A multifactor study of catalyzed hydrolysis of solid NaBH 4 on cobalt nanoparticles: Thermodynamics and kinetics

Abstract

In the present work, hydrogen generation through hydrolysis of a NaBH 4(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 NaBH 4 solution. The kinetic analysis of the NaBH 4(s)/catalyst (s)/H 2O (l) 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 NaBH 4 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 Co x B phase through “reduction” of an outer protective oxide layer that is regenerated at the end of reaction.