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Abstract: 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 non-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.

Keyword: photocatalysis; amorphous nanostructures; composite materials