Synthesis and characterisation of nanosized spinel particles of nickel-doped iron chromite

Nanoparticles of nickel-doped iron chromite (Fe1-xNixCr2O4) with composition x = 0.2-0.8 have been prepared by the sol–gel method using citric acid as a complexing agent. X-ray diffraction (XRD) results show that the synthesised doped nanoparticles are crystalline. Temperature and concentrations are key variables that influence nanopowder properties. To obtain fine powders, the doped samples were sintered at 750°C for 4 h. Doping was confirmed by XRD patterns. Raman spectra confirmed the existence of both parent and doped compounds. The band gap for the undoped sample is about 4.01 eV which, on doping, decreases to 3.7 eV as determined from photoluminescence spectra. The results suggest that synthesised nanoparticles of Fe1-xNixCr2O4 can be used for versatile future applications such as energy storage and photocatalytic activity.