In order to study the correlation between the mass transfer performance of fluid catalytic cracking (FCC) catalysts and their pore structure and acidity,three semi synthetic FCC catalyst samples(CAT1,CAT2,CAT3) with different pore structure and acidity were prepared.Naphthalene,phenanthrene and acridine were selected as probe molecules to test the adsorption penetration performance of the guest molecules on the catalysts and to investigate their mass transfer performance.The ability of acid center conversion on catalysts was visualized and analyzed using super-resolution imaging technology.The results show that effective discrimination of the differential adsorption behavior of FCC catalysts for macromolecules can be achieved by selecting suitable probe molecules.The mass transfer performance of macromolecules on FCC catalysts depends on the pore structure and surface acidity of the catalysts.The use of novel macroporous matrix materials optimizes the mass transfer performance of FCC catalysts and enhances the acid on Y molecular sieves in FCC catalysts centers in FCC catalysts.The work can provide an effective solution for studying the mass transfer structure-activity relationship of FCC catalysts,and also provide theoretical guidance for the design of efficient FCC catalysts.

The properties of alumina supports are the key factors affecting the propane dehydrogenation performance of Pt?Sn/γ?Al₂O₃ catalysts.In this paper,γ?Al₂O₃ supports were prepared at three calcination temperatures of 450,650,850 ℃,and the structures and properties of the supports and supported catalysts were systematically studied by XRD,XRF,NH₃?TPD,Py?FTIR, CO?FTIR,OH?FTIR,and other characterization methods.The properties of the propane dehydrogenation reaction were evaluated by a fixed?bed micro?reaction evaluation device with online analysis,and the gas?phase product distribution and coking properties were analyzed.The results show that with the increase in calcination temperature,the surface acid content of γ?Al₂O₃ supports decreases,and calcination at 850 ℃ almost eliminates the weak L acid centers on the surface.This indicates that the number of coordinated unsaturated Al sites on the surface of γ?Al₂O₃ and surface hydroxyl groups decreases as the calcination temperature grows,which is not conducive to the high dispersion of metal active centers.Both CO?FTIR and TEM results confirm the formation of larger Pt clusters on Pt?Sn/γ?Al₂O₃?850,and more Pt active phase structure with saturated coordination can promote the occurrence of side reactions such as deep dehydrogenation and reduce the selectivity of propylene products.