Ti-doped alkali metal aluminium hydrides as potential novel reversible hydrogen storage materials

Metal-doped sodium aluminium hydrides as potential new hydrogen storage materials

A vibrating-mill technique, which can activate the reaction system by bringing the reagents into very close contact at the preparative scale and by providing extra mechanical energy, much more effectively than the well-known ball-milling method, was used to prepare titanium(III) chloride (TiCl3·1/3AlCl3)-doped lithium tetrahydridoaluminate (LiAlH4) and lithium hexahydridoaluminate (Li3AlH6) powders with nanocrystallites. The phase structure and dehydriding/rehydriding properties were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), and differential scanning calorimetry (DSC). The mechanism of reversible dehydrogenation and rehydrogenation was examined by means of X-ray photoelectron spectroscopy (XPS). Thermodynamic and kinetic measurements showed a distinct change for the dehydriding/rehydriding reactions over the temperature range 25−250 °C. From the Arrhenius plot of hydrogen desorption kinetics, apparent activation energies were found to be 42....

Reversible Hydrogen Storage via Titanium-Catalyzed LiAlH4 and Li3AlH6

The mechanism of the hydrogen desorption (HD) reaction from the 1:1 mixture of lithium amide (LiNH2) and lithium hydride (LiH) to lithium imide (Li2NH) and hydrogen (H2) has been proposed on the ba...

Mechanism of Novel Reaction from LiNH2 and LiH to Li2NH and H2 as a Promising Hydrogen Storage System

The gas-phase loading of [Zn(4)O(btb)(2)](8) (MOF-177; H(3)btb=1,3,5-benzenetribenzoic acid) with the volatile platinum precursor [Me(3)PtCp'] (Cp'=methylcyclopentadienyl) was confirmed by solid state (13)C magic angle spinning (MAS)-NMR spectroscopy. Subsequent reduction of the inclusion compound [Me(3)PtCp'](4)@MOF-177 by hydrogen at 100 bar and 100 degrees C for 24 h was carried out and gave rise to the formation of platinum nanoparticles in a size regime of 2-5 nm embedded in the unchanged MOF-177 host lattice as confirmed by transmission electron microscopy (TEM) micrographs and powder X-ray diffraction (PXRD). The room-temperature hydrogen adsorption of Pt@MOF-177 has been followed in a gravimetric fashion (magnetic suspension balance) and shows almost 2.5 wt % in the first cycle, but is decreased down to 0.5 wt % in consecutive cycles. The catalytic activity of Pt@MOF-177 towards the solvent- and base-free room temperature oxidation of alcohols in air has been tested and shows Pt@MOF-177 to be an efficient catalyst in the oxidation of alcohols.

Létoffé Jean-Marie

Papers

Reactions of lithium and sodium aluminium hydride with sodium or lithium hydride. Preparation of a new alumino-hydride of lithium and sodium LiNa2AlH6