Enhanced oxygen reduction activity of α-MnO₂ by NH₃ plasma treatment

Abstract

Oxygen vacancies and heteroatom doping play important role in oxygen reduction activity of metal oxides. Developing efficient modification method is one of the key issues in catalysts research. Room temperature plasma treatment, with the advantages of mild working conditions, no emissions and high efficiency, is a new catalyst modification method developed in recent years. In this work, hydrothermal synthesized α-MnO2 nanorods are treated in NH3 plasma at room temperature. In the reducing atmosphere, oxygen vacancies and N doping are achieved simultaneously on the surface. The NH3 plasma etched MnO2 demonstrate a significant enhanced oxygen reduction activity with half-wave potential of 0.84 V, limiting current density of 6.32 mA cm-2 and transferred electrons number of 3.9. The Mg-air battery with N-MnO2 display a maximum power density of 76.3 mW cm-2 as well as stable discharge performance. This work provides new ideas for preparing efficient and cost-effective method to boost the catalysts activity.