Stability and decomposition of NaBH₄.

Martelli, Pascal; Caputo, Riccarda; Remhof, Arndt; Mauron, Philippe; Borgschulte, Andreas; Züttel, Andreas

doi:10.1021/jp909341z

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Journal article

Stability and decomposition of NaBH₄.

Martelli, Pascal Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf - Physics Department, University of Fribourg, Switzerland
Caputo, Riccarda Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf
Remhof, Arndt Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf
Mauron, Philippe Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf
Borgschulte, Andreas Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf
Züttel, Andreas Division of Hydrogen & Energy, Department of Mobility, Energy and Environment, EMPA, Dübendorf - Physics Department, University of Fribourg, Switzerland

26.03.2010

Published in:

The Journal of Physical Chemistry C. - 2010, vol. 114, no. 15, p. 7173-7177

English We investigate the stability and hydrogen desorption of NaBH₄. Dynamic pcT (pressure, concentration, and temperature) measurements under constant hydrogen flows are used to determine thermodynamic parameters of reaction. From the van’t Hoff equation the enthalpy and entropy of reaction, −108 ± 3 kJ mol⁻¹ of H₂ and 133 ± 3 J K⁻¹ mol⁻¹ of H₂ released, are obtained, respectively. This corresponds to a decomposition temperature of T_dec = 534 ± 10 °C at 1 bar of H₂. The decomposition thereby occurs in one step; i.e., only one plateau is visible in the pressure composition isotherms. Elemental Na is identified as the major solid component in the residue by X-ray diffraction. The experimental results are discussed on the basis of theoretical calculations using the density functional theory approach. Starting from the optimized structure of the cubic α-phase of NaBH₄, we discuss possible decomposition routes involving elemental Na and B as well as Na−H and Na−B binary compounds as residual products.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

Language