Controlled synthesis based on spectroscopic characterization, structure, and catalytic performance of mesoporous silica SBA-15-supported vanadium oxide model catalysts (see TEM image) are reviewed. The effect of water on the structure and dispersion of highly dispersed vanadium oxide is discussed in the light of recent results in multiple in situ spectroscopy.Characterization of the synthesis, structure, and catalytic performance of vanadium oxide catalysts supported on mesoporous silica SBA-15 for selective oxidation reactions are reviewed. Controlled synthesis on the basis of surface functionalization and ion exchange allows homogeneous deposition of vanadium oxide within the pores of SBA-15. Catalytic tests on the selective oxidation of methanol and propane demonstrate the full catalytic function of these model powder catalysts. Characterization of the dehydrated state by vibrational spectroscopy provides insight into the structure of SBA-15-supported vanadium oxide at low loadings. The effect of water on the structure and dispersion of highly dispersed vanadium oxide is discussed in light of recent results from multiple in situ spectroscopy.