Synthesis Of Hydrothermally Stable Materials With Hierarchical Pores Via In-Situ Assembly Of Zeolite Y Precursors

It has been widely recognized that the creation of mesopores and macropores and construction of hierarchical pores are an effective way to improve the accessibility of the active centers.Moreover,hard templates such as carbon black and PS microspheres are generally employed to assemble ordered macropores.By optimizing the synthesis of zeolite Y precursors,a novel method for fabricating hierarchically macro-meso-microporous materials and a facile strategy to finely manipulate the microporosity of meso-microporous materials were developed.In this thesis,a series of hydrothermally stable composites with graded pores were synthesized via in-situ assembly of zeolite Y precursors by P123/carbon black templates.Various methods such as XRD,FT-IR,TEM,BET and NH₃-TPD are used to characterize the materals.The results of FT-IR showed that the primary and secondary structural building units of zeolite Y were introduced into the walls of zeolites.The results of BET and TEM suggested that the composites had interconnected hierarchical graded pores structure(0.39 nm-3.8 nm-6.5 nm-19.9 nm).The surface area and pore volume were 693 m²Â·g^-1and 1.89 ml·g^-1respectively.After hydrothermal treatment at 100%vapor,800℃for 2 h and 4 h,the remaining fractions of surface area were 80.1%and 35.1%respectively,while the remaining fractions of pore volume were 45.0%and 25.4%respectively.The present thesis provide a novel route for fabricating materials with hierarchical pores and high hydrothermal stability which are candidates for heavy oil cracking catalysts.