A comparative study of structural properties of oleic acid coated metal nanoparticles (Co, Ni, Fe) by co-precipitation method

Abstract

Metal nanoparticles of cobalt, nickel and iron were synthesized by chemical co-precipitation method using Sodium Borohydride as the reducing agent. The metallic particles were coated with oleic acid to prevent the formation of oxides on the surface layers. The structural analysis of both coated and uncoated samples were carried out using XRD technique and FTIR spectroscopy. XRD patterns of the uncoated samples showed the significant presence of oxide phases of the metallic nanoparticles while in the case of coated samples, the metallic phase was observed. A significant observation from the XRD patterns of the coated samples was the presence of a broad peak centred at 20–210 which is indicative of the graphitic structures typically observed as (002) reflections of graphite. However, the broadened peak depicted the formation of layered graphitic structures of Graphene/ nano tubes/fullerene/ nano onions. The stretching vibration of C = O and symmetric stretching vibrations of the –COO–functional group in the FTIR spectrum, indicated that the layer of oleic acid was successfully coated on the surface of MNPs. The graphitic structures of all oleic acid coated metal nanoparticles were confirmed by Raman spectroscopy. The formation of graphitic structure was the result of the catalytic action of metal nanoparticles..