CHIH-JUNG CHENYang K.-CLiu C.-WLu Y.-RDong C.-LWei D.-HHu S.-FRU-SHI LIU2021-08-032021-08-03201722112855https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008600512&doi=10.1016%2fj.nanoen.2016.12.045&partnerID=40&md5=f0c8f09f290abbffc70045a10e58a96bhttps://scholars.lib.ntu.edu.tw/handle/123456789/575827Silicon is a promising photocathode material for solar hydrogen evolution because of its small band gap, negative conduction band position, and ideal theoretical current density. In this study, p-type Si microwire (p-Si MW) arrays were prepared as photocathodes because of the large surface area and high light-harvesting capability. However, Si MWs suffered from low photocatalytic activity because of slow photo-induced carriers during driving of water-splitting reaction. Therefore, molybdenum sulfide (MoS2) with appropriate band alignment with p-Si material was employed for surface modification to function as a co-catalyst for collecting photo-generated minority carriers and reducing recombination possibility. The onset potential and current density at 0 V versus reversible hydrogen electrode (RHE) of Si@MoS2 MWs were +0.122 V and ?8.41 mA cm?2. Heterometal atoms were employed to dope MoS2 co-catalyst and expose more sulfur-terminated active sites to further boost photoelectrochemical performance. Optimal activity of Si@MMoSx (M = Fe, Co, Ni) was achieved by doping Co heteroatoms, and its turn-on voltage and photocurrent density at 0 V (vs. RHE) were respectively increased to +0.192 V and ?17.2 mA cm?2. X-ray absorption spectroscopy was applied to demonstrate that Fe ions of FeMoSx were dichalcogenide materials, forming a composite with MoS2 and contributing better photoelectrolytic efficiency. By contrast, two-valent heteroatoms of CoMoSx and NiMoSx substituted the Mo4+ ions in MoS2. For charge compensation, more defects and edges were revealed as active sites of solar hydrogen production by adding Co or Ni dopants in MoS2 co-catalyst, which led to lower overpotential. ? 2017 Elsevier LtdCatalyst activity; Catalysts; Doping (additives); Energy gap; Field emission cathodes; Hydrogen production; Molybdenum; Molybdenum compounds; Nickel; Photocathodes; Silicon; Solar power generation; Sulfur compounds; Surface treatment; X ray absorption spectroscopy; Co catalysts; Molybdenum sulfide; Silicon microwire; Solar hydrogen; Water splitting; Amorphous silicon[SDGs]SDG7Catalyst activity; Catalysts; Doping (additives); Energy gap; Field emission cathodes; Hydrogen production; Molybdenum; Molybdenum compounds; Nickel; Photocathodes; Silicon; Solar power generation; Sulfur compounds; Surface treatment; X ray absorption spectroscopy; Co catalysts; Molybdenum sulfide; Silicon microwire; Solar hydrogen; Water splitting; Amorphous siliconjournal article10.1016/j.nanoen.2016.12.0452-s2.0-85008600512