Capping Agent Assisted and Ag-Catalyzed Growth of Ni Nanoflowers

Abstract

Capping agent (triethanolamine (TEA), diethanolamine (DEA), ethylene glycol (EG)) assisted silver-catalyzed nickel particles with flowerlike morphology has been synthesized using nickel(II) chloride hexahydrate as a precursor and hydrazine hydrate as a reducing agent by simple heating at 60 °C for 10 min. X-ray diffraction studies confirmed that the synthesized nickel is highly crystalline with face centered cubic structure. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images revealed the formation of a nickel nanoflower irrespective of the capping agent used. High resolution transmission electron microscopy (HRTEM) of the single petal obtained in the presence of TEA shows that the fringes are equispaced with a lattice separation of 0.203 nm corresponding to the (111) plane of the fcc nickel. When the same reaction is performed at 40 and 80 °C, cauliflower-like morphology of the nickel nanoparticles and horn spheres of nickel are formed respectively. A mechanism has been proposed for the growth of nickel nanoparticles with the progress of the reaction based on scanning electron microscopy (SEM) and TEM. The nickel nanoparticles exhibit ferromagnetic behavior with the remnant magnetization being maximum using DEA as the capping agent in comparison to the values reported so far in the literature.