Ti-enhanced kinetics of hydrogen absorption and desorption on NaAlH4 surfaces

Abstract

We report a first-principles study of the energetics of hydrogen absorption and desorption (i.e. H-vacancy formation) on pure and Ti-doped sodium alanate (NaAlH4) surfaces. We find that the Ti atom facilitates the dissociation of H2 molecules as well as the adsorption of H atoms. In addition, the dopant makes it energetically more favorable to creat H vacancies by saturating Al dangling bonds. Interestingly, our results show that the Ti dopant brings close in energy all the steps presumably involved in the absorption and desorption of hydrogen, thus facilitating both and enhancing the reaction kinetics of the alanates. We also discuss the possibility of using other light transition metals (Sc, V, and Cr) as dopants.

arXiv comment4 pages with 2 postscript figures embedded. Uses REVTEX4 and graphicx macros. More information at http://www.ncnr.nist.gov/staff/taner

References in corpus (7)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Titanium-decorated carbon nanotubes: a potential high-capacity hydrogen storage medium
• Molecular and dissociative absorption of multiple hydrogens on transition metal decorated C60
• X-ray absorption study of Ti-activated sodium aluminum hydride
• Multi-phonon scattering and Ti-induced hydrogen dynamics in sodium alanate
• First-principles study of Ti-doped sodium alanate surfaces

Cited by in corpus (1)

• Dynamics and Thermodynamics of a Novel Phase of NaAlH4