Abstract
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 (T c), 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 (R Ag) 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 R Ag 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 (k r/k e ratio). The k r/k e ratio decreased as T c increased, and the logarithm of the k r/k e 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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
D. P. Colombo, Jr., and R. M. Bowman, J. Phys. Chem. 99, 11752 (1995).
B. Ohtani, R. M. Bowman, D. P. Colombo Jr., H. Kominami, H. Noguchi and K. Uosaki, Chem. Lett. 579 (1998).
A. Furube, T. Asahi, H. Masuhara, H. Yamashita and M. Anpo, J. Phys. Chem. 103, 3120 (1999).
S. Ikeda, N. Sugiyama, B. Pal, G. Marci, L. Palmisano, H. Noguchi, K. Uosaki and B. Ohtani, Phys. Chem. Chem. Phys. 3, 267 (2001).
S. Ikeda, N. Sugiyama, S.-Y. Murakami, H. Kominami, K. Kera, H. Noguchi, K. Uosaki, T. Torimoto and B. Ohtani, Phys. Chem. Chem. Phys. 5, 778 (2003).
H. Kominami, Y. Takada, H. Yamagiwa, Y. Kera, M. Inoue and T. Inui, J. Mater. Sci. Lett. 15, 197 (1996).
H. Kominami, M. Kohno, Y. Takada, M. Inoue, T. Inui and Y. Kera, Ind. Eng. Chem. Res. 38, 3925 (1999).
H. Kominami, S.-Y. Murakami, Y. Kera and B. Ohtani, Catal. Lett. 56, 125 (1998).
T. Watanabe and K. Honda, J. Phys. Chem. 86, 2617 (1982).
B. Ohtani, Y. Okugawa, S.-I. Nishimoto and T. Kagiya, J. Phys. Chem. 91, 3350 (1987).
B. Ohtani, M. Kakimoto, S.-I. Nishimoto and T. Kagiya, J. Phys. Chem. 92, 5773 (1988).
H. Kominami, S.-Y. Murakami, J.-I. Kato, Y. Kera and B. Ohtani, J. Phys. Chem. B 106, 10501 (2002).
H. Kominami, S.-Y. Murakami, M. Kohno, Y. Kera, K. Okada and B. Ohtani, Phys. Chem. Chem. Phys. 3, 4102 (2001).
H. Kominami, K.-I. Yabutani, T. Yamamoto, Y. Kera and B. Ohtani, J. Mater. Chem. 11, 3222 (2001).
Y. Osawa and M. Graetzel, J. Chem. Soc. Faraday Trans. l 84, 197 (1988).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Murakami, SY., Kominami, H., Kera, Y. et al. Evaluation of electron-hole recombination properties of titanium (IV) oxide particles with high photocatalytic activity. Res. Chem. Intermed. 33, 285–296 (2007). https://doi.org/10.1163/156856707779238612
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1163/156856707779238612