Amorphous Phosphorus-Doped Cobalt Sulfide Modified on Silicon Pyramids for Efficient Solar Water Reduction

Chih Jung Chen, Chi Wei Liu, Kai Chih Yang, Li Chang Yin, Da Hua Wei, Shu Fen Hu, Ru Shi Liu

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Cobalt sulfide (CoSx) functioned as a co-catalyst to accelerate the kinetics of photogenerated electrons on Si photocathode, leading to the enhancement of solar hydrogen evolution efficiency. By doping phosphorus heteroatoms, CoSx materials showed an improved catalytic activity because of superior surface area and quantity of active sites. Furthermore, increased vacancies in unoccupied electronic states were observed, as more phosphorus atoms doped into CoSx co-catalysts. Although these vacant sites improved the capability to accept photoinduced electrons from Si photoabsorber, chemisorption energy of atomic hydrogen on catalysts was the dominant factor affecting in photoelectrochemical performance. We suggested that P-doped CoSx with appropriate doping quantities showed thermoneutral hydrogen adsorption. Excess phosphorus dopants in CoSx contributed to excessively strong adsorption with H atoms, causing the poor consecutive desorption ability of photocatalytic reaction. The optimal P-doped CoSx-decorated Si photocathode showed a photocurrent of -20.6 mA cm-2 at 0 V. Moreover, a TiO2 thin film was deposited on the Si photocathode as a passivation layer for improving the durability. The current density of 10 nm TiO2-modified photocathode remained at approximately -13.3 mA cm-2 after 1 h of chronoamperometry.

Original languageEnglish
Pages (from-to)37142-37149
Number of pages8
JournalACS Applied Materials and Interfaces
Volume10
Issue number43
DOIs
Publication statusPublished - 2018 Oct 31

Keywords

  • P-doped cobalt sulfide
  • Si pyramids
  • co-catalyst
  • hydrogen evolution reaction
  • water reduction

ASJC Scopus subject areas

  • Materials Science(all)

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