Synthesis and study of structural, optical and magnetic properties of Ni3P–Ni compounds nanoparticles: The effect of reduction and complexing agents

In this paper, nanostructured nickel-phosphide compounds: (a) nanosheets, (b) nanoflowers-like and (c) polyhedral nanoparticles have been prepared by chemical reduction method. The effect of reduction agents: (a) sodium hypophosphite and (b) sodium borohydride and annealing at T = 450 °C under argon (Ar) gas on the structural, optical and magnetic properties of compounds have been investigated. The prepared samples were analyzed by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM), UV–Vis spectroscopy and the vibrating sample magnetometer (VSM). The X-ray diffraction results of nanosheet and polyhedral nanoparticles samples showed that before annealing, they had an amorphous structure and after annealing, a combination of three (Ni3P), (Ni) and NiO phases and Ni single phases appeared. Surface morphology were examined by (FE-SEM) images and it was found that particles were flat and nanosheet before annealing and nanoflowers-like after annealing. The band gap of nanosheet nanoparticle is increased after annealing from 5.86 eV to 6.0 eV and polyhedral nanoparticles is reduced after annealing from 5.24 eV to 2.80 eV. The magnetic properties of the sample also showed that before annealing the nano-powders had paramagnetic property and after annealing, they became soft ferromagnetic.