Ni doping modulated adsorption of hydrogen atoms on CoSe2 electrocatalyst for excellent acid hydrogen evolution by water splitting

CoSe2 nanostructure was regarded as an excellent electrocatalyst for hydrogen evolution reaction by water splitting owing to its particular electronic configuration. Herein, Ni atoms doped in CoSe2 nanowire arrays was fabricated on carbon fiber paper substrate by two-step hydrothermal routes and subsequent heat treatment. Both common transient analysis, steady-state analysis, and TOF and EIS measurements confirmed that Ni doping effect could significantly enhance the HER performance of CoSe2 in 0.5 M H2SO4 electrolyte. Density functional theory calculation showed that Ni doping effect in CoSe2 lattice can decrease the electronic density of Se p-orbital around the Fermi level. The ΔGH* in Se site of Ni-doped CoSe2 was decreased to 0.196 eV from 0.356 eV (pure CoSe2) because the empty orbital of Se sites could strengthen the adsorption of H atoms. Finally, Ni doping effect provides an effective method for improved HER activity of CoSe2 electrocatalyst.