INOR 251 |
| Mesoporous and microporous titanium oxides were reduced and/or impregnated by a variety of reducing agents, such as alkali metals, organometallic sandwich compounds of Ti, V, and Cr, as well as alkali fullerides. The hydrogen sorption properties were investigated for these new composite materials at 77 K. Surprisingly, the reduction in the surface Ti species had a greater effect on the storage densities than surface area or pore size. For example, the microporous Ti material reduced with bis(toluene) Ti possesses a surface area of 208 m2/g, but exhibits an overall volumetric storage capacity of 40.46 kg/m3 at 77K and 100 atm. This volumetric storage capacity is higher than that of pristine material, which has a surface area of 942 m2/g. Another surprising feature in these reduced materials is the unusual trend in enthalpies, which show an unprecedented increase in binding strength as the surface coverage increase. The binding enthalpies also increase on progressive reduction, demonstrating that precise tuning of the enthalpies and even higher storage capacities may be possible by choosing the right reducing agent. These features suggest a Kubas-type interaction for hydrogen binding in some of these materials. |
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Nanoscience: Applications
7:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Sci-Mix
Division of Inorganic Chemistry |