THE INFLUENCE OF COMMERCIAL TIO2 MODIFICATIONS ON THE CATALYTIC PROPERTIES OF V2O5/TIO2 CATALYSTS

The known promotion effect of anatase on the catalytic activity of V2O5 in V2O5/TiO2 catalysts is caused by the presence of alkali metal ions of commercial anatase pigments. The content of alkali metal ions permits by a suitable V2O5/TiO2 ratio the formation of different phases of an alkali metal-V-O-bronze. The a phase is characterized by a greater reversible degree of reduction than the beta-phase of alkali metal-V-O-bronze and the pure V2O5 resp. The cause for such a behaviour is, that the a phase of alkali metal-V-O-bronze during the redox processes pass over only into the favourable reoxidable V2O4(B)phase.