VOx/SiO2 catalysts were prepared through an innovative flame pyrolysis (FP) technique and tested for the oxidative dehydrogenation of propane. The samples, of different V loadings, were characterized by electron paramagnetic resonance (EPR), micro-Raman, and FT-IR spectroscopy to assess the nature of the vanadium active sites in comparison with a sample prepared by impregnation. The active sites of the FP-prepared catalysts appeared as highly dispersed V5+O groups partly incorporated into the silica matrix and interacting poorly with one another. Lower dispersion can be achieved at the same V loading with the catalyst prepared by impregnation. EPR revealed V4+O groups pointing out normally from the catalyst surface and sitting in the center of a surface array of oxygen atoms. These V4+ groups helped demonstrate the difference in catalytic behavior of the various samples. Catalytic activity measured under both aerobic and anaerobic conditions revealed a promisingly high selectivity with the FP-prepared samples. The best results were obtained with a 10 wt% V loading, which provided the best propylene yield among the samples, especially under anaerobic conditions (up to 80% selectivity at 10% propane conversion). This is likely related to the much higher dispersion of the VOx species in the FP-prepared samples, which also helps reduce the coke formation triggered by exposed surface acid sites.
V2O5-SiO2 systems prepared by flame-pyrolysis as catalysts for the oxidative dehydrogenation of propane / I. Rossetti, L. Fabbrini, N. Ballarini, C. Oliva, F. Cavani, A. Cericola, B. Bonelli, M. Piumetti, E. Garrone, H. Dyrbeck, E.A. Blekkan, L. Forni. - In: JOURNAL OF CATALYSIS. - ISSN 0021-9517. - 256:1(2008), pp. 45-61. [10.1016/j.jcat.2008.02.028]
V2O5-SiO2 systems prepared by flame-pyrolysis as catalysts for the oxidative dehydrogenation of propane
I. RossettiPrimo
;C. Oliva;L. ForniUltimo
2008
Abstract
VOx/SiO2 catalysts were prepared through an innovative flame pyrolysis (FP) technique and tested for the oxidative dehydrogenation of propane. The samples, of different V loadings, were characterized by electron paramagnetic resonance (EPR), micro-Raman, and FT-IR spectroscopy to assess the nature of the vanadium active sites in comparison with a sample prepared by impregnation. The active sites of the FP-prepared catalysts appeared as highly dispersed V5+O groups partly incorporated into the silica matrix and interacting poorly with one another. Lower dispersion can be achieved at the same V loading with the catalyst prepared by impregnation. EPR revealed V4+O groups pointing out normally from the catalyst surface and sitting in the center of a surface array of oxygen atoms. These V4+ groups helped demonstrate the difference in catalytic behavior of the various samples. Catalytic activity measured under both aerobic and anaerobic conditions revealed a promisingly high selectivity with the FP-prepared samples. The best results were obtained with a 10 wt% V loading, which provided the best propylene yield among the samples, especially under anaerobic conditions (up to 80% selectivity at 10% propane conversion). This is likely related to the much higher dispersion of the VOx species in the FP-prepared samples, which also helps reduce the coke formation triggered by exposed surface acid sites.File | Dimensione | Formato | |
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ODH - J Cat 256(2008)45.pdf
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ODH V-Si Revised 25-02-08.pdf
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