The present investigation focuses on a new synthesis route of NaBH4 starting from the 2NaH + MgB2 system subjected to mechanochemical activation under reactive hydrogen atmosphere. The milling process was carried out under two different hydrogen pressures of 1 and 120 bar with rotation speeds of 300 and 550 rpm, respectively. The reaction products were characterized by ex-situ solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR), ex-situ X-ray powder diffraction (XRPD) and Infrared Spectroscopy (IR). Both experiments led to the formation of NaBH4 (cubic-Fm-3m). In particular, a reaction yield of 5 and 14 wt. % is obtained after 20 hours of milling at 120 bar of H2 for the tests performed at 300 rpm and 550 rpm, respectively. The presence of MgH2 is also detected among the final products on the as milled powders. The influence of the milling conditions and the evaluation of the parameters related the mechanochemical process are discussed.
Mechanochemical synthesis of NaBH4 starting from NaH-MgB2 reactive hydride composite system
MILANESE, CHIARA;MARINI, AMEDEO;
2013-01-01
Abstract
The present investigation focuses on a new synthesis route of NaBH4 starting from the 2NaH + MgB2 system subjected to mechanochemical activation under reactive hydrogen atmosphere. The milling process was carried out under two different hydrogen pressures of 1 and 120 bar with rotation speeds of 300 and 550 rpm, respectively. The reaction products were characterized by ex-situ solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR), ex-situ X-ray powder diffraction (XRPD) and Infrared Spectroscopy (IR). Both experiments led to the formation of NaBH4 (cubic-Fm-3m). In particular, a reaction yield of 5 and 14 wt. % is obtained after 20 hours of milling at 120 bar of H2 for the tests performed at 300 rpm and 550 rpm, respectively. The presence of MgH2 is also detected among the final products on the as milled powders. The influence of the milling conditions and the evaluation of the parameters related the mechanochemical process are discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
