MOF-reduced Graphene Oxide Composites with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

Abstract

Development of inexpensive and scalable cathode catalysts that can efficiently catalyze the oxygen reduction reaction (ORR) is of significance in practical application of fuel cells. The oxygen reduction activity of the MOF-based catalyst is much lower than that of Pt, which is mainly due to the high overpotential. In this work, we designed a superior composite named Co@Co3O4-reduced graphene oxide (Co@Co3O4-rGO) derived from MOF-rGO by an in-situ synthetic method which gathered both the advantages of MOF and rGO. The Co2+ which belongs to the MOF provides the metal source, while the N sources are supplied by the organic ligands benzimidazole. With the combination of rGO, Co@Co3O4-rGO has got a higher specific surface area and much better transport pathways for oxygen and the electrolyte than Co@Co3O4-C derived from the pure MOF. The half-wave potential, onset potential of Co@Co3O4-rGO are close to the superior commercial Pt/C catalyst. The number of electron transfer in the process of catalytic oxygen reduction is close to 4, the excellent properties benefited from the synergistic effect of rGO and MOF.