A surface science approach to unveiling the TiO2 photocatalytic mechanism: Correlation between photocatalytic activity and carrier lifetime

Kenichi Ozawa, Susumu Yamamoto, Kazuhiko Mase, Iwao Matsuda

Research output: Contribution to journalReview articlepeer-review

1 Citation (Scopus)

Abstract

Establishing an accurate view of the photocatalytic mechanism of titanium dioxide (TiO2) has been a challenging task since the discovery of the Honda-Fujishima effect. Despite the great success of catalytic studies in elucidating the chemical and physical aspects of photocatalysis, many questions remain. A surface science approach, which is characterized by the use of atomically well-defined surfaces in precisely controlled environments, is a powerful tool to shed light on the fundamental mechanism, especially the dynamics of photoexcited carriers. In the present contribution, recent progress in photocatalytic research that correlates photocatalytic activity and carrier dynamics on rutile and anatase TiO2 is reviewed. A special focus is placed on the lifetime of photoexcited carriers. We present a method to determine the carrier lifetime; pump-probe time-resolved soft X-ray photoelectron spectroscopy, utilizing an ultraviolet laser as a pump light and a synchrotron radiation as a probe light. The carrier lifetime is found to be linearly correlated with the photocatalytic decomposition/desorption rate of acetic acid adsorbed on single-crystal TiO2 surfaces. The important role of a potential barrier on the TiO2 surface, which influences the carrier lifetime and the photocatalytic activity, is discussed.

Original languageEnglish
Pages (from-to)130-147
Number of pages18
Journale-Journal of Surface Science and Nanotechnology
Volume17
DOIs
Publication statusPublished - 2019

Keywords

  • Carrier lifetime
  • Photocatalysis
  • Photoelectron spectroscopy
  • Synchrotron radiation
  • Time-resolved measurement

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Condensed Matter Physics
  • Mechanics of Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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