Self‐reconstruction‐induced c‐CoSe 2 coupled with co( OH ) 2 from Co 0. 85 Se For efficient HER Electrocatalysis in alkaline media

The design of hybrid structures for catalysts toward alkaline hydrogen evolution reaction (HER) is a significant strategy to promote its reaction kinetics. Herein, we synthesize cubic CoSe2 and Co(OH)2 (c-CoSe2@Co(OH)2) hybrid catalysts from the self-reconstruction of flower like Co0.85Se via a simple hydrothermal method accompanied by the addition of NaOH. This strategy is conducive to the distinct enhancement in HER catalytic activity, featuring the lower overpotential of 156 mV at the current density of 10 mA cm−2 than that of Co0.85Se (288 mV). The integrative techniques were used to analyze the reason of activity improvement for the hybrid catalysts. The ultraviolet photoelectron spectroscopy (UPS) analysis demonstrates that the catalyst c-CoSe2@Co(OH)2 possesses good conductivity and the stronger ability to donate electrons. Besides, the DFT calculations reveal that the lower values of ∆ G H 2 O (water dissociation) and ΔGH* (hydrogen adsorption) accompanied by the downshifted d-band center effectively improve the kinetics of HER activity. All of these demonstrate that the derived c-CoSe2@Co(OH)2 hybrid from self-reconstruction of the Co0.85Se obtain modulated electronic structure and improved conductivity effectively enhancing the catalytic activity.