Maximizing the hydrogen yield in the catalyzed hydrolysis of pure borohydride powders

Around 10 wt% H2 can be stored in a NaBH4 based system at ambient temperature and atmospheric pressure. The hydrogen is released when water is added to an excess of NaBH4(s)/cobalt (s)/NaOH(s) powder mixture. The heat evolved during the reaction increases the temperature from 25 up to 140 °C as monitored by an IR camera. This permits the formation of NaBO2·H2O with x ≈ 1/2, thermodynamically stable above 105 °C, rather than NaBO2·4H2O typically formed in excess water at room temperature. The presence of NaOH plays a crucial role in accelerating the reaction and increasing the temperature.