Kinetics of hydrogen generation on NaBH4 powders using cobalt catalysts

Hsin-Yi Kao, Chia-Chi Lin, Chien-Ju Hung, Chi-Chang Hu

Index: 10.1016/j.jtice.2018.03.022

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Abstract

The hydrogen generation kinetics for the hydrolysis reaction of a solid mixture consisting of sodium borohydride powders and Co catalyst prepared by mechanical grinding are investigated in this work. The hydrolysis reaction for hydrogen generation has been conducted in a fuel cartridge with variations in the catalyst content (0.0063, 0.0111, and 0.0158 g) and hydrolysis temperature (25, 35, and 45 °C). The hydrogen generation data are fitted with the zero-order and first-order kinetic models. The results reveal the importance of initial reaction temperature and heat removal during the hydrolysis and that the monotonous increase in the reaction temperature caused by the excess heat generated from this exothermic reaction leads to uncontrollable and unpredictable hydrolysis rates. This drawback can be circumvented by effective heat removal through the thermal management in the fuel cartridge, prolonging the operating period of the fuel cell stack (> 3 h).