Abstract
Mesoporous VO x /SBA-15 samples have been prepared by different impregnation methods, characterized by N2 adsorption and diffuse reflectance UV–visible spectroscopy, and their photocatalytic reactivity evaluated for the selective oxidation of methane with oxygen at 220 °C under UV irradiation. Vanadium in dehydrated VO x /SBA-15 samples was found to be predominantly as isolated four-coordinated V5+ species, especially at V loading below 2.5 wt%. VO x /SBA-15 catalysts prepared by impregnation with an aqueous solution of ammonium metavanadate (AMV) showed a maximum rate of formation of formaldehyde of 525 μmol g-1 h-1 (selectivity of 93.8 mol%) at a vanadium content of 2.65 wt%. Both the rate of formation and selectivity of formaldehyde were improved when vanadium was impregnated on the SBA-15 support from a vanadyl sulfate methanolic solution (rate of formation of HCHO = 733 μmol g-1 h-1, selectivity = 95.4 mol%). VO x /SBA-15 catalysts were seen to be more effective for the selective photo-assisted oxidation of methane than VO x /SiO2 catalysts.
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López, H.H., Martínez, A. Selective Photo-Assisted Oxidation of Methane into Formaldehyde on Mesoporous VO x /SBA-15 Catalysts. Catalysis Letters 83, 37–41 (2002). https://doi.org/10.1023/A:1020649313699
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DOI: https://doi.org/10.1023/A:1020649313699