Verification of Appropriate Temperature Range of Acid Accelerant in Hydrogen Generation System from NaBH4

Abstract

Sodium borohydride (NaBH4) generates hydrogen by hydrolysis of powdery NaBH4. The hydrogen generation rate is accelerated with the use of an acid solution as an accelerant when the system is started up in low temperature. In addition, it was confirmed that no short-term degradation arises in the characteristics of 5 kW stack of fuel cells, even if rapid hydrogen generation system with adding an acid accelerant was used. However, the effectiveness to use an acid accelerant in high temperature has never examined; therefore, an appropriate temperature range in which the acid accelerant is effectively acting has not been determined. So, this research clarified the appropriate temperature range obtaining the sufficient reaction acceleration rate of an acid accelerant in high temperature. A result of the experiment using the hydrogen generation system showed that the reaction acceleration rate of the acid accelerant decreased with rising reaction temperature. In addition, the result also showed that the hydrogen generation rate with the acid accelerant was lower than the rate without the acid accelerant at 95°C.