کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
76974 49153 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of the surfactant on the nanostructure of mesoporous Pt/Mn/WOx/ZrO2 catalysts and their catalytic activity in the hydroisomerization of n-hexane
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Effect of the surfactant on the nanostructure of mesoporous Pt/Mn/WOx/ZrO2 catalysts and their catalytic activity in the hydroisomerization of n-hexane
چکیده انگلیسی

The influence of the cetyl-trimethylammonium bromide (CTAB) as a surfactant over the nanostructure and reactivity of mesoporous Pt/Mn/WOx/ZrO2 materials synthesized by the coprecipitation method and calcined at 800 °C was studied. The Mn/WOx/ZrO2 materials were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), nitrogen adsorption–desorption, and Raman spectroscopy. Their catalytic performance was evaluated on the n-hexane hydroisomerization reaction using the platinum impregnated samples. The results show that the metastable tetragonal zirconia phase was favored by the addition of 1.0 wt.% manganese. The surfactant incorporation in different molar ratios (CTAB/ZrO2) leads to mesoporous solids with higher surface area and narrow pore size distribution. The surface area, pore size and pore size distribution depend on the CTAB/ZrO2 molar ratio. Laser Raman spectroscopy and Rietveld refinement of the crystalline phases confirmed that only a fraction of tungsten (≈5 wt.%) leads to the formation of the WO3 crystalline phase and the reminder is highly dispersed forming amorphous polytungstate species on the zirconia surface. These WOx species are accessible to the n-hexane molecule, leading to an increase in the catalytic activity and selectivity to the biramified products (2,2-DMB and 2,3-DMB).

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microporous and Mesoporous Materials - Volume 89, Issues 1–3, 24 February 2006, Pages 186–195
نویسندگان
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