Sensitization of titanium dioxide in the visible light region using zinc porphyrins

Abstract

of ruthenium atoms in a site. If there is preferential interaction of copper with the defects, as can be inferred from the results of the present work, it would be reasonable for copper to have a different effect on the catalytic activity of ruthenium when defects are present. Consequently, the effect of copper on catalytic activity could well be different for a ruthenium powder than it is for a smooth (001) plane of ruthenium.The results of the present investigation clearly demonstrate the value of ultraviolet photoemission spectroscopy of physisorbed xenon as a probe of surfaces of interest in catalysis. Since it is sensitive to localized properties of the surface, it is a powerful probe for the detection of surface heterogeneity. It can therefore make a useful contribution in studies of the structure sensitivity of surface-catalyzed reactions.

Photosensitization of a colloidal TiO2 semiconductor system with hypocrellin B

“…The transparent dispension of colloidal TiO 2 was prepared by hydrolysis of TiCl 4 at 0 C [10][11][12]. The stock dispersion was 6.00Â10 À3 mol/l in colloidal TiO 2 stabilized by poly(vinyl alcohol; PVA, 0.1%).…”

“…2). The decrease in the fluorescence emission could be attributed to interfacial electron transfer, the concentration quenching among the adsorbed sensitizer molecules [11] or energy transfer between the sensitizer and the colloidal TiO 2 . The bandgap energy of TiO 2 semiconductor is greater than that of the sensitizer, (it can be deduced from the position of their absorption bands in Fig.…”

Parameters Influencing Charge Recombination Kinetics in Dye-Sensitized Nanocrystalline Titanium Dioxide Films

“…In contrast, the corresponding charge recombination reaction between injected electrons and dye cations has been reported to exhibit time constants ranging from picoseconds to milliseconds. [12][13][14][15][16][17][18][19][20][21] Previous studies have considered a range of different sensitizer dyes, semiconductor materials, and electrolyte compositions. However, agreement over the parameters underlying the large variation in experimental time constants has been limited to date.…”

Electron transfer in colloidal TiO2 semiconductors sensitized by hypocrellin A

“…Time-resolved laser flash photolysis is very useful in the investigation of the interfacial electron-transfer processes in colloidal semiconductor system (Moser and Graetzal, 1984;Kamat et al, 1986;Kalyanasundaram et al, 1987). If electron injection from the excited state of HA to the conduction band of the semiconductor occurred, the radical cation HA d+ should be detected.…”