The synthesis and characterization of zeolite and related materials

In this research, SAPO-5 and mesoporous AlPO molecular sieves were synthesized to incorporate Zr(III) into the molecular sieve framework. These materials were characterized by powder X-ray diffraction (PXRD), UV-visible spectroscopy (UV-vis), N2 adsorption isotherms, Scanning Electron Microscopy (SEM), Transmission Electron microscopy (TEM) Thermogravimetric Analysis (TGA), Electron Spin Resonance (ESR), Electron Spin Echo Modulation (ESEM). 31P ESEM was used to identify the location of Zr(III) species generated by gamma-irradiation of ZrAPSO-5 at low Zr/Al ratios. Simulations of the 31P modulation suggest that zirconium substitutes into a phosphorus atom site rather than aluminum atom site.;For mesoporous AlPO materials, AlPO and ZrAlPO were successfully synthesized using tri-block co-polymer as the structure directing agent. The framework contains a non-ideal P/Al ratio less than 1.0 making these materials different from conventional microporous AlPO materials such as AlPO-5 and AlPO-11. The results indicate that the mosopore AlPO consist of three dimensional worms like tubular channels that contain a disordered framework structure but with channel widths that are highly uniform. Thus, the mesoporous materials prepared in the present study exhibit morphologies similar to KIT-1 and MSU-X (where X = 1-4). On evacuation and gamma-irradiation, ESR studies show signals due to Zr3+ in addition to framework defects. The line shape and width of the ESR signals due to Zr3+ indicate that the Zr ions isomorphously substitute for either Al or P.;The growth of single crystals AlPO-5, AlPO-15 and AlPO-21 with high purity has been synthesized by using Al metal as the aluminum source and with different appropriate templates, TEA or TPA, TMA, TMPDA respectively. The influence of synthesis conditions on the crystal size has been studied by systematically changing temperature, the organic template and the gel composition. The products were examined with an optical microscope and by powder X-ray diffraction. Scanning electron microscope images were recorded. Single crystal X-ray diffraction data were measured on a Siemens SMART diffractometer equipped with a CCD area detector using MoKalpha radiation at 293 K. The crystal structure refinements were performed using the program SHELXTL.;Tantalum hydrogen phosphate beta-TaH(PO4)2 has been synthesized by reaction between tantalum oxide and polyphosphoric acid at 380°C. The beta phase has a three dimensional structure that is stable to remarkably high temperature (∼600°C) presumably due to strong hydrogen bonding. Preliminary AC impedance measurements give a conductivity of 2.04 x 10-6 S/cm at 200°C in 5% H2 with an activation energy of 0.56 eV. In further studies aimed at enhancing the conductivity by aliovalent doping, we have investigated systematically the synthesis of compounds in the TaH(PO4)2--W2P2O 11 system at 380°C. As a result of the study, a new phase, Ta 2WO(PO4)4, was identified and, subsequently, the molybdenum analog Ta2MoO(PO4)4 was also prepared.