New Adsorbents for Hydrogen Storage and Fuel Desulfurization.

Abstract

Energy and environment have attracted more and more attention in current society. Many efforts have been devoted to developing sustainable solutions to alleviate the potential energy crisis and environmental pollutions. Alternative energy development is one possible approach and hydrogen is considered as a promising and clean alternative energy source in the future. However, its wide applications especially as fuel to power automotives are limited by many factors, one of which is hydrogen storage issue. This thesis discussed about increasing hydrogen storage capacity of adsorbents at ambient conditions by utilizing hydrogen spillover phenomenon and tried to address several challenges related with hydrogen storage. TiF3 was found to be an effective catalyst to facilitate the hydrogen sorption rates on Pt doped carbon, which is also one important criterion for hydrogen application. Through the comparison of hydrogen uptakes on Pt doped IRMOF-8 with different Pt size, it was concluded that smaller metal size and higher dispersion of metal nanoparticles are favorable for hydrogen spillover and thus lead to higher uptakes. The stabilities of MOFs in dihydrogen and dissociated hydrogen environment were also investigated by using XPS, XRD and XAES and it was showed that the reduction potentials of the metal clusters in MOFs play an important role in the stabilities of MOFs, which should be considered as one important factor for future MOF selection for hydrogen storage. The TPD studies demonstrated that the interaction between hydrogen and zeolites (especially the hydrogen chemisorption on zinc exchanged zeolites) was significantly influenced by zinc ion and the zeolite structure, which provided some insights on using zinc exchanged zeolites as the catalysts for H2-SCR. Meanwhile, deep desulfurization attracted much interest due to increasingly stringent environmental regulations on sulfur content as well as possible utilization of liquid fuels for fuel cell applications. Our studies of using adsorbent materials for deep-removing sulfur from transportation fuels were also discussed.