Hierarchical nanostructures of MgCo2O4 on reduced graphene oxide as a high-performance catalyst for methanol electro-oxidation

Abstract

A flower-like binary transition metal oxide, in the form of MgCo2O4, was successfully synthesized and investigated by XRD and Raman spectroscopy as well as by SEM and TEM micrographs. A hybrid of MgCo2O4 with reduced graphene oxide (rGO) was prepared to distinguish between the rGO-riched and rGO-free catalysts for potential applications in direct methanol fuel cell (DMFC) anodes (methanol electro-oxidation process). The synergetic effect due to the proximity of magnesium and cobalt oxides, along with their hybridization on the rGO, makes MgCo2O4-rGO an efficient and low-cost catalyst for an anode electrode in the DMFC applications. EIS, CV, LSV tests, and cyclic stability of MgCo2O4-rGO for 2000 subsequent CV cycles confirm the pivotal role of rGO in the catalyst structure. Finally, the single-cell test indicated the suitability of our proposed catalyst for practical applications of DMFC. Indeed, the single-cell polarization diagrams show a significantly improved power density for single cells with MgCo2O4-rGO-based anode (19 mW cm−2) compared to MgCo2O4- based anode (11 mW cm−2).