Synthesis, structure and hydrogenation properties of Ni-Cu bimetallic nanoparticles

Bimetallic Ni-Cu nanoparticles with different (Ni/Cu) ratio have been synthesized via fast and simple one-pot reducing Ni(OH)2/Cu(OH)2 pulp by hydrazine in water/ethylene glycol solutions. Using scanning electron microscopy (SEM), it was found that all obtained nanopowders are polydisperse with the particles sizes within 20–70 nm and the mean diameter of particles slightly depends on the Ni/Cu ratio. Using XRD phase-structural analysis, it was found that with increasing Cu amount in the initial mixture from 20 to 50%, the lattice parameter for Ni phase increases from 3.527 to 3.560 Å but the lattice parameter of Cu changes more slightly (3.594 … 3.606 Å). Besides, using precision EDX technique, it was found that obtained nanoparticles may be considered as a core–shell type in which a core consists of copper but a shell consists of a nickel-copper solution. Hydrogenation properties of obtained Ni-Cu nanoparticles have been studied, and it has been shown that the initial capacity of Ni-Cu-NPs depends on the specific surface area and compositions of the samples.