Evaluation of electron–hole recombination properties of titanium(IV) oxide particles with high photocatalytic activity

• Murakami, Shin-Ya

• Kominami, Hiroshi

• Kera, Yoshiya

• Ikeda, Shigeru

• Noguchi, Hidenori

• Uosaki, Kohei

• Ohtani, Bunsho

抄録

Electron–hole recombination in nano-sized titanium(IV) oxide (TiO2) particles with various physical properties, which have been shown to be highly active photocatalysts, was evaluated by quantitative analysis of reduced titanium species (Ti3+), which might be formed at crystalline defective sites in TiO2 particles through photo-irradiation in the presence of a hole scavenger under deaerated conditions. These highly active photocatalyst samples were synthesized by hydrothermal crystallization in organic media (HyCOM method) and post-calcination. The Ti3+ density decreased with increasing calcination temperature (Tc), and a linear correlation was observed between the Ti3+ density and rate constant for electron–hole recombination evaluated by femtosecond pump-probe diffuse reflection spectroscopy. Reaction rate (RAg) and the amount of silver ions (Ag+) adsorbed on TiO2 particles ([Ag+]ads) were measured for photocatalytic silver metal deposition along with oxygen formation from an aqueous Ag+ solution under deaerated conditions, and the slope of the RAg versus [Ag+]ads plot was determined. Kinetic investigation of this reaction showed that the reciprocal of the slope was approximately related to the ratio of the rates for electron–hole recombination and electron trapping (kr/ke ratio). The kr/ke ratio decreased as Tc increased, and the logarithm of the kr/ke ratio was linearly related with Ti3+ density. These two parameters were used as a measure for the recombination properties of TiO2 photocatalysts with various physical properties.

収録刊行物

• Research on Chemical Intermediates

  Research on Chemical Intermediates 33 (3-5), 285-296, 2007

  Springer

キーワード

• electron–hole recombination

詳細情報

• CRID: 1050001339010617216
• NII論文ID: 120003918941
• ISSN: 15685675
• ISSN: 09226168
• HANDLE: 2115/48672
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles