Pd and Pt nucleated nano Ni-particles: Evidence for heterogeneous nucleation and growth by transmission electron microscopy

Abstract

Transmission electron microscopy (TEM) study of mono-dispersed Ni-particles, prepared by the reduction of Ni(OH)2 in ethylene glycol with Pd/Pt as nucleating agent, has been carried out. Microstructural analysis employing bright-field and dark-field electron microscopy reveals polymicrocrystalline nature of each Ni-particle. TEM studies of Ni particles show presence of nearly 20 Å thick NiO layer over each 300 Å Ni-particles. Presence of 40 to 60 Å Pd/Pt nucleus has been confirmed in high magnification bright-field micrographs. The observed radial growth morphology supports heterogeneous nucleation of Pd/Pt over which Ni grows