Halloysite nanotube-based cobalt mesocatalysts for hydrogen production from sodium borohydride

We report the novel hybrid metal-clay mesocatalysts with halloysite nanotubes as carriers and cobalt as catalytic metal for hydrogen production from sodium borohydride. The ligand assisted metal adsorption on the surface of halloysite and intercalation into nanotubes was achieved using azines or silane. The catalyst with pre-formed cobalt oxide nanoparticles adsorption on the pristine halloysite surface showed low catalytic efficiency. The most active cobalt-containing system was formed using ketazine as the ligand. The chelating agent selection strongly affected the hydrogen evolution process and was optimized. The best halloysite based core-shell mesocatalyst contained 16 wt% of cobalt with maximum hydrogen evolution rate of 3 L/minxg(cat).