Amorphous composite photocatalysts: a new generation of active materials for environment application

Currently, only the semiconductors (usually in the form of nanometric; particles) are considered to be efficient photocatalysts. The most wide-spread photocatalytic agent is Degussa P25. Unfortunately, this prefabricated crystalline species is not specially adapted for application because of the well-known handling problems. At present, any now. crystalline material is really recognized to be an active photocatalyst. This work attempts to highlight the photocatalytic properties of non-crystalline composite materials containing nanosized amorphous TiO2 chemically fixed on different mineral supports. For comparative tests, a series of composite photocatalysts containing crystalline TiO2 nano-aggregates was also fabricated. In both cases, the elaboration technique was based on the principles of the Chemical Vapor Deposition - Molecular Layering (CVD-ML) method. The non-crystalline TiO2 nano-composites manifest both significant photocatalytic activities exceeding that of Degussa P25 (test reactions - trichloroethane and toluene oxidation in gaseous phase) and important sterilization capacities under UV-A and sunlight irradiation.