https://scholars.lib.ntu.edu.tw/handle/123456789/575827
標題: | Silicon microwire arrays decorated with amorphous heterometal-doped molybdenum sulfide for water photoelectrolysis | 作者: | CHIH-JUNG CHEN Yang K.-C Liu C.-W Lu Y.-R Dong C.-L Wei D.-H Hu S.-F Liu R.-S. RU-SHI LIU |
關鍵字: | Catalyst 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 | 公開日期: | 2017 | 卷: | 32 | 起(迄)頁: | 422-432 | 來源出版物: | Nano Energy | 摘要: | Silicon 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 Ltd |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008600512&doi=10.1016%2fj.nanoen.2016.12.045&partnerID=40&md5=f0c8f09f290abbffc70045a10e58a96b https://scholars.lib.ntu.edu.tw/handle/123456789/575827 |
ISSN: | 22112855 | DOI: | 10.1016/j.nanoen.2016.12.045 | SDG/關鍵字: | Catalyst 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 |
顯示於: | 化學系 |
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