Cobalt nanoparticles supported on magnetic core-shell structured carbon as a highly efficient catalyst for hydrogen generation from NaBH4 hydrolysis

Abstract

A novel recyclable cobalt nanocatalyst, supported on magnetic carbon with core-shell structure, was successfully synthesized by using wetness impregnation-chemical reduction method for hydrogen generation from hydrolysis of NaBH4. The resultant nanocomposite was characterized to determine the structural and physical-chemical properties by a series of analytical techniques such as FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy-dispersive X-ray spectroscopy), TEM (transmission electron microscopy), etc. The results demonstrated that amorphous cobalt nanoparticles were homogeneously surrounded on the surface of the support due to having abundant hydrophilic groups (such as aldehyde and hydroxyl groups) on the surface of carbon layer for the effective immobilization of metal ions. The supported catalyst showed superior catalytic performance towards the hydrolysis reaction of NaBH4 at room temperature. The total rate of hydrogen generation and activation energy were calculated to be 1403 ml H2 gcat−1 min−1 and 49.2 kJ mol−1, respectively, which were comparable to the values of most cobalt-based catalyst reported for hydrogen production from hydrolysis of NaBH4. Additionally, reusability test revealed that the hydrogen in NaBH4 substrate could be completely released within 25 min with a minimum hydrogen generation rate of 832 ml H2 gcat−1 min−1 even after five runs of hydrolytic reaction, implying the as-prepared Co/Fe3O4@C composite could be considered as a promising candidate catalyst for portable hydrogen fuel system such as PEMFC (proton exchange membrane fuel cells).