کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
62718 47652 2008 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
V2O5–SiO2 systems prepared by flame pyrolysis as catalysts for the oxidative dehydrogenation of propane
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
V2O5–SiO2 systems prepared by flame pyrolysis as catalysts for the oxidative dehydrogenation of propane
چکیده انگلیسی

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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 256, Issue 1, 15 May 2008, Pages 45–61
نویسندگان
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