Photocatalytic degradation of organic pollutants using yttrium and copper co-doped nickel aluminate

Abstract Spinel nickel aluminate was synthesized using the sol-gel process and citric acid as a capping agent. Parent nickel aluminate, yttrium-doped nickel aluminate, and yttrium-copper co-doped nickel aluminate were synthesized and calcined at 800 °C for 4 hours. The synthesized spinels were used to enhance photocatalytic activity and can convert harmful organic dyes into simpler, less harmful molecules like CO2 and H2O. The synthesized nanoparticles were characterized by various techniques, including XRD, UV-DRS, XPS, and SEM-EDAX. X-ray diffraction analysis helped in understanding the purity of phases, the lattice parameter, and the determination of average crystallite size. UV-DRS gave vital information about electronic property, i.e., band gap, by utilizing the Tauc plot method. The morphology of the nanoparticles was characterized by SEM (scanning electron microscopy), whereas elemental confirmation in the nickel aluminate lattice was carried out by EDAX. XPS provided information on the oxidation states of the ions present in the spinels. Photocatalysis was conducted against the organic dye crystal violet. Yttrium-doped nickel aluminate exhibited a higher photocatalytic activity in comparison to undoped nickel aluminate. This suggested improved activity in photocatalysis due to the insertion of yttrium into the lattice. Parameters such as pH, the effect of catalyst dosage, and the effect of concentration of dye were analyzed.