ISOBAM-stabilized Ni2+ colloidal catalysts: high catalytic activities for hydrogen generation from hydrolysis of KBH4.

ISOBAM-104-stabilized Ni2+ colloidal catalysts were synthesized through a facile method and used for hydrogen generation from hydrolysis of potassium borohydride (KBH4). Ni nanoparticles (NPs) were formed as the active phase during the catalytic process. Ultraviolet-visible spectrophotometry (UV-vis) and transmission electron microscopy were employed to characterize the structure and particle size of the as-formed Ni NPs. The results suggested that the catalytic activity of Ni2+ colloidal catalyst increased with the decreased size of as-formed Ni NPs, which is consistent with the results of density functional theory calculation. The highest catalytic activity of the catalyst can be 12400 ml-H2 min-1 g-Ni-1, which was even higher than that of noble Pt or Pd colloidal catalysts prepared using identical methods and catalytic conditions. According to the Arrhenius method, the ISOBAM-104-stabilized Ni2+ colloidal catalysts showed low activation energies of about 41.3 kJ mol-1 for the hydrogen generation from hydrolysis basic KBH4 solution.