Indium-doped ?-MnO2 catalyst for activation of peroxymonosulfate to generate singlet oxygen with complete selectivity

Singlet oxygen (1O2) has been regarded as an excellent active species for the effective degradation of pollutants. However, generating 1O2 with high selectivity still remains a significant challenge. Herein, 1O2 generation of 100% selectivity for peroxymonosulfate (PMS) activation was achieved by a strategy of indium-doped beta-MnO2 catalyst, affording a dimethyl phthalate degradation rate of 93% within 180 min. Indium active sites served as the active center of the PMS adsorption, and the redox cycling of indium among different valances promoted PMS activation by breaking S-O bond. Density functional theory calculation results demonstrated that HSO5-could be easily adsorbed at indium site to generate 1O2 via effective electron transfer. The indium active sites and oxygen vacancies jointly regulated the PMS decomposition by a non-radical pathway with simultaneous 1O2 generation. This work developed a novel indium-doped beta-MnO2 catalyst for complete selective generation of 1O2 for highly efficient degradation of pollutants.