The Structure And Catalytic Properties Of Supported PtSnNa/SUZ-4 Catalysts For Propane Dehydrogenation

Propane dehydrogenation to propene is one of the most important processes of petroleum chemical industries. In this work, the structure and catalytic properties of supported PtSnNa/SUZ-4 catalysts for propane dehydrogenation have been studied by using X-ray diffraction (XRD), H2 chemisorption, NH3 temperature-programmed desorption (NH3-TPD), temperature-programmed oxidation (TPO) and H2 temperature-programmed reduction (H2-TPR) combined with microreator tests. It has been shown that the propene selectivity and catalytic stability of supported PtSnNa/SUZ-4 catalyst is higher than those of supported PtSnNa/ZSM-5 catalyst with same composition. This is because of not only Pt dispersion in external surface of SUZ-4 support and less coverage of Pt by coke formed in the reaction of propane dehydrogenation but aslo the stronger interaction of Sn with SUZ-4 support and the Sn component is more difficult to be reduced. The Na+ component in the supported PtSnNa/SUZ-4 catalysts can neutralize the strong acidic sites on the surface of SUZ-4 zeolite support, increasing the Pt dispersion and suppressing the cracking of olefin products and the formation of coke, leading to the increases of propene selectivity and catalytic stability. But, excessive Na+ ions in the catalyst decreases the interaction between Sn component and SUZ-4 zeolite support, resulting in the drastic decrease of catalytic activity for propane dehydrogenation.