Creation of Hydrogen-Energy Nano-Spaces

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1) hydrogen-storage nano-materials : Hydrogen storage materials are indispensable for usage of hydrogen energy. Metal nanoparticles, which exhibit different properties from bulk metals, have potential for new functional materials. Since the metal nanoparticles possess large surface area, they are expected to dissociate hydrogen molecules easily and absorb hydrogen at lower temperature and lower pressure. The metal nanoparticles is, therefore, a candidate for a novel hydrogen reservoir. In this study, we prepared the Pd nanoparticle with small size-dispersion and investigated its pressure-composition isotherms and structural change during hydrogen absorption in detail. Mono-dispersed palladium nanoparticles coated with polymer have been prepared and their hydrogen absorption properties were investigated. The averaged diameter of the prepared particles was estimated to be 2.6±0.4nm from a TEM photograph. By measurement of hydrogen pressure-composition isotherms, the hydrogen solubility o … More f the Pd particles was determined to be 0.45 H per Pd. In the isotherms, plateau-like region was observed in the temperature rang of 303 to 393 K, indicating the coexistence of solid solution and hydride phases in the Pd nanoparticles in this temperature region.2) highly proton-conductive coordination polymers : Room-temperature proton conductivity, coordination geometry, and pore-diameter distribution of the title Cu (II) coordination polymer have been investigated by AC conductivity, EXAFS, and N2 adsorption isotherm measurements. The AC proton conductivity (σp) obtained from Cole-Cole plot analysis under relative humidity of 75 % and 300 K exhibits a considerable high value of 10-6 S cm-1 as a room-temperature σp. The mechanism of proton conduction seems to be similar to that of a proton-exchange membrane, Nafion, which contains much cluster of water molecules in the porous space of the polymer. The present Cu coordination polymer was revealed to possess porous space of about 6 A, which includes much water molecules more than 10H20 per unit cell. The dimeric Cu (II) square-planar coordination geometry was confirmed by EXAFS analysis using synchrotron radiation source at SPring-8. Less