Abstract Kinetic experiments were carried out on the hydrolysis of concentrated aqueous and aqueous alkaline solutions of NaBH4 with a Co/TiO2 catalyst. The experiments in the aqueous NaBH4 solutions were performed at molal concentrations of 0.25, 1, and 4 mol/kg. In the aqueous alkaline solutions with molal NaBH4 concentrations of 0.25 and 1 mol/kg, the molal NaOH concentrations were varied in the range 0.05–8 mol/kg. The activation energies in the aqueous solution and the aqueous alkaline solutions were found to be 64.3 and 53.6 kJ/mol, respectively. Features of the kinetic curves and the possible kinetic schemes were discussed.