Photoinduced redox reaction of carboxylates on TiO2(110)

J. M. White; Michael A. Henderson; Hiroshi Uetsuka; Hiroshi Onishi

doi:10.1117/12.558940

14 October 2004 Photoinduced redox reaction of carboxylates on TiO₂(110)

J. M. White, Michael A. Henderson, Hiroshi Uetsuka, Hiroshi Onishi

Proceedings Volume 5513, Physical Chemistry of Interfaces and Nanomaterials III; (2004) https://doi.org/10.1117/12.558940
Event: Optical Science and Technology, the SPIE 49th Annual Meeting, 2004, Denver, Colorado, United States

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.

Citation Download Citation

J. M. White, Michael A. Henderson, Hiroshi Uetsuka, and Hiroshi Onishi "Photoinduced redox reaction of carboxylates on TiO₂(110)", Proc. SPIE 5513, Physical Chemistry of Interfaces and Nanomaterials III, (14 October 2004); https://doi.org/10.1117/12.558940

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