Work Function of TiO2 (Anatase, Rutile, and Brookite) Single Crystals: Effects of the Environment

0539029 - ÚFCH JH 2022 RIV US eng J - Journal Article
Mansfeldová, Věra - Zlámalová, Magda - Tarábková, Hana - Janda, Pavel - Vorokhta, M. - Piliai, L. - Kavan, Ladislav
Work Function of TiO2 (Anatase, Rutile, and Brookite) Single Crystals: Effects of the Environment.
Journal of Physical Chemistry C. Roč. 125, č. 3 (2021), s. 1902-1912. ISSN 1932-7447. E-ISSN 1932-7455
R&D Projects: GA ČR(CZ) GA18-08959S; GA MŠMT(CZ) LM2018124
Institutional support: RVO:61388955
Keywords : TiO2 * electrochemical impendance spectroscopy * photoelectron spectroscopy
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 4.177, year: 2021
Method of publishing: Limited access

Electrochemical impedance spectroscopy, photoelectron spectroscopy, and Kelvin probe measurements on various TiO2 single-crystal surfaces show that the position of the Fermi level and the conduction band minimum depend significantly on the sample environment (vacuum, air, water vapor, and aqueous or aprotic electrolyte solutions). In most cases, the conduction-band minimum increases in the series: anatase < rutile < brookite. The offset between anatase and rutile indicates a type II staggered alignment if the environment is vacuum, air, water vapor, or aprotic electrolyte solution, but a type IV aligned configuration is found in an aqueous electrolyte solution. The photoelectron spectra in water vapor reveal a strong upshift of the conduction band, which is nearly reversible in the early stages of water/titania interactions. Our results rationalize various earlier contradictions and highlight the need for proper analytical techniques and experimental conditions for investigation of the band energetics, which is relevant to practical applications of titania materials.
Permanent Link: http://hdl.handle.net/11104/0316783