Morphology-controlled synthesis of Ni-B nanoparticles by addition of hydrogen peroxide

In this paper, H2O2 was used to control the morphology of Ni-B nanoparticles prepared by chemical reduction of nickel ethylenediamine complex. With increasing H2O2 concentration, Ni-B nanoparticle morphology progressed from pompon-like to sea urchin-like and finally to a flower-like shape. The controlled morphology was the result of dynamic equilibrium between the reduction of nickel ions by KBH4 and oxidation dissolution of Ni-B nanoparticles due to etching by H2O2. Additionally, the Ni-B catalyst nanoparticles had large BET areas and more uniform Ni active centers on the surface. However, excess H2O2 could disrupt the dynamic equilibrium, allowing the production of various structures of Ni-B nanoparticles. The catalyst composition with a molar ratio of 1:1 Ni ion to H2O2 showed the best activity toward electrocatalytic oxidation of ethanol. (C) 2017 Elsevier B.V. All rights reserved.