Title:
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Synthesis of tungsten carbide on Al-SBA-15 mesoporous materials by carburization
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Author:
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Alvarez, Mayra G; Chimentao, Ricardo J; Tichit, D.; Santos, Jeannette B O; Dafinov, Antonio; Modesto Lopez, Luis B; Rosell Llompart, Joan; Gueell, E. J.; Gispert Guirado, Francesc; Llorca Piqué, Jordi; Medina Mena, Francisco
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Other authors:
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Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques; Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia |
Abstract:
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Aluminum was incorporated into SBA-15 supports at molar ratios Si/Al = 10 and 2 by the pH-adjusting method. The calcined mesoporous Al-SBA-15 supports, as well as the Al-free SBA-15 support, were impregnated with ammonium paratungstate ((NH4)(10)center dot[H2W12O42]center dot 4H(2)O) aqueous solution. Tungsten carbide (W2C) was synthesized by temperature programmed carburization (TPC) from the. WO3 supported on AI-SBA-15 and SBA-15 in a flow of CH4/H-2. These resultant materials were characterized by powder X-ray diffraction (XRD), N-2 adsorption/desorption, Al-27 NMR and Raman spectroscopies, and transmission electron microscopies (TEM and HRTEM). W2C species were obtained after the carburization process in all the materials. The mesoporous structure of the SBA-15 supports was preserved at all synthesis steps. XRD and TEM analyses revealed that the introduction of aluminum species into the SBA-15 greatly enhanced the dispersion of WO3 and W2C phases during the calcination and carburization steps, respectively. In situ XRD measured during the carburization in a synchrotron facility provided further details of the reduction of tungsten trioxide species as a function of temperature. The presence of aluminum in the SBA-15 notably affected the distribution and the reduction temperature of the tungsten oxide species. (C) 2015 Elsevier Inc. All rights reserved. |
Subject(s):
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-Àrees temàtiques de la UPC::Enginyeria dels materials -Àrees temàtiques de la UPC::Enginyeria química::Indústries químiques -X-rays - Diffraction -Aluminum -Tungsten carbide -Mesoporous silica -SBA-15 -Al-SBA-15 -Natural-gas lng -Hydrogen-production -Raman-spectroscopy -Catalysts -Silica -Molybdenum -Crystal -Alumina -Raigs X--Difracció -Alumini |
Rights:
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http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
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Article - Submitted version Article |
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