Catalytic behavior of carbon supported Ni-B, Co-B and Co-Ni-B in hydrogen generation by hydrolysis of KBH4

Activated carbon (AC) supported Ni-B, Co-B, and Co-Ni-B catalysts with different Co/Ni mass ratios were synthesized by impregnation of commercial activated carbon with the solution of cobalt and/or nickel salt, and then reduction of metal salts with sodium borohydride at room temperature. Structural properties and morphology of the catalysts were studied using inductively coupled plasma (ICP), XRD and SEM techniques. The B content of the catalyst is less than that required for stoichiometric alloy formation, which indicates the simultaneous presence of the Co and/or Ni metal along with Co-B and/or Ni-B alloy on the surface of activated carbon. The catalytic activity of the catalysts has been tested by measuring the hydrogen generation rate during the hydrolysis of potassium borohydride in basic medium. The results show that Co-B/AC exhibits the highest activity among Ni-B/AC, Co-B/AC and Co-Ni-B/AC catalysts investigated. For supported bimetallic boride catalysts, the catalytic activity increases with Co/Ni mass ratio. The effects of reaction parameters, such as KBH4 concentration, NaOH concentration, and reaction temperature, on the reaction were also surveyed. (C) 2011 Elsevier B.V. All rights reserved.