Combination of Chemical Hydride Hydrogen Generation System with Low-Temperature PEMFCs

Abstract

High purity hydrogen generated by hydrolysis of sodium borohydride can be used as the fuel of PEM fuel cell and other portable device. As its high hydrogen storage capacity, controllable reaction and mild condition, hydrogen generation by catalytic hydrolysis of chemical hydride, such as sodium borohydride, has been the major focus of researches. On the threshold of the controllable of hydrogen generated by hydrolysis of sodium borohydride, the catalyst for hydrolysis of hydrogen generation (HG) is studied. First, applying chemical plating, Ru/Ni foam catalyst was prepared; then, continuous flow reactor method was used to generate hydrogen. Varied parameters, such as concentrations of NaBH4 and NaOH, flow rate of NaBH4 solution and quantity of catalyst, were inspected in this research. It was found that, the NaBH4 and NaOH concentration at 20wt% and 3wt%, fuel feed to 4 g/min, hydrogen yield of 1.72 L/min, the hydrogen production efficiency as high as 91.2%. The present hydrogen generator was integrated with a 100W PEMFC and the optimum performance of the integrated system was studied. The hydrogen produced from NaBH4 has high purity and humidity; therefore, it can be directly used as the fuel for PEMFCs, which in general require humidified hydrogen. It is found that for cell voltage above 0.6V, the performance of cell using NaBH4 hydrogen is 103.45W, versus 99.9W with cylinder hydrogen.