The catalytic activities and properties of platinum supported on siliceous MCM-41 and Al-modified MCM-41, such as Al-incorporated MCM-41 (AlMCM-41) and alumina-modified MCM-41 (Al_2O_3-MCM-41), for the hydrodesulfurization (HDS) of thiophene were investigated. Al_2O_3-MCM-41 was prepared by an impregnation method using aluminum nitrate (Al(NO_3)_3·9H_2O) aqueous solution. Pt/Al_2O_3-MCM-41 catalyst showed high and stable activity for HDS of thiophene and this activity was remarkably higher than that of a commercial CoMo/Al_2O_3 HDS catalyst. The catalysts were characterized by XRD, hydrogen adsorption, ammonia-TPD, 2-propanol dehydration, cumene cracking and FT-IR. Dispersion of platinum on Al_2O_3-MCM-41 was remarkably higher than on MCM-41 or on AlMCM-41. It was revealed that the acidity of Al_2O_3-MCM-41 was higher than that of MCM-41 or of AlMCM-41. Furthermore, it was observed that there exist Brønsted acid sites on Al-modified MCM-41. FT-IR spectra of thiophene adsorbed on Al-modified MCM-41 support indicates that thiophene molecules interact with Brønsted acid sites on Al-modified MCM-41. It was found that the HDS activity of Pt/quartz mixed mechanically with Al-modified MCM-41 catalyst was higher than that calculated. This suggests that there exists spillover hydrogen on supportedPt catalysts in the HDS of thiophene. Results revealed that the high activity of Pt/Al_2O_3-MCM-41 catalyst for HDS reaction is due to good harmony of high dispersion of Pt particles and Brønsted acidity of the support.
Effect of aluminum modification on catalytic performance of Pt supported on MCM-41 for thiophene hydrodesulfurization
Appl.Catal.A308_111_2006.pdf
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