A multifactor study of catalyzed hydrolysis of solid NaBH4 on cobalt nanoparticles: Thermodynamics and kinetics

In the present work, hydrogen generation through hydrolysis of a NaBH4(S)/catalyst((S)) solid mixture was realized for the first time as a solid/liquid compact hydrogen storage system using Co nanoparticles as a model catalyst. The performance of the system was analysed from both the thermodynamic and kinetic points of view and compared with the classical catalyzed hydrolysis of a NaBH4 solution. The kinetic analysis of the NaBH4(S)/catalyst((S))/H2O(1) system shows that the reaction is first order with respect to the catalyst concentration, and the activation energy equal to 35 kJ mol(NaBH4)(-1). Additionally, calorimetric measurements of the heat evolved during the hydrolysis of NaBH4 solutions evidence the global process energy (-217 kJ mol(NaBH4)(-1)). Characterization of the cobalt nanoparticles before and after the hydrolysis associated with the calorimetric measurements suggests the "in situ" formation of a catalytically active CoxB phase through "reduction" of an outer protective oxide layer that is regenerated at the end of reaction. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.