The Role of Common Alcoholic Sacrificial Agents in Photocatalysis: Is It Always Trivial?

Krishnamoorthy Sathiyan, Ronen Bar-Ziv, Vered Marks, Dan Meyerstein, Tomer Zidki

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Photocatalytic hydrogen production is proposed as a sustainable energy source. Simultaneous reduction and oxidation of water is a complex multistep reaction with high overpotential. Photocatalytic processes involving semiconductors transfer electrons from the valence band to the conduction band. Sacrificial substrates that react with the photochemically formed holes in the valence band are often used to study the mechanism of H2 production, as they scavenge the holes and hinder charge carrier recombination (electron-hole pairs). Here, we show that the desired sacrificial agent is one forming a radical that is a fairly strong reducing agent, and whose oxidized form is not a good electron acceptor that might suppress the hydrogen evolution reaction (HER). In an acidic medium, methanol was found to fulfill both these requirements better than ethanol and propan-2-ol in the TiO2-(M0-NPs) (M=Au or Pt) system, whereas in an alkaline medium, the alcohols exhibit a reverse order of activity. Moreover, we report that CH2(OH)2 is by far the most efficient sacrificial agent in a nontrivial mechanism in acidic media. Our study provides general guidelines for choosing an appropriate sacrificial substrate and helps to explain the variance in the performance of alcohol scavenger-based photocatalytic systems.

Original languageEnglish
Pages (from-to)15936-15943
Number of pages8
JournalChemistry - A European Journal
Volume27
Issue number64
DOIs
StatePublished - 17 Nov 2021

Keywords

  • acetone
  • hydrogen evolution reaction
  • radicals
  • reaction mechanism
  • sacrificial agents

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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