Transition-metal-doped NiSe2 nanosheets towards efficient hydrogen evolution reactions

Transition metal diselenides are promising electrocatalysts for hydrogen evolution and therefore different approaches have been proposed to enhance their catalytic activity. Herein, we describe systematic studies of the dependence of transition-metal doping on the catalytic activity of NiSe2 by first principles calculations, where Fe is demonstrated to be the best candidate element to tune the electrocatalytic activity of NiSe2 with lower G(H*) values and increased electrical conductivity. To provide further experimental evidence, Fe-doped NiSe2 porous nanosheets grown on carbon cloth are successfully developed. These nanosheets show significantly improved efficiency for hydrogen evolution reactions compared to their un-doped counterpart. The optimized Ni0.8Fe0.2Se2 electrocatalyst gives rise to a current density of 10 mAcm(-2) at a very low overpotential of 64 mV with outstanding long-term stability. The present strategy of doping NiSe2 -based electrocatalysts with transition metals paves a new pathway for the design and synthesis of electrocatalysts for large-scale electrochemical energy applications.