Magnetic Ni/Ag core–shell nanostructure from prickly Ni nanowire precursor and its catalytic and antibacterial activity

Abstract

A microemulsion template assisted hydrazine hydrate mediated wet chemical reduction of nickel chloride hexahydrate at 70 °C has been used for the fabrication of prickly nickel nanowires. Subsequently, the nanowire surfaces are modified with silver using the well known Tollen's reagent to form Ni/Ag core–shell nanostructures. X-Ray diffraction studies confirm the formation of face centered cubic type structures of nickel as well as silver in Ni/Ag nanostructures individually and they are found to be devoid of any trace of contamination. Low magnification field emission scanning electron microscope (FESEM) images confirm the wire-like morphology of nickel as well as Ni/Ag core–shell nanostructures. However, the high magnification FESEM and transmission electron microscopy images show the prickly surface of nickel nanowires consisting of cone-like nanostructures, where small spherical silver particles are deposited. Vibrating sample magnetometer (VSM) studies show well defined ferromagnetic behavior of the Ni as well as core–shell Ni/Ag structures. In addition, these nanostructures have been proved to be efficient catalysts at room temperature for the reduction of p-nitrophenol compared to bare Ni nanowires, and the magnetic behaviour serves as an added advantage in its easy separation from the reaction mixture so that it can be reused. Furthermore, Ni/Ag nanostructures also exhibit excellent antibacterial properties, which are significantly better than commercially available antibacterial materials.