As a part of investigations of hydrogen storage materials, we have studied the Ti-Zr-Ni system, where it was discovered, that the atomic ratios influence the hydrogen absorption properties. Although these systems typically absorb around 1.5 mass % of hydrogen, we found a so-called »zero zone« area in the phase diagram, where the absorption is essentially zero. An analysis revealed that the surface oxide layer in the samples from the zero zone is significantly thicker in comparison to the samples outside the zone. By means of nuclear magnetic resonance, we have demonstrated that the electron density of state does not differ between both types of samples, therefore differences in the electronic structure cannot account for the different oxide layer formation.
COBISS.SI-ID: 24363559
We have studied hydrogen dymamics in cesium pentahydrogen diphosphate, CsH5(PO4)2. Our goal was to find out, why this particular system does not enter the superprotonic phase upon heating, in contrary to many related compounds that exhibit such phase. The analysis of spin-lattice relaxation time revealed activatione energies for different dynamic processes in the crystal (hydrogen hopping between hydrogen bonds and hydrogen hopping, assisted by PO4 tetrahedra rotations). Because of peculiar structure, the crystal melts upon heating even before the superprotonic phase appears.
COBISS.SI-ID: 24443687