Synthesis, Characterization And Applications Of Inorganic Porous Materials

The known reserves of natural gas (mostly methane) are enormous and the reserves are increasing more rapidly than those of liquid petroleum. It is anticipated that this trend will extend well into the 21st century and the effective utilization of methane is becoming more important than ever before. Since the first active catalyst Mo/ZSM-5 was found in 1993, methane non-oxidative aromatization has been a valuable and challengeable research subject in both academy and industry.Moreover, it has been found that materials with both micropores and mesopores can remarkably enhance their activities in the catalytic reactions. Micropores in zeolite provide size and shape-selectivity for guest molecules, while mesopores lead to easier access to the active sites for reactants and better diffuse of the products.In this thesis, a series of intergrowth of zeolite ZSM-11-ZSM-5 were synthesized. Hierarchical porous zeolite of MCM-48-ZSM-5 was also obtained. In addition, mesoporous ZSM-5 were synthesized by addition two styles of carbon into the synthesis gel as meso-template. The mesopores were generated when carbon was burned away. Mo-modified catalysts were prepared and tested for methane dehydro-aromatization reaction. Compared with convensional Mo/H-ZSM-5 catalyst, the intergrowth of Mo/ZSM-11-ZSM-5 catalysts and mesoporous Mo/H-ZSM-5 catalysts showed better catalytic performance. It is considered that the catalytic behavior may be attributed to the generation of secondary mesoporous systems in the crystal, which could improve the accessibility of reactants to the active sites and promote the diffusion of products formed in the microporous channels.