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 waste-water, 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 syn-thesized as an anode for the electrocatalytic removal of methyl orange (MO) wastewater. The anode catalyst possesses lower charge transfer resistance (77.4 Omega), 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 (Delta EH2O) 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 center dot 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.(c) 2023 Published by Elsevier B.V.

Automated summary

Electrochemical advanced oxidation processes (EAOPs) are effective in removing organic waste-water, but improved anode catalysts are needed. In this study, a MnS/MnO2 heterostructure with oxygen vacancies supported by carbon cloth was synthesized, which showed lower charge transfer resistance and higher oxygen evolution potential. The catalyst achieved nearly 100% removal of methyl orange in 30 minutes with high mineralization current efficiency and low energy consumption. Oxygen vacancies increased the positive charge of Mn atoms, enhancing the catalyst activity. The study provides a promising strategy for improved electrocatalytic removal of manganese dioxide.