Mesoporous silica–alumina as support for Pt and Pt–Mo sulfide catalysts: Effect of Pt loading on activity and selectivity in HDS and HDN of model compounds

The potential of mesoporous silica–alumina (MSA) material as support for the preparation of sulfided Pt and Pt–Mo catalysts of varying Pt loadings was studied. The catalysts were characterized by their texture, hydrogen adsorption, transmission electron microscopy, temperature programmed reduction (...

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Bibliographic Details
Published in:Applied catalysis. B, Environmental Environmental, 2009-04, Vol.87 (3-4), p.171-180
Main Authors: Gulková, Daniela, Yoshimura, Yuji, Vít, Zdeněk
Format: Article
Language:English
Subjects:
Adsorption
Catalysis
Catalysts
Chemistry
Colloidal state and disperse state
Exact sciences and technology
General and physical chemistry
Hydrodenitrogenation
Hydrodesulfurization
Hydrogen
Microscopy
Molybdenum sulfide catalyst
MSA
Platinum
Porous materials
pyridines
Q1
Sulfides
Sulfur
Surface physical chemistry
Temperature
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
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Summary:The potential of mesoporous silica–alumina (MSA) material as support for the preparation of sulfided Pt and Pt–Mo catalysts of varying Pt loadings was studied. The catalysts were characterized by their texture, hydrogen adsorption, transmission electron microscopy, temperature programmed reduction (TPR) and by activity in simultaneous hydrodesulfurization (HDS) of thiophene and hydrodenitrogenation (HDN) of pyridine. Sulfided Pt/MSA catalysts with 1.3 and 2wt.% Pt showed almost the same HDS and higher HDN activities per weight amounts as conventional CoMo and NiMo/Al2O3, respectively. The addition of Pt to sulfided Mo/MSA led to promotion in HDS and HDN with an optimal promoter content close to 0.5wt.%. The results of TPR showed strong positive effect of Pt on reducibility of the MoS2 phase which obviously reflects in higher activity of the promoted catalysts. The activity of the MSA-supported Pt–Mo catalyst containing 0.5wt.% Pt was significantly higher than the activity of alumina-supported Pt–Mo catalyst. Generally, Pt–Mo/MSA catalysts promoted by 0.3–2.3wt.% Pt showed lower HDS and much higher HDN activities as compared to weight amounts of CoMo and NiMo/Al2O3. It is proposed that thiophene HDS and pyridine hydrogenation proceed over Pt/MSA and the majority of Pt–Mo/MSA catalysts on the same type of catalytic sites, which are associated with sulfided Pt and MoS2 phases. On the contrary, piperidine hydrogenolysis takes place on different sites, most likely on metallic Pt fraction or sites created by abstraction of sulfur from MoS2 in the presence of Pt.
ISSN:0926-3373
1873-3883
DOI:10.1016/j.apcatb.2008.09.004