Impact of Ni Substitution on Structural, Electrical and Thermoelectrical Properties of Zinc Alluminium Chromites Synthesized by sol-gel Route and their Photocatalytic Investigation

Nanostructured nickel substituted zinc alluminium chromites (Zn1-x NixAlCrO4, where, x=0.0, 0.25, 0.50, 0.75, 1.0) were prepared by simple, cost effective, sol-gel autocombustion method. Temperature of phase formation was analyzed by thermogravimetric and differential thermal analysis (TGA/DTA). Crystallographic studies of all the samples show formation of single cubic spinel phase only. The lattice parameter, crystallite size and X-ray density decreases with increase in Nickel content. The surface morphology of Zn1-xNixAlCrO4 shows spherical interlinked morphology while elemental studies show desired composition. The nanosize of the synthesized material was confirmed by transmission electron microscopy (TEM) which was lies in between 19-25 nm. The DC conductivity as well as thermoelectric power studies of the samples reveals their semiconducting nature. The nanocrystalline chromite has optimal charge separation, which make them to enhance their photocatalytic efficiency. 0.100gm palladium loaded nickel alluminium chromite shows excellent mineralization in water.