CoB/open-CNTs catalysts for hydrogen generation from alkaline NaBH4 solution

CoB catalysts supported on carbon nanotubes with open tips (o-CNTs) were successfully prepared and used in hydrogen production from NaBH4 hydrolysis. The properties and morphologies of o-CNTs supports and CoB/o-CNTs catalysts were characterized by FT-IR, XRD, SEM–EDX and TEM, which showed that o-CNTs possess different organic functional groups and many open tips and CoB can be effectively loaded. Compared with CoB catalysts supported on carbon nanotubes with closed tips (c-CNTs), CoB/o-CNTs exhibit significantly higher hydrogen production rate of up to 3041 ml min−1 g−1 under the same conditions. In the experiment, the effect of CoB loading, catalyst supports, and operation temperature on hydrogen production rate was investigated in detail, which demonstrated that o-CNTs possess higher CoB loading than c-CNTs. It was shown that the apparent activation energy of CoB/o-CNTs is 37.63 kJ mol−1, which is obviously lower than 44.43 kJ mol−1 of CoB/c-CNTs.

► Open multi-walled carbon nanotubes were obtained via oxidation method. ► CoB catalysts were effectively loaded in o-CNTs and c-CNTs supports. ► CoB/CNTs possess higher CoB loading than CoB/c-CNTs. ► CoB/o-CNTs exhibit higher activity than CoB/c-CNTs in NaBH4 hydrolysis. ► Activation energy of CoB/o-CNTs is much lower than that of CoB/c-CNTs.