Hydrogen generation by hydrolysis of solid sodium borohydride for portable PEMFC applications

Abstract

In this paper, the hydrogen generation by the hydrolysis of solid sodium borohydride was studied. A novel NiCoP/RC catalyst that loads Ni, Co, and P complexes on resin carbon (RC) was prepared to accelerate the hydrolysis. The hydrogen generation rate, reaction temperature, hydrogen output and water-hydrogen ratio during the reaction were recorded. In comparison to the commonly used cobalt chloride catalyst, the NiCoP/RC catalyst demonstrated superior catalytic activity. Citric acid was used to neutralize the alkaline by-products, and while the mixture of NiCoP/RC catalyst and citric acid increased the hydrogen output, it resulted in lower water utilization rate. Therefore, intermittent water feeding from the bottom of the reactor was proposed, which was found to be beneficial in terms of both hydrogen output and water utilization. Finally, the study warns about the potential for thermal runaway during the hydrolysis reaction of solid sodium borohydride.