Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes

Catalytic reforming accounts for a large share of the world’s gasoline production, it is the most important source of aromatics for the petrochemical industry. In addition, reforming of hydrocarbon on the dual-function catalysts has been found to form fundamentally different products in hydrogen dil...

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Main Authors: A.H. Samia, M.S. Mohammed, S. Faramawy, S.A. Ahmed, H.B. Ahmed
Format: Article
Language:English
Published: Egyptian Petroleum Research Institute 2015-06-01
Series:Egyptian Journal of Petroleum
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Online Access:http://www.sciencedirect.com/science/article/pii/S1110062115000318
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author A.H. Samia
M.S. Mohammed
S. Faramawy
S.A. Ahmed
H.B. Ahmed
author_facet A.H. Samia
M.S. Mohammed
S. Faramawy
S.A. Ahmed
H.B. Ahmed
author_sort A.H. Samia
collection DOAJ
description Catalytic reforming accounts for a large share of the world’s gasoline production, it is the most important source of aromatics for the petrochemical industry. In addition, reforming of hydrocarbon on the dual-function catalysts has been found to form fundamentally different products in hydrogen diluents. Typical catalysts employed for this reforming process are Pt/Al2O3 and Pt-M/Al2O3, M being the promoter. These solids are characterized by both acid and metal functions which catalyze dehydrocyclization, dehydrogenation, isomerization and cracking processes. In this regard, information about cerium and lanthanum, as promoters, is hardly revealed. The present work aims to study the performance of Pt/Al2O3 catalysts modified by lanthanum or cerium during the conversion of cyclohexane, n-hexane and n-heptane. Catalytic activities of the prepared catalysts were tested using a micro catalytic pulse technique. Physicochemical characterization of the solid catalysts such as, surface area (SBET), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hydrogen-temperature programed reduction (H2-TPR), hydrogen-temperature-programed desorption (H2-TPD), CO2-TPD, NH3-TPD, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were depicted. Results indicated clearly that Pt/Al2O3 catalyst is selective toward dehydrogenation to benzene which could be explained as due to the decrease in the active acid sites and the comparative segregation of the alumina support especially at 3% load of CeO. The presence of La2O3 in the Pt/Al2O3 catalyst promotes aromatization of n-hexane and n-heptane, also the dehydrocyclization of n-hexane is more difficult than that of n-heptane. Thus, modification of the Pt/Al2O3 catalyst by La, resulted in a more active and selective reforming catalyst.
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spelling doaj-art-5ee72b7e403c4cb4996fb62dbef1741d2025-08-20T03:04:42ZengEgyptian Petroleum Research InstituteEgyptian Journal of Petroleum1110-06212015-06-0124216317410.1016/j.ejpe.2015.05.007Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanesA.H. Samia0M.S. Mohammed1S. Faramawy2S.A. Ahmed3H.B. Ahmed4Egyptian Petroleum Research Institute, Nasr City 11727, Cairo, EgyptEgyptian Petroleum Research Institute, Nasr City 11727, Cairo, EgyptEgyptian Petroleum Research Institute, Nasr City 11727, Cairo, EgyptEgyptian Petroleum Research Institute, Nasr City 11727, Cairo, EgyptFaculty of Science, AL-Azhar University, Cairo, EgyptCatalytic reforming accounts for a large share of the world’s gasoline production, it is the most important source of aromatics for the petrochemical industry. In addition, reforming of hydrocarbon on the dual-function catalysts has been found to form fundamentally different products in hydrogen diluents. Typical catalysts employed for this reforming process are Pt/Al2O3 and Pt-M/Al2O3, M being the promoter. These solids are characterized by both acid and metal functions which catalyze dehydrocyclization, dehydrogenation, isomerization and cracking processes. In this regard, information about cerium and lanthanum, as promoters, is hardly revealed. The present work aims to study the performance of Pt/Al2O3 catalysts modified by lanthanum or cerium during the conversion of cyclohexane, n-hexane and n-heptane. Catalytic activities of the prepared catalysts were tested using a micro catalytic pulse technique. Physicochemical characterization of the solid catalysts such as, surface area (SBET), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hydrogen-temperature programed reduction (H2-TPR), hydrogen-temperature-programed desorption (H2-TPD), CO2-TPD, NH3-TPD, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were depicted. Results indicated clearly that Pt/Al2O3 catalyst is selective toward dehydrogenation to benzene which could be explained as due to the decrease in the active acid sites and the comparative segregation of the alumina support especially at 3% load of CeO. The presence of La2O3 in the Pt/Al2O3 catalyst promotes aromatization of n-hexane and n-heptane, also the dehydrocyclization of n-hexane is more difficult than that of n-heptane. Thus, modification of the Pt/Al2O3 catalyst by La, resulted in a more active and selective reforming catalyst.http://www.sciencedirect.com/science/article/pii/S1110062115000318DehydrogenationDehydrocyclizationLa, Ce promotionPt/Al2O3Characterization
spellingShingle A.H. Samia
M.S. Mohammed
S. Faramawy
S.A. Ahmed
H.B. Ahmed
Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
Egyptian Journal of Petroleum
Dehydrogenation
Dehydrocyclization
La, Ce promotion
Pt/Al2O3
Characterization
title Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
title_full Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
title_fullStr Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
title_full_unstemmed Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
title_short Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes
title_sort influence of pt nanoparticles modified by la and ce oxides on catalytic dehydrocyclization of n alkanes
topic Dehydrogenation
Dehydrocyclization
La, Ce promotion
Pt/Al2O3
Characterization
url http://www.sciencedirect.com/science/article/pii/S1110062115000318
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