Experimental and Molecular Simulation Studies of a ZSM-5-MCM-41 Micro-mesoporous Molecular sieve

摘要

Micro-mesoporous molecular sieves are novel porous materials which are equipped with long-range parallel mesopore channels like periodic mesoporous silica (PMS) materials, and its adjacent mesopores are connected to each other through micropore walls of zeolites. Such materials can be used as highly functional adsorbents, catalyst supports and nanoreactors, because micropores and mesopores play a cooperative role as gas or fluid paths and molecular adsorption sites or reserviors. Furthermore, the introduction of the zeolite structure provided micro-mesoporous molecular sieves significantly more acidity sites than those of PMS. In this paper, ZSM-5-MCM-41 micro-mesoporous composites are synthesized by a two-step crystallization process based on the polymerization of ZSM-5 nanocluster precursors confined to the MCM-41 structure-directing agent, and microwave radiation crystallization technology is chosen in synthesis process. In addition, the structure model of ZSM-5-MCM-41 is built by using molecular modeling technique, and then characterized by calculating the accessible solvent surface area, total pore volume, small-angle and wide-angle X-ray diffraction patterns, and toluene adsorption using Materials Studio. The calculated results are proved and compared with corresponding experiment results, such as N2 adsorption-desorption isotherms, X-ray power diffraction patterns, and toluene adsorption.