Electronic states and photoexcitation processes of titanium dioxide nanoparticle films dip coated from aqueous Degussa P25 photocatalyst suspension
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016 (New Zealand)
The electronic properties of titanium dioxide (TiO{sub 2}) nanocrystalline films, which were prepared by dip coating from Degussa P25 photocatalyst aqueous suspension, have been investigated by surface photovoltage spectroscopy (SPS). As indicated by the positive contact potential difference (CPD) change in the sub-band-gap region, SPS shows that the molecularly adsorbed H{sub 2}O in the freshly prepared P25 film creates an empty electron state, which is distributed within 0.79 eV below the conduction band edge, and acts as an electron trap and carrier recombination center. With film aging or under a drying atmosphere, the H{sub 2}O-associated state diminishes, and the occupied electron state due to molecularly adsorbed oxygen, lying within 1.06 eV above the valence band edge, is identified by the reversed polarity of the CPD change in the sub-band-gap region. This information is important in developing a better understanding of real photocatalyst behavior.
- OSTI ID:
- 20982640
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 101; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Explaining the enhanced photocatalytic activity of Degussa P25 mixed phase TiO{sub 2} using EPR.
Effect of isopropyl alcohol on the surface localization and recombination of conduction-band electrons in Degussa P25 TiO sub 2. A pulse-radiolysis time-resolved microwave conductivity study. [Accelerated electrons]