In situ Raman and neutron spectroscopy of complex hydrides

摘要

The search of suitable hydrides for hydrogen storage can benefit from Raman and neutron spectroscopy, especially when it is possible to exploit these diagnostic techniques in situ, that is, in controlled conditions of gas pressure and temperature. In this way it is possible to observe and monitor phase transitions or sample chemical decomposition. In our laboratory we have studied the vibrational spectrum of several complex hydride compounds both at cryogenic temperature (15 K) and during or after thermal treatment at high temperature (up to 600 K), in a controlled atmosphere. In particular, in this talk I will present the results of the characterization of bulk samples of Mg(BH4)2 and AlH3 where the proportions of the different phases can be changed by different thermal treatments. Additionally, both Raman and neutron spectra of Na3AlH6, recorded at low temperature, have disclosed the presence of low frequency lattice modes, that have been compared with computational results.