Hydrogen production from sodium borohydride in boric acid-water mixtures

Borohydride, which reacts slowly with water, is developed as hydrogen production and storage options. The reaction is significantly accelerated by the rise of temperature or by the addition of acidic substances. Boric acid (H ₃BO₃) can be used as an alternative to water for the hydrogen production in the hydrolysis of sodium borohydride (NaBH₄). The effect of H₃BO₃ and NaBH₄-H ₃BO₃ molar ratios was studied at 30, 40, 50, 60, and 80°C on the hydrogen production of NaBH₄. All of these results show that H₃BO₃ is a relatively green acid compound for hydrogen generation from NaBH₄ and the H₃BO ₃-water-NaBH₄ system being quite simple for single-use applications. It was found that the reaction between H₃BO₃ and NaBH₄ complied with a second order kinetics rate with 0.5 reaction orders versus NaBH₄ concentration and 1.5 ordersversus H₃BO₃ concentration, and the activation energy for conversion was calculated as 18.01 kJ mol^-1.