The effect of various factors on the hydrogen generation by hydrolysis reaction of potassium borohydride

Potassium borohydride (KBH₄) reacted very slowly with water to liberate 4 mol of hydrogen/mol of compound at room temperature. The hydrolysis and stability conditions of KBH₄ investigated depend on KBH₄ concentrations, concentration of alkaline solutions, temperatures and electrical field intensity. Yield of produced hydrogen by self-hydrolysis of KBH₄ increases as the temperature increased and it produced 53.9% yield at the end of 300 min at 60 °C. The reaction rate order of hydrolysis of KBH₄ in aqueous solution is found at about 0.7-0.8 and the activation energy for hydrolysis is calculated as 14,700 kJ/mol. Potassium borohydride is stable both in room temperature and in aqueous alkaline solution. In this study, the electrical field that is not needed for catalytic activity was used for the hydrolysis of KBH₄ aqueous solution. It was found that 6 mol of hydrogen/mol of potassium borohydride was liberated in the presence of electrical field, whereas 4 mol of hydrogen was produced in the absence of electrical field per mol of potassium borohydride.