Hydrogen generation and storage from hydrolysis of sodium borohydride in batch reactors

The catalytic hydrolysis of alkaline sodium borohydride (NaBH₄) solution was studied using a non-noble; nickel-based powered catalyst exhibiting strong activity even after long time storage. This easy-to-prepare catalyst showed an enhanced activity after being recovered from previous use. The effects of temperature, NaBH₄ concentration, NaOH concentration and pressure on the hydrogen generation rate were investigated. Particular importance has the effect of pressure, since the maximum reached pressure of hydrogen is always substantially lower than predictions (considering 100% conversion) due to solubility effects. The solubility of hydrogen is greatly enhanced by the rising pressure during reaction, leading to storage of hydrogen in the liquid phase. This effect can induce new ways of using this type of catalyst and reactor for the construction of hydrogen generators and even containers for portable and in situ applications.