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. (paper)