Effect of Support Composition on Catalytic Performance of PtSn/ZSM-5 Catalyst for Propane Dehydrogenation
QIU Anding, LI Enxia, FAN Yining(Key Laboratory of Mesoscopic Chemistry of Education Ministry, Jiangsu Provincial Laboratory for Nanotechnology, College of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, Jiangsu, China)
The effect of ZSM-5 composition on catalytic performance of the supported PtSn/ZSM-5 catalyst for propane dehydrogenation was studied using a microreactor combined with infrared spectroscopy of adsorbed pyridine, temperature-programmed desorption of NH3, thermogravimetry, H2 chemisorption, and temperature-programmed reduction. The results showed that the ZSM-5 composition exerted great influence on the catalytic performance of PtSn/ZSM-5 for propane dehydrogenation. With the increase of SiO2/Al2O3 molar ratio in the ZSM-5 support, the numbers of both total and stronger acidic sites decreased. When the SiO2/Al2O3 molar ratio in the ZSM-5 support increased from 45 to 108, the catalytic activity increased, and the amount of coke formed on the catalyst surface decreased. When the SiO2/Al2O3 molar ratio in the ZSM-5 support was higher than 304, the interaction of Sn species with the ZSM-5 support became weaker, and the ratio of Sn0 species in the catalyst increased after reduction in H2, resulting in the decrease of H2 uptake and catalytic activity of the PtSn/ZSM-5 catalyst for propane dehydrogenation.