Hydrocarbon decomposition on a hydrophilic TiO2 surface by UV irradiation: Spectral and quantitative analysis using in-situ XPS technique

Naofumi Ohtsu, Naoya Masahashi, Yoshiteru Mizukoshi, Kazuaki Wagatsuma

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

Abstract

This paper presents valuable evidence in support of the removal of a contaminant hydrocarbon layer adsorbed on photocatalytic TiO2 film by the latter's photo-oxidization. UV light was radiated on an anodic TiO 2 film in an atmosphere-controlled chamber, and the film was then transferred to an ultrahigh-vacuum chamber for X-ray photoelectron spectroscopic (XPS) analysis; during the transfer, care was taken to ensure that the film was not exposed to air. This "in situ" setting eliminates the influence of carbon and water adsorptions during the transfer, thus enabling the accurate analysis of the UV-induced surface reaction. The spectral and quantitative results clearly revealed that the adsorbed hydrocarbon was removed from the photocatalytic TiO2 film when the film was irradiated in an oxygen atmosphere. Such removal occurs only in the case of TiO2 films that exhibit superhydrophilicity. This indicates that the removal of hydrocarbon is dependent on the UV-induced hydrophilicity on the film. In situ XPS measurement also presented evidence for UV-induced hydroxide group adsorption, where the adsorption was observed on both the surfaces showing superhydrophilicity and devoid of it.

Original languageEnglish
Pages (from-to)11586-11591
Number of pages6
JournalLangmuir
Volume25
Issue number19
DOIs
Publication statusPublished - 2009 Oct 6

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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