Mn3O4 nanoparticles on layer-structured Ti3C2 MXene towards the oxygen reduction reaction and zinc–air batteries

Abstract

Non-precious metal catalysts, such as manganese oxide (Mn₃O₄), with efficient activity and superior stability are highly required. However, poor conductivity, dissolution, and high cohesion significantly limit the performance of Mn₃O₄ nanoparticles as an electrode material. Herein, Mn₃O₄ nanoparticles supported on layered Ti₃C₂ MXene (Mn₃O₄/MXene) nanocomposite with superb oxygen reduction reaction performance have been reported for the first time. The as-prepared Mn₃O₄/MXene nanocomposite display favorable electrochemical activity in oxygen reduction reaction with a dominant four-electron oxygen reduction pathway and an onset potential at 0.89 V (same as that of Pt/C) in an alkaline solution. Layered MXenes exhibit metal conductivity as well as hydrophilicity, which would greatly improve the chemical properties of the nano-sized particles by inhibiting aggregation and increasing the electron transfer speed. Furthermore, Mn₃O₄/MXene exhibits higher stability than Mn₃O₄/acetylene black owing to the highly stable Mn₃O₄/MXene hybrid structure. The as-prepared Zn–air battery based on the Mn₃O₄/MXene air-cathode exhibits a high open potential (1.37 V), superb power density (150 mW cm⁻²), and excellent stability (no obvious potential change in 100 hours). The prepared low-cost Mn₃O₄/MXene nanocomposite with superior oxygen reduction reaction performance can be a promising candidate as an oxygen reduction reaction catalyst and for use in zinc–air batteries and other energy storage devices.