Photoelectrochemistry and interfacial energetics of titanium dioxide photoelectrodes in fluoride-containing solutions

Journal Article · Thu Jan 11 00:00:00 EST 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100364a071· OSTI ID:6732817

Wang, Chong Mou; Mallouk, T E ^[1]

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1. Univ. of Texas, Austin (USA)

Current-potential and ac impedance measurements were used to characterize the semiconductor/solution interface for TiO{sub 2-x} and TiO{sub 2-x}F{sub x} single-crystal electrodes in anhydrous HF/NaF and acetonitrile/tetraethylammonium fluoride (TEAF) solutions. In HF/NaF, photoelectrochemical evolution of elemental fluorine occurs at potentials positive of the flatband potential, E{sub fb}, which is +0.6 V vs the H{sup +}/H{sub 2} formal potential. Photocorrosion occurs readily in this medium with TiO{sub 2-x} but not with TiO{sub 2-x}F{sub x}. No photocurrent is observed even at very positive potentials in acetonitrile/TEAF, and Mott-Schottky plots show that E{sub fb} is {minus}2.10 V vs NHE in this medium and that the valence band-edge potential is therefore negative of the F{sup {minus}}/F{sub 2} formal potential. The ideal photoelectrochemical behavior and low photocorrosion rate observed with TiO{sub 2-x}F{sub x} are attributed to a low density of interband surface states ((3-7) {times} 10{sup 11} cm{sup {minus}2}), tentatively assigned to Ti{sup 3+} deep levels. No oxygen vacancy states are detected at the TiO{sub 2-x}F{sub x} surface, in either HG/NaF or acetonitrile/TEAF, by the ac impedance technique.

• OSTI ID: 6732817
• Journal Information: Journal of Physical Chemistry; (USA), Vol. 94:1; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
TITANIUM OXIDES
ELECTROCHEMISTRY
PHOTOCHEMISTRY
DATA ANALYSIS
EXPERIMENTAL DATA
IMPEDANCE
INTERFACES
MEASURING INSTRUMENTS
MEASURING METHODS
PHOTOANODES
PHOTOCATHODES
SEMICONDUCTOR MATERIALS
ANODES
CATHODES
CHALCOGENIDES
CHEMISTRY
DATA
ELECTRODES
INFORMATION
MATERIALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties
400500 - Photochemistry
400400 - Electrochemistry