new nondoping strategy of postsynthesis oxygen nonstoichiometric regulation for LaMnO₃₊δ (LMO) at various oxygen partial pressures and calcination temperatures, named as LMO-P-T, to control its interstitial oxygen defect content, resulting in the enhancement of its catalytic activity and stability for degradation of rhodamine B (RhB). The defect structure, charge-transfer capacity, and resistance against metal leaching of LMO were thus improved. Specifically, LMO-5 bar-600 with the highest defect content presented excellent Fenton-like activity, 1.76 times that of LMO. Favorable singlet oxygen was confirmed as the dominant reactive species in the LMO-5 bar-600/PMS system, and the obtained catalysts showed satisfactory activity in a wide initial pH range. This work might provide a universal approach in designing metal oxides catalysts for efficient advanced oxidation.