Influencing Optical and Magnetic Properties of NiCr2O4 by the Incorporation of Fe(III) for Cr(III) Following Epoxide Gel Synthesis

摘要： With the objective of modifying the optical and magnetic properties of the spinel NiCr2O4, incorporation of 50 mol.% of Fe3+ for Cr3+ has been attempted following an epoxide-mediated gel synthesis. From the Le Bail re?nement of powder x-ray diffraction patterns of xerogels after calcination at 1000°C for 2 h in Fd-3 m space group, the lattice parameter of resultant spinels showed a marginal increase from 8.3117 (21) for NiCr2O4 to 8.3177 (26) A? for NiCrFeO4. The square morphology of the crystallites was observed in scanning electron microscopic images, and the energy-dispersive spectroscopy results con?rmed the uniform presence of Ni, Cr and Fe in these samples. Lattice fringes in high-resolution transmission electron microscopic images could be related to the cubic spinel structure. The optical band gap was found to decrease from 1.68 for NiCr2O4 to 1.41 eV for NiCrFeO4. Substitution of iron for chromium was found to reduce its catalytic ef?ciency for photo-degradation of aqueous rhodamine-6G (Rh-6G) dye solution under UV–visible radiation.