Nanostructured Vanadium Oxide Model Catalysts for Selective Oxidation Reactions

Abstract

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.

Nature of dispersed vanadium oxide: influence of the silica support structure and synthesis methods

“…24 Besides, for monomeric species different structures have been suggested depending on the number of anchoring V-O-Si bonds. 25 As a common structural motif non-monomeric species contain the V-O-V fragment (e.g.…”

“…[18][19][20][21][22][23][24][25] In the following, important aspects of these findings will be briefly discussed. While it is now generally accepted that dehydrated vanadium oxide at low vanadium density (typically at o2 atoms nm…”

Structure of molybdenum oxide supported on silica SBA-15 studied by Raman, UV–Vis and X-ray absorption spectroscopy

“…A grafting/ion-exchange procedure, which has previously been successfully used to prepare SBA-15 supported vanadium oxide catalysts system [32] is applied for the first time to supported molybdenum oxides. As the molybdenum oxide precursor is held electrostatically within the channels of the mesoporous matrix in a prearranged geometry, this method allows one to precisely control the amount and dispersion of the metal oxide introduced into SBA-15 within a broad range of densities.…”

“…As the molybdenum oxide precursor is held electrostatically within the channels of the mesoporous matrix in a prearranged geometry, this method allows one to precisely control the amount and dispersion of the metal oxide introduced into SBA-15 within a broad range of densities. Recently, by such an approach new insight into the structure of silica SBA-15 supported vanadium oxide catalysts has been obtained [32][33][34][35][36].…”

Synthesis and characterization of metastable transition metal oxides and oxide nitrides

“…Possible application areas are, for example, catalysis [14,15], chemical sensors [16], batteries [17], and optical and electric devices [18]. At ambient conditions, vanadium sesquioxide usually crystallizes in the rhombohedral corundum-type structure [19].…”