Hydroxyapatite prepared from biomineral calcium carbonate resources: a Ru-catalyst support for hydrogen generation

In this study, we hydrated calcines of biomineral calcium carbonate resources such as eggshells and scallop shells and converted them to hydroxyapatite (HAp) under different conditions for use as Ru catalyst supports. The catalytic activity of Ru/HAp in the hydrolysis of sodium borohydride was investigated by measuring the volume of hydrogen gas generated from the alkaline solution at 298 K. The results clarify that, when different calcium sources are used as starting materials, high Ru content does not always produce high catalytic activity. The hydrogen generation rate is closely correlated with average pore size of the catalyst. High-performance catalysts obtained in the present study have average pore sizes of 20 nm or less and a molar ratio Ca/P of approximately 1.60.