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Abstract In the present work, the surface hydroxyls on rutile TiO2 that evacuated at different temperature were characterized by in suit FTIR The action of OH groups in photocatalytic reaction was tested by adsorption and photooxidation of toluene in an in situ IR cell. The results show that there are seven OH groups(with bands at 3 724, 3 700, 3 652, 3 648, 3 610, 3 413 and 3 362 cm-1) on rutile TiO2 with different thermal stability. Among the seven hydroxyl groups, the OH groups with bands at 3 724, 3 700 and 3 652 cm-1 are thermal stable and are ascribed to isolate hydroxyl groups, while the OH groups with bands at 3 648, 3 610, 3 413 and 3 362 cm-1 are thermal unstable that almost disappear after evacuation at 250 degreesC. During the adsorption of toluene, only the surface hydroxyls with bands 3 648, 3 610 and 3 652 cm-1 act as adsorption sites for adsorption of toluene.

The TiO2 membranes were prepared on glass, ceramic tile and aluminum pieces by Sol-Gel and PVD methods. A fast and exact evaluation on the photocatalytic self-cleaning performance of the membrane materials was achieved by FTIR-ATR technique using oleic acid which was laid on the surface of the membrane. The hydrophilic property of the samples was also determined by the contact angle with water. The results showed that both the TiO2 membrane prepared on glass by the Sol-Gel and PVD methods displayed good photo-induced hydrophilic property and degradation activity of oleic acid, and no difference in hydrophilic property, but the former was a little superior to the latter in photocatalytic activity. The photocatalytic conversion of oleic acid on the TiO2/glass, TiO2/ceramic tile and TiO2 aluminum piece were 92%, 85% and 46%, respectively after illumination 3.5 h, showing a distinct effect of support material property on TiO2 photocatalytic performance. The results suggested that the photocatalytic activity of TiO2 membrane coated on insulator support was higher than that coated on conductor support.

Photocatalytic ceramic was prepared by coating photocatalytic membrane on ceramic matrix. The photocatalytic behavior of the TiO2 coated ceramic for degradation of oleic acid, ethylene, SO2, NOx and sterilization was studied by using XRD, chromatogram, in-situ IR and spectrophotometer. The results showed that the photocatalytic ceramic prepared by special conditions have the function of environmental conservation such as the photodegradating organic contaminants, removing inorganic baleful gas and killing bacteria. Degradation ratio of ethylene, oleic acid, SO2 and NOx reached 95%-100% respectively for the photocatalytic functional ceramic.