Influence Of Pt Dispersion On Catalytic Performance Of Ptsncatalyst For Propane Dehydrogenation

Development of catalysts with high activity, selectivity and stability has been the key issue of propane dehydrogenation. In this paper, catalysts with different Pt/Sn ratios and components were prepared by incipient impregnation method. The catalysts were characterized by BET, H2chemi-sorption, NH3-TPD, TPR, XRD, TEM and tested for propane dehydrogenation. The influences of catalyst composition, calcination and reduction conditions on catalyst structural properties, Pt dispersion as well as their catalytic performances were explored. For PtSn/Al2O3catalyts, the addition of tin could enhance the Pt dispersion and the catalytic performances in a certain amount range. The catalyst showed the highest activity when a1:3Pt/Sn molar ratio was adopted at0.5wt%Pt loading. When Pt, Sn and Li were co-impregnated on the support, the loading of Li and interaction between Pt/Sn molar ratio and Li loading were the most prominent factors for the catalytic performances. A suitable calcination temperature was found to be helpful for increasing the Pt dispersion, reducing the strong acid sites amount and therefore the catalytic performances. The optimum calcination temperature was determined to be500℃in the range of this work. The reduction temperature was most important for catalytic performances among all the reduction conditions because the thermo-stability of metal species. An optimum reduction temperature of450℃was obtained in this work. AgPt nanoalloy catalysts with different Pt/Ag ratios were also prepared with chemical reduction method using NaBH4as the reducing agent. Catalytic performances in propane dehydrogenation were studied when AgPt nanoalloy particles were loaded on CNT and Al2O3. The results obtained in this work provided some insight of the structure-activity relationship in propane dehydrogenation on PtSn/Al2O3and maybe helpful for further development of high performance catalysts.