Facile preparation of 3D MoS2/MoSe2 nanosheet-graphene networks as efficient electrocatalysts for the hydrogen evolution reaction

In this paper, 3D porous MoS2/MoSe2 nanosheet-graphene networks were successfully prepared by a simple mixing solvothermal treatment. The resulting products possessed highly conductive graphene networks on which highly exfoliated MoS2/MoSe2 nanosheets were decorated. This hybrid 3D architecture facilitated loading of 2D nanosheets (including some 0D quantum dots), exposure of active sites, and improvement of electron transfer between the electrode and the catalysts. The highly exfoliated and defect-rich structure of MoS2/MoSe2 nanosheets endowed these composites with plentiful active sites for the electrocatalysis of the hydrogen evolution reaction (HER). The MoSe2 sample exhibited remarkable activity for the HER with a very small overpotential of approximately 70 mV and a low Tafel slope of 61 mV per dec, as well as excellent long-term durability. Moreover, due to the facile and relatively low-cost preparation method, our work might develop promising candidates for Pt-free HER catalysts for future commercial applications and provide an alternative facile approach to fabricate other layered materials confined in graphene hybrid 3D networks on a large scale.