Bicarbonate-enhanced generation of hydroxyl radical by visible light-induced photocatalysis of H2O2 over WO3: Alteration of electron transfer mechanism

Jaemin Choi, Hak–Hyeon –H Kim, Ki–Myeong –M Lee, Na Chen, Min Sik Kim, Jiwon Seo, Donghyun Lee, Haein Cho, Hyoung il Kim, Jaesang Lee, Hongshin Lee, Changha Lee

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The generation of hydroxyl radical (OH) by visible light-illuminated tungsten oxide (WO3) was found to be significantly improved in the presence of hydrogen peroxide (H2O2) and bicarbonate ion (HCO3). A ternary system of hν/WO3/H2O2/HCO3 showed synergistic enhancement in oxidation of benzoic acid (BA, a OH probe compound) into hydroxybenzoic acids (HBAs), exhibiting even less consumption of H2O2 than hν/WO3/H2O2. Analyses of HBAs from BA oxidation (three HBA isomers and 18O-labelled HBA from H218O2) suggested that hν/WO3/H2O2/HCO3, contrary to hν/WO3/H2O2, generated OH mainly via one-electron transfer from the conduction band of WO3 to H2O2. The dominant one-electron reduction of H2O2 over HCO3-treated WO3 was further evidenced by Koutecký–Levich plots obtained with a rotating disk electrode setup. Based on different experiments using electron paramagnetic resonance spectroscopy, radical scavengers and probes, (photo-)electrochemical measurements, and density functional theory calculations, the mechanisms underlying the enhanced generation of OH by hν/WO3/H2O2/HCO3 were discussed.

Original languageEnglish
Article number134401
JournalChemical Engineering Journal
Volume432
DOIs
Publication statusPublished - 2022 Mar 15

Keywords

  • Bicarbonate
  • Hydrogen peroxide
  • Hydroxyl radical
  • Photocatalysis
  • Tungsten oxide

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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