A composite of borohydride and super absorbent polymer for hydrogen generation

To develop a hydrogen source for underwater applications, a composite of sodium borohydride and super absorbent polymer (SAP) is prepared by ball milling sodium borohydride powder with SAP powder, and by dehydrating an alkaline borohydride gel. When sodium polyacrylate (NaPAA) is used as the SAP, the resulting composite exhibits a high rate of borohydride hydrolysis for hydrogen generation. A mechanism of hydrogen evolution from the NaBH4–NaPAA composite is suggested based on structure analysis by X-ray diffraction and scanning electron microscopy. The effects of water and NiCl2 content in the precursor solution on the hydrogen evolution behavior are investigated and discussed.

Research highlights▶ A new composite material composed of sodium borohydride, sodium hydroxide and sodium polyacrylate for the borohydride hydrolysis to generate hydrogen is prepared by ball milling. ▶ Water content and NiCl2 content in the catalyst precursor solution significantly affect the hydrogen generation kinetics of the composite. ▶ A hydrogen evolution mechanism of the composite is suggested.