There has been considerable research to engineer composites of transition metal dichalcogenides with other materials to improve their catalytic performance. In this work, we present a modified solution-processed method for the formation of molybdenum selenide (MoSe₂) nanosheets and a facile method of structuring composites with graphene oxide (GO) or reduced graphene oxide (rGO) at different ratios to prevent aggregation of the MoSe₂ nanosheets and hence improve their electrocatalytic hydrogen evolution reaction performance. The prepared GO, rGO, and MoSe₂ nanosheets were characterized by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The electrocatalytic performance results showed that the pure MoSe₂ nanosheets exhibited a somewhat high Tafel slope of 80 mV/dec, whereas the MoSe₂-GO and MoSe₂-rGO composites showed lower Tafel slopes of 57 and 67 mV/dec at ratios of 6:4 and 4:6, respectively. We attribute the improved catalytic effects to the better contact and faster carrier transfer between the edge of MoSe₂ and the electrode due to the addition of GO or rGO.

Transition metal dichalcogenides (TMDs) have been considered as one of the most promising electrocatalysts for the hydrogen evolution reaction (HER). Many studies have demonstrated the feasibility of significant HER performance improvement of TMDs by constructing composite materials with Ni-based compounds. In this work, we prepared Ni₃Se₄@MoSe₂ composites as electrocatalysts for the HER by growing in situ MoSe₂ on the surface of Ni₃Se₄ nanosheets. Electrochemical measurements revealed that Ni₃Se₄@MoSe₂ nanohybrids are highly active and durable during the HER process, which exhibits a low onset overpotential (145 mV) and Tafel slope (65 mV/dec), resulting in enhanced HER performance compared to pristine MoSe₂ nanosheets. The enhanced HER catalytic activity is ascribed to the high surface area of Ni₃Se₄ nanosheets, which can both efficiently prevent the agglomeration issue of MoSe₂ nanosheets and create more catalytic edge sites, hence accelerate electron transfer between MoSe₂ and the working electrode in the HER. This approach provides an effective pathway for catalytic enhancement of MoSe2 electrocatalysts and can be applied for other TMD electrocatalysts.