Surface Photodeposition of Metal Oxides by Decomposition of Several Group IVAOrganometallics (benzyltrimethylsilanes and benzyltrimethylstannanes) on TiO2

摘要

The photocatalytic decomposition of several substituted benzyltrimethylsilanesand benzyltrimethylstannanes on band gap irradiated TiO(2) powders suspended in acetonitrile causes the deposition of SiR(x) and SiO(2) and of SnR(x) and SnO(2) respectively, on the photoactive surface. A mechanism consistent with interfacial trapping of a photogenerated electron-hole pair can successfully rationalize the observed kinetics and substituent effects. The absorption of light by a titanium dioxide particle activates it for two contrasting applications: as a photocatalyst or as an inert, reflective white pigment. The photocatalytic activity of n-TiO(2) powder is of interest as a means for solar energy conversion for the synthesis of useful chemicals and for the conversion of toxic compounds to innocuous or less harmful forms. This same activity, however, is troublesome to paint chemists whose objective is to prolong the lifetime of polymers coating the TiO(2) particles and, thus to minimize polymer chain cleaving photoactivity.