In context of investigations of doped sodium alanate as a hydrogen storage material, an investigation combining a TEM-EDX study and XAFS measurements has been carried out on doped sodium alanate, using titanium tetrabutylate (Ti(OBuⁿ)₄), colloidal titanium nanoparticles (Ti*) or TiCl₃ as doping agents. It was found that the dehydrogenated wet-chemically Ti(OBuⁿ)₄ doped NaAlH₄ consists of a crystalline Al and an amorphous NaH phase. The striking result of EDX analyses is that in each case the Ti-dopant is found to be present only in the Al phase. On the other hand, dehydrogenated NaAlH₄ doped with Ti* or TiCl₃via ball milling is an amorphous material, with diffuse boundaries between Al and NaH phases and a highly uniform distribution of titanium in the Al-phase. Both the use of the ball milling doping method and of Ti* nanoparticles as dopants, are probable reasons for the outstanding kinetics of the Ti* doped material (B. Bogdanović, M. Felderhoff, S. Kaskel, A. Pommerin, K. Schlichte and F. Schüth, Adv. Mater., 2003, 15, 1012; M. Fichtner, O. Fuhr, O. Kircher and J. Röthe, Nanotechnology, 2003, 14, 778). The course of hydrogen dis- and recharging reactions is discussed in light of the present TEM-EDX and the preceding XRD investigations of storage materials. Ti-EXAFS and XANES spectra of Ti-doped NaAlH₄ after the doping, after several, and after 100 de- and rehydrogenation cycles are very close to each other. Apparently, after the Ti-doping, a zerovalent Ti species is formed which remains almost unchanged in the course of the cycle test. The XAFS spectra indicate that Ti is largely atomically dispersed in the Al phase, i.e. forms an Al–Ti alloy, thus confirming the earlier hypothesis (V. P. Balema, J. W. Wiench, K. W. M. Dennis, M. Pruski and V. K. Pecharsky, J. Alloys Compd., 2001, 329, 108; E. H. Majzoub and K. J. Gross, J. Alloys Compd., 2003, 356–357, 363) on this matter.

Change in local atomic environment during crystallization of Zr-based glassy alloys was studied by extended x-ray absorption fine structure (EXAFS) spectroscopy. The formation of icosahedral quasicrystalline phase followed by crystallization of tetragonal ${\mathrm{CuZr}}_2$ has been observed in the ${\mathrm{Zr}}_{70}{\mathrm{Cu}}_{29}{\mathrm{Pd}}_1$ glassy alloy during annealing up to 850 K. On the other hand, the binary ${\mathrm{Zr}}_{70}{\mathrm{Cu}}_{30}$ alloy shows a single glassy to crystalline ${\mathrm{CuZr}}_2$ phase transformation. The local atomic environment of as-quenched ${\mathrm{Zr}}_{70}{\mathrm{Cu}}_{30}$ alloy is matched to an icosahedral local atomic configuration, which is similar to that of the as-quenched ${\mathrm{Zr}}_{70}{\mathrm{Cu}}_{29}{\mathrm{Pd}}_1$ alloy and the alloy annealed at 593 K containing icosahedral phase. Considering that the supercooled liquid region appears prior to crystallization in the ${\mathrm{Zr}}_{70}{\mathrm{Cu}}_{30}$ glassy alloy, the observed results support the theory claiming a strong correlation between the existence of local icosahedral short-range order and stability of the supercooled liquid state.

In order to identify active sites on ZnO powdered catalysts in methanol synthesis a total of five ZnO samples with different degrees of crystallinity were characterized by means of N₂ physisorption, XRD, TEM, and EXAFS. With respect to catalysis, high-pressure methanol synthesis was performed as a test reaction. A linear area-activity relationship for the highly crystalline materials was obtained, but at high BET surface areas a strong deviation from linearity was found. The observed phenomena provide evidence for a structure-sensitivity, suggesting that a specific active site is favored for methanol formation. Based on earlier work with polycrystalline ZnO powder and with respect to the current theoretical and experimental work with ZnO single crystals, the polar ZnO faces are assumed to be highly relevant for the catalytic activity under methanol synthesis conditions.