Efficient degradation of organic contaminants in aqueous media using oxygen vacancy-rich MnO catalyst via peroxymonosulfate activation

Understanding the role of oxygen vacancies (OVs) in endowing catalytic activity is important for the design of efficient catalysts for advanced oxidation processes. In this study, we prepared MnO catalysts with different amounts of OVs under an atmosphere of H2 (MnO-H) and N2 (MnO-N) and investigated their acetaminophen (ACE) degradation efficiency via peroxymonosulfate (PMS) activation. MnO-H exhibited the best degradation performance because of its numerous OVs, compared with that of MnO-N and the commercial MnO. Data analysis revealed that ACE degradation proceeded via electron transfer. Density functional theory calculations confirmed that compared with the other catalysts, MnO-H/PMS with more OVs had higher catalytic activity, higher adsorption energy, lower work function, and higher electron transformation. The MnO-H/PMS system was stable at pH 3.0–9.0 and showed good recyclability. We believe that our findings will provide deeper insights into the role of OVs and encourage the use of less toxic metal oxides as catalysts in the selective degradation of organic pollutants in water bodies.