Graphene-oxide-intercalated layered manganese oxides as an efficient oxygen reduction reaction catalyst in alkaline media

Abstract

A graphene-oxide-intercalated layered manganese oxide (GO-HLMO) was prepared by intercalating graphene oxide (GO) into the protonated layered manganese oxide (HLMO,H0.32MnO2), and its enhanced activity towards oxygen reduction reactions (ORR) in alkaline media was demonstrated. As a result of GO intercalation, decreases in interlayer distance and in Mn oxidation state were experimentally confirmed by X-ray diffraction (XRD), X-ray absorption near-edge structure (XANES), and X-ray photoelectron spectroscopic (XPS) analysis. Cyclic voltammetry (CV) analysis indicated that GO-HLMO had more accessible Mn( III)/Mn(IV) sites than HLMO, which probably resulted in the large enhancement in ORR activity in alkaline media, from 0.236 A g(-1) (HLMO) to 0.735 A g(-1) (GO-HLMO) at 0.8 V vs. RHE.