Catalytic hydrojen production from alkali sodium borohydride solutions

Sodium borohydride (NaBH4) is the most important chemical for hydrogen storage. A recent trend for hydrogen production is its controlled production from hydrolysis of NaBH4 using some catalysts. In this study, the purpose was controlled hydrogen production from NaBH4. Effects of NaBH4 (0,5*10-4 g/ml ? 12,5*10-4 g/ml) and NaOH (1-15 %) concentration, catalyst type (3,2 mm alumina pellets; Pt-0,5wt%; Pt-1wt%; Pd-0,5wt%; Ru-0,5wt%; Rh-0,5wt%) and amount of them, solution flow rate and temperature on hydrogen production were studied. Hydrogen production was slightly increased with increasing NaBH4 concentration and amount of catalyst within the experimental range studied in preliminary experiments. Therefore, all other experiments were performed with 0,6*10-4 g/ml NaBH4 and 3 g catalysts. NaOH concentration was changed in the range of 1-15 % in the experiments and the highest hydrogen production rate was observed with 10 % NaOH concentration. In addition, hydrogen production was also increased with increasing solution flow rate and temperatures. Similar hydrogen production rates were observed for all catalysts studied. Because of low price, Pt-0.5 wt% catalyst was preferred in the study. There was not a big difference in production efficiencies which were observed to be in the range of 64-85 %. NaOH concentrations which yield the highest hydrogen production were also determined for each catalyst.