Description: Hydrogen dynamics in Na3AIH6: A combined density functional theory and quasielastic neutron scattering study

This title appears in the Scientific Report : 2007

Hydrogen dynamics in Na3AIH6: A combined density functional theory and quasielastic neutron scattering study

Understanding the elusive catalytic role of titanium-based additives on the reversible hydrogenation of complex hydrides is an essential step toward developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed effects of doping sodium ala...

Personal Name(s):	Voss, J.
	Jacobson, H.S. / Zamponi, M. / Lefmann, K. / Vegge, T. / Shi, Q.
Contributing Institute:	JCNS; JCNS Streumethoden; IFF-4 Neutronenstreuung; IFF-5
Published in:	The @journal of physical chemistry / B, 111 (2007) S. 3886
Imprint:	Washington, DC Soc. 2007
Physical Description:	3886
PubMed ID:	17388555
DOI:	10.1021/jp0667036
Document Type:	Journal Article
Research Program:	Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) Kondensierte Materie
Series Title:	Journal of Physical Chemistry B 111
Subject (ZB):	Aluminum Compounds: chemistry Hydrogen: chemistry Models, Chemical Neutrons Quantum Theory Scattering, Radiation Sensitivity and Specificity Sodium Compounds: chemistry Temperature Aluminum Compounds Sodium Compounds Hydrogen J
	Publikationsportal JuSER

Please use the identifier: http://dx.doi.org/10.1021/jp0667036 in citations.

Understanding the elusive catalytic role of titanium-based additives on the reversible hydrogenation of complex hydrides is an essential step toward developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed effects of doping sodium alanate with TiCl3, and here we study hydrogen dynamics in doped and undoped Na3AlH6 using a combination of density functional theory calculations and quasielastic neutron scattering. The hydrogen dynamics is found to be vacancy mediated and dominated by localized jump events, whereas long-range bulk diffusion requires significant activation. The fraction of mobile hydrogen is found to be small for both undoped and doped Na3AlH6, even at 350 K, and improved hydrogen diffusion as a result of bulk-substituted titanium is found to be unlikely. We also propose that previously detected low-temperature point defect motion in sodium alanate could result from vacancy-mediated sodium diffusion.