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Article
In situ IR study of adsorbed species and photogenerated electrons during photocatalytic oxidation of ethanol on TiO2
Journal of Catalysis
  • Zhiqiang Yu, The University Of Akron
  • Steven Chuang, The University of Akron
Document Type
Article
Publication Date
2-15-2007
Abstract
The reaction pathways for the photocatalytic oxidation of ethanol on the TiO2 surface at 30 °C were studied by in situ infrared (IR) spectroscopy. The coverage of ethanol and water was found to play a key role in how the reaction is initiated. The low ethanol coverage on the H2Oad-containing TiO2 surface produced adsorbed formate (HCOO−ad) as a primary intermediate; the high ethanol coverage on the H2Oad-deficient TiO2 surface produced adsorbed acetate (CH3COO−ad) as a major intermediate during the initial period (i.e., 2 min) of the photocatalytic oxidation. The adsorbed species and reaction products observed during in situ IR studies suggest the low-coverage ethanol reaction is initiated by •OH, whereas the high-coverage ethanol reaction is initiated by hole. The hole-initiating ethanol oxidation on the H2Oad-deficient TiO2 surface produced adsorbed acetic acid (CH3COOHad)/CH3COO−ad, and built up photogenerated electrons, giving a parallel increase in the IR intensity of CH3COO−ad and the IR background at 2000 cm−1 (i.e., a measure of photogenerated electrons). As the high-coverage ethanol reaction proceeded toward producing CO2/H2O, adsorbed H2O accumulated and the coverage of CH3CH2OHad/CH3CH2Oad decreased on the TiO2 surface, shifting the reaction from hole-initiating to •OH-initiating.
Citation Information
Zhiqiang Yu and Steven Chuang. "In situ IR study of adsorbed species and photogenerated electrons during photocatalytic oxidation of ethanol on TiO2" Journal of Catalysis Vol. 246 Iss. 1 (2007) p. 118 - 126
Available at: http://works.bepress.com/steven_chuang/19/