Influence of Adsorbed Water and Oxygen on the Photoluminescence and EPR of Por-TiO2 (Anatase)

• Published in: Journal of porous materials Vol. 7; no. 1-3; pp. 389 - 392
• Main Authors: Konstantinova, E, Weidmann, J, Dittrich, Th
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.01.2000
• Subjects: Anatase; Electron paramagnetic resonance; Photoluminescence; Porous materials; Quenching; Radicals; Spectra; Surface chemistry
• ISSN: 1380-2224; 1573-4854
• DOI: 10.1023/A:1009699324013

The influence of adsorbed water, oxygen, air and vacuum on the photoluminescence (PL) and electron paramagnetic resonance (EPR) has been investigated in situ and quasi in situ for por-TiO^sub 2^ (anatase). The broad PL signal in the visible spectral region decreases with increasing partial pressure of oxygen and vanishes at pressures higher than 1 mbar. Adsorption of water leads (i) to a fast quenching and (ii) to a subsequent increase of the PL signal. The concentration of the O^sub 2^^sup -^, O^sup -^, O^sub 3^^sup -^ anion-radicals depends sensitively on the surface conditioning and on the illumination of the por-TiO^sub 2^. Ti^sub 3^+ centers could be observed only in vacuum treated samples. The concentrations of the Ti^sub 3^+ and oxygen anion radicals are in the range of 10^sup 15^ and 10^sup 17^ cm^sup -^3, respectively.[PUBLICATION ABSTRACT]