This work focuses on the synthesis and photocatalytic performance of mesoporous TiO 2 films containing embedded gold nanostructures. The TiO 2 films were prepared by the EISA (evaporation-induced selfassembly) process and loaded with Au either by impregnation followed by reduction with NaBH 4 or by pulsed cathodic electrodeposition. The latter approach represents a considerably easier and faster synthetic method and results in dendritic Au nanostructures as a replica of the pore system. The as-prepared composite films were characterized by scanning and transmission electron microscopy (SEM and TEM), UV-vis spectroscopy and Kr adsorption. Photocatalytic oxidation of NO was chosen as the test reaction for elimination of air pollutants. For mesoporous TiO 2 films deposited on an ITO layer, the photonic efficiency is higher than for films prepared on glass, because the pore structures are altered. Incorporation of Au results in a significant improvement in the photonic efficiency due to the generation of Schottky barriers, which inhibit the recombination of electron-hole pairs and thereby increase the concentration of photogenerated holes at the film surface reacting with NO. Compared to the impregnated nanocomposites, mesoporous TiO 2 films with electrochemically incorporated dendritic Au nanostructures provide comparable photocatalytic activities, but their preparation is much less time-consuming and of lower cost. An additional treatment with O 2 plasma leads to further increase in the photocatalytic activity due to the higher amount of hydroxyl groups on the surface, which play a significant role in the photocatalytic oxidation of NO. Mesoporous nanocomposite films are promising in photocatalysis and self-cleaning technologies.

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TiO 2 /benzoquinone hybrid films have been electrodeposited anodically from basic Ti(IV)-alkoxide solutions containing hydroquinone. The films were calcined at different temperatures between 350 and 550 °C and investigated in view of applications as photocatalyst and in dye-sensitized solar cells. Thermogravimetry analysis, differential thermo analysis, in situ X-ray diffraction, and transmission electron microscopy show the removal of the benzoquinone and starting crystallization of the TiO 2 between 350 and 400 °C, followed by a further increase in the crystallinity and particle size with increasing calcination temperature, while the specific surface area is decreased due to an increasing pore size as confirmed by Kr adsorption measurements. In dye-sensitized solar cells, the higher crystallinity leads to an improved performance mainly due to improved adsorption of sensitizer dyes up to calcination temperatures of 500 °C, while all films exhibit good electron collection properties as investigated by intensity-modulated photoelectrochemical techniques. The latter can be explained by the presence of conducting pathways provided by the benzoquinone for films calcined at lower temperature and by the presence of crystalline TiO 2 for films calcined at higher temperatures. A further increase of the calcination temperature to 550 °C leads to a decrease in efficiency due to a further decrease in the surface area. In contrast, the highest photocatalytic activity was found for a calcination temperature of 550 °C, indicating the importance of having highly crystalline and pure materials for photocatalytic applications.

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Crystalline TiO

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