Cu@S-Co(OH)2 hybrid electrocatalysts with high performance for alkaline hydrogen evolution reaction

Abstract

Transition metal hydroxides have superior oxygen evolution reaction (OER) activity but poor hydrogen evolution reaction (HER) performance, which greatly limits the water splitting for hydrogen production. Herein, copper modification of sulfur doped Co(OH)2 hybrid catalyst (Cu@S-Co(OH)2) was prepared by one-step of electrodeposition method which can serve as efficient hydrogen evolution reaction catalyst. In the presence of sulfur and copper, Cu@S-Co(OH)2 hybrid catalyst exhibits the best catalytic activity, showing ultralow overpotential of 42 mV at a current density of 10 mA cm−2. Compared with Co(OH)2, the overpotential is improved by nearly 100 mV as well as enhanced stability. In addition, the active site poison experiments proved that the active center is cobalt metal. Combined with the adsorption strength of the catalyst for OH and H species, it is considered that both S and Cu can enhance the adsorption of OH for Co(OH)2, while S is contributed to the adsorption of H, and Cu can promote the desorption of H. This work provides a facile method and new insight to enhance the HER activity for transitional metal hydroxides via metal and non-metallic elements co-modulation.