Cobalt-doped edge-rich MoS2/nitrogenated graphene composite as an electrocatalyst for hydrogen evolution reaction

Abstract

Co-doped MoS2/nitrogenated graphene composite has been successfully fabricated through a facile hydrothermal method and is investigated as an electrocatalyst for hydrogen evolution reaction (HER). The results reveal that Co2+ ions have been successfully incorporated into MoS2 lattice which can give rise to structural strain and dislocation. As a result, the Co-doped MoS2 nanosheets are characteristic of few layers (3–6 layers) and abundant exposed active edges. Meanwhile, Co-doped MoS2 nanosheets are well implanted into the nitrogen-doped graphene networks to form robust composite. When evaluated as a catalyst for HER, the obtained composite demonstrates superior electrocatalytic activities towards HER including low onset potential (∼90mV), large cathodic current density and small Tafel slope of 59mV dec−1. It is believed that the desirable catalytic properties can be credited to the unique microstructures including few-layer features, plentiful exposed active sites as well as intimate integration with highly electroconductive nitrogenated graphene.