Features of the Application of Promising Catalysts from Amorphous Molybdenum Sulfide in the Creation of p-Si and pn-Si Photocathodes for the Production of Hydrogen in an Acidic Solution

Abstract—The chemical state of MoS_x catalytic layers and interfaces with p-type silicon (p-Si) and p–n-junction silicon (pn-Si) at various stages of preparation and operation of photocathodes is studied. The SiO_x oxide layer formed at the interface noticeably suppresses the photocurrent for p-Si cathodes, but its removal in the HF solution provides high photocurrents exceeding the values characteristic of pn-Si cathodes at zero potential. Studies of the energy bands show that, at all stages (after the formation of the photocathode, pre- and post-processing in acid solutions), the configuration of the energy bands for p-Si and pn-Si photocathodes provides charge transfer for the evolution of hydrogen according to the Z-scheme. The difference in the characteristics of p-Si and pn-Si photocathodes is due to the possible dependence of the photovoltage in the surface layer of p-Si on the state of the interface with the catalyst film, which does not affect the photovoltage in pn-Si.