Oxygen vacancies modified MnS/MnO2 heterostructure anode catalyst for efficiently electrocatalytic removal of dye wastewater

Electrochemical advanced oxidation processes (EAOPs) are favorable technologies to remove organic wastewater, but the development of high-efficiency and low-energy consumption anode catalysts is still a priority. Herein, a carbon cloth-supported MnS/MnO2 heterostructure rich in oxygen vacancies is successfully synthesized as an anode for the electrocatalytic removal of methyl orange (MO) wastewater. The anode catalyst possesses lower charge transfer resistance (77.4 Ω), higher oxygen evolution potential (2.13 V vs RHE), and removes nearly 100% methyl orange (20 mg/L) in 30 min with a high mineralization current efficiency of 73.2% and low energy consumption of 23.4 kWh/kg TOC. Through density functional theory (DFT) studies, oxygen vacancies increase the positive charge of Mn atoms in the vicinity of the heterostructure interface, thus improving its catalyst activity. The calculated adsorption energy of H2O (ΔEH2O) is reduced from − 0.672 eV for MnO2 to − 0.887 eV for oxygen-vacancy heterostructure, which is conducive to the water splitting to form •OH. Overall, this study provides a promising strategy for enhancing the electrocatalytic removal performance of manganese dioxide by using heterostructure design and oxygen vacancy engineering.