Hydrogen storage systems based on solid-state NaBH4/Co composite: Effect of catalyst precursor on hydrogen generation rate

Abstract Tablets on the basis of sodium borohydride and cobalt compounds (CoCl2·6H2O, Co(CH3COO)2·4H2O, Co3O4 and anhydrous CoSO4) have been studied as hydrogen generation materials. The kinetics of sodium borohydride hydrolysis upon contact of the tablets with water has been investigated. Adsorption and reaction constants have been determined for each of the catalysts using the Langmuir-Hinshelwood model which allowed us to estimate the contribution of BH4‾ adsorption to the overall rate of hydrogen generation. It was noted that the nature of the catalyst precursor has an influence not only on the specific surface area of the in situ forming catalytically active phase, the particle size of the catalyst, the degree of reduction of cobalt compounds by sodium borohydride but also on the adsorption of BH4‾ anions from the reaction medium on the catalyst surface.