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Free keywords:
propane adsorption; silica supported vanadium oxide catalysts; microcalorimetry; FTIR spectroscopy
SFB: V-oxides: clusters and catalysts; preparation & internal structure
Abstract:
A series of SBA-15 supported VxOy catalysts was prepared and characterized by N2 adsorption and Raman, UVvis, and XP spectroscopies. The surface sites were probed by propane adsorption after various treatments. IR spectra indicate several types of OH groups, some of which are dehydroxylated at increasing temperature, leading to a stronger interaction of the remaining OH groups with propane. These results are corroborated by the heats of adsorption of propane, which reach 60, 80, and 170 kJ/mol after activation at 373, 573, and 673 K. The surface can be rehydroxylated, and it is proposed that the steam necessary for the conversion of propane to acrylic acid also adjusts the surface acidity.
