HYDROGEN STORAGE VIA CATALTICALLY ENHANCED METAL HYDRIDES

The dehydrogenation kinetics of NaAlH4 re significantly enhanced upon doping with zirconium through homogenization with 2 mole % Zr(OPr)4. TPD measurements show that zirconium is inferior to titanium as a catalyst for the dehydriding of NaAlH4 to Na3AlH6 and Al but a superior catalyst for the dehydriding of Na3AlH6 to aH and Al. The benefit of both catalytic effects can be realized in materials containing a combination of both titanium and zirconium catalysts. After the initial dehydriding/rehydriding cycle, NaAlH4 which is doped with titanium and/or zirconium are stabilized with a greater than 4 wt % cyclable hydrogen capacity. The unset of rapid dehydriding occurs in the titanium containing materials at temperatures below 100 ˚C. A 100 g sample of the Ti/Zr doped NaAlH4 has been successfully prepared and loaded into modular test beds at SNL