High performance n~+p-Si/Ti/NiSxOy photocathode for photoelectrochemical hydrogen evolution in alkaline solution

Silicon, as a promising semiconductor for fabricating photocathode toward photoelectrochemical hydrogen evolution reaction(PEC-HER), should be improved in light harvesting ability and catalytic kinetics to obtain high PEC performance. Herein, a novel amorphous Nickel Oxysulfide(NiSO) film is effectively integrated with a Ti protected n~+p-Si micropyramid photocathode by the electrodeposition method. The fabricated n~+p-Si/Ti/Ni SxOyphotocathode exhibits excellent PEC-HER performance with an onset potential of 0.5 V(at J =-0.1 mA/cm~2), a photocurrent density of-26 mA/cm~2 at 0 V vs. RHE, and long term stability of six hours in alkaline solution(pH ≈ 14). The synergy of unique n~+p-Si micropyramid architectures(omnidirectional broadband light harvesting ability), novel amorphous NiSOcatalyst(high HER electrocatalytic activity and good optical transparency) results in the high performance of n~+pSi/Ti/Ni SO. This work offers a novel strategy for effectively integrating electrocatalysts with semiconductor to design efficient photoelectrode toward PEC water splitting.