Mn3O4 Supported on Glassy Carbon: An Active Non-Precious Metal Catalyst for the Oxygen Reduction Reaction

Abstract

In this work, we explore the interplay between manganese oxide (MnOx) nanomaterials and a glassy carbon (GC) support in catalyzing the oxygen reduction reaction (ORR) in an alkaline environment. Initially, we characterize the ORR activity of bare GC electrodes as a function of heat treatments in air, and find that ORR activity increases with increasing temperature up to 500 °C. Modification of GC with size-selected 1 nm MnOx nanoparticles prior to the 500 °C heat treatment yields a highly porous GC (pGC) structure, devoid of MnOx. This pGC sample exhibits the highest ORR performance of the bare carbon electrodes reaching an onset potential of 0.75 V vs the reversible hydrogen electrode (RHE) and a complete 2-electron reduction of oxygen to peroxide. Having established ORR activity of bare GC electrodes, we deposit size-selected 14 nm MnO nanoparticles onto the GC and pGC electrodes and then incite phase changes in MnO through heat treatments in air. Electrochemical characterization of the resulting electr...