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Proceedings Paper

Photoinduced redox reaction of carboxylates on TiO2(110)
Author(s): J. M. White; Michael A. Henderson; Hiroshi Uetsuka; Hiroshi Onishi
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Paper Abstract

The adsorption and ultraviolet photolysis at 300 K of trimethylacetate, (CH3)3CCOO-, on TiO2(110) has been explored by combining scanning tunneling microscopy, isothermal reaction mass spectrometry and electron energy loss spectroscopy. The photolysis, initiated by forming excited electrons and holes in the oxide, is dominated by ejection of CO2 and C4H8 with no evidence for retention of carbon-containing species. The chemistry is the result of holes extracting electron density from the pi-orbital of a carboxyl group leading to decarboxylation. The accompanying electron is trapped as Ti3+ at the surface. These trapped species compete for holes and inhibit the hole-mediated decarboxylation. The trapped electrons can be removed by exposure to O2 at 300 K leading to a transient acceleration of the reaction rate after resuming photolysis. Under aerobic conditions, arriving O2 scavenges trapped electrons as they are formed reducing the degree of quenching and increasing the rate of trimethylacetate consumption without changing the products.

Paper Details

Date Published: 14 October 2004
PDF: 10 pages
Proc. SPIE 5513, Physical Chemistry of Interfaces and Nanomaterials III, (14 October 2004); doi: 10.1117/12.558940
Show Author Affiliations
J. M. White, Pacific Northwest National Lab. (United States)
Univ. of Texas/Austin (United States)
Michael A. Henderson, Pacific Northwest National Lab. (United States)
Hiroshi Uetsuka, Kanagawa Academy of Science and Technology (Japan)
Hiroshi Onishi, Kanagawa Academy of Science and Technology (Japan)

Published in SPIE Proceedings Vol. 5513:
Physical Chemistry of Interfaces and Nanomaterials III
Gregory V. Hartland; Xiao-Yang Zhu, Editor(s)

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