Format

Send to

Choose Destination
See comment in PubMed Commons below
J Chem Phys. 2007 May 14;126(18):184703.

Ab initio investigation of ammonia-borane complexes for hydrogen storage.

Author information

  • 1Department of Materials Sciences and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Abstract

The structural, electronic, and thermodynamic properties of ammonia-borane complexes with varying amounts of hydrogen have been characterized by first principles calculations within density functional theory. The calculated structural parameters and thermodynamic functions (free energy, enthalpy and entropy) were found to be in good agreement with experimental and quantum chemistry data for the crystals, dimers, and molecules. The authors find that zero-point energies change several H2 release reactions from endothermic to exothermic. Both the ammonia-borane polymeric and borazine-cyclotriborazane cycles show a strong exothermic decomposition character (approximately -10 kcal/mol), implying that rehydrogenation may be difficult to moderate H2 pressures. Hydrogen bonding in these systems has been characterized and they find the N-H bond to be more covalent than the more ionic B-H bond.

[PubMed]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Institute of Physics
    Loading ...
    Write to the Help Desk