NiSe2 nanocrystals anchored graphene nanosheets as highly efficient and stable electrocatalyst for hydrogen evolution reaction in alkaline medium

Abstract

A NiSe2/reduced graphene oxide (rGO) hybrid, constructed by NiSe2 nanocrystals homogeneously anchored on the rGO nanosheets, is fabricated through a facile one-step low-temperature solvothermal synthesis. Compared with the bare NiSe2 counterpart, the NiSe2/rGO hybrid delivers much better hydrogen evolution reaction (HER) performance with a low Tafel slope of 68.8 mV dec−1 and low onset potential of −149 mV in 1 M KOH. In addition, the overpotential of the hybrid for 120 mA cm−2 is only 404 mV, which is comparable to that of Pt/C catalyst (375 mV). Moreover, the alkaline electrocatalytic activity of the NiSe2/rGO hybrid is stable even after testing for 20 h. The outstanding electrocatalytic activity and high stability of NiSe2/rGO hybrid are in close link with its unique structure: NiSe2 nanocrystals with uniform crystal size are evenly distributed and coherently anchored on the two-dimensional matrix of rGO nanosheets, resulting in significant increase in electrochemical surface area and the number of catalytic active sites; the rGO nanosheets constitute a highly conductive network to facilitate the charge transfer. This work presents a high-efficiency, stable and cost-effective electrocatalyst for HER in alkaline medium.