کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
43873 45993 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of Mo2C–WO2 composite catalysts for bifunctional isomerization: A new pulse method to quantify acid sites
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Characterization of Mo2C–WO2 composite catalysts for bifunctional isomerization: A new pulse method to quantify acid sites
چکیده انگلیسی

New bimetallic catalysts containing molybdenum carbide (Mo2C) and tungsten dioxide (WO2) with three different Mo/W ratios were synthesized by temperature programmed reaction in flow of C2H6/H2 mixture and used for the bifunctional isomerization of n-heptane. They are characterized by X-ray diffraction (XRD), electron diffraction (ED), transmission electron spectroscopy (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), N2 sorption, CO chemisorption and adsorption–desorption of iso-propylamine. New pulse method based on the adsorption–desorption of iso-propylamine was used to estimate the total amount of acid sites of which are differentiated the number of Lewis and Brönsted acid sites. XPS shows that only molybdenum and a limited part of tungsten are reduced while the major part of tungsten is under oxide form as WO2. The adsorption of CO allows estimating the number of metallic sites (Mo2C) and coke is formed during the isomerization of n-heptane on Brönsted acid sites (WO2). A kinetic study gives that the reaction order is first for n-heptane conversion. The stabilisation of activity and high selectivity to iso-C7 from 86 to 94% for the isomerization of n-heptane are observed after induction period of 9 h. The turnover rate (TOR) is 0.1 s−1 at 300 °C.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 302, Issue 1, 21 March 2006, Pages 5–13
نویسندگان
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