NaBH4 is a candidate for H2 storage in solid phase. NaBH4 hydrolysis readily produces H2
gas and NaBO2 which can regenerate NaBH4 with pressurized hydrogen and the aid of a
reducing agent like Magnesium above 500 C. This paper deals with the NaBH4 thermochemical
regeneration from the NaBO2eMgeH2 ternary system at isothermal temperatures
between 558 and 634 C and H2 pressure in the range 2e31 bar. A simplified Langmuir
adsorption model has been applied for the interpretation of the in-situ H2 pressure variations.
The applied model is zero-dimensional but provides a reasonable approach to
identify the rate determining step and acquire relevant thermodynamic and kinetic parameters
such as equilibrium constant (Keq), Gibbs free energy (DrG0) and reaction rate
coefficients (k). The study provides an apparent activation energy and Gibbs free energy of
this process of 29.2 kJ/mol and 76.9 kJ/mol, respectively.