Determining the Structure of Silica-Supported Monomeric Vanadium Oxide Catalysts Based on Synthesis Method and Spectral Data from Theoretical Calculations

Infrared and Raman spectra have been calculated for several molecular cluster models for the silica-supported monomeric vanadium oxide catalysts that are proposed in the literature: the pyramid model, the umbrella model, and a model containing two bonds to the support, a V=O group and an OH group. A related model with one bond to the support, a V=O and two OH groups, will also be discussed. From the comparison with literature, it is concluded that two models, the umbrella model and the model with two bonds to the support, are realistic descriptions of actual systems. The presence of a particular compound depends on the method of preparation. The internal V-O distances by themselves are not enough to distinguish between the presented models.