Ni doping modulated adsorption of hydrogen atoms on CoSe 2 electrocatalyst for excellent acid hydrogen evolution by water splitting

CoSe 2 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 CoSe 2 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 CoSe 2 in 0.5 M H 2 SO 4 electrolyte. Density functional theory calculation showed that Ni doping effect in CoSe 2 lattice can decrease the electronic density of Se p-orbital around the Fermi level. The ΔG H* in Se site of Ni-doped CoSe 2 was decreased to 0.196 eV from 0.356 eV (pure CoSe 2 ) 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 CoSe 2 electrocatalyst.