Facile synthesis of solar light active spinel nickel manganite (NiMn2O4) by co-precipitation route for photocatalytic application

The spinel nickel manganite (NiMn2O4) nanoparticles (NPs) were successfully synthesized through simple co-precipitation method, and their structural, optical, morphological and photocatalytic behavior is examined in this investigation. The powder X-ray diffraction pattern confirms the face-centered cubic spinel structure of the as-prepared sample, and the average crystallite size is found to be 46.27 nm. The absorption spectrum of the material was obtained via diffuse reflectance spectroscopy (UV-DRS), and the bandgap value is calculated using Tauc's relation as 2.41 eV. Morphological analysis was investigated by using a scanning electron microscope (SEM). From the SEM analysis, the hexagonal cake-like structure was observed from the prepared material and size was achieved around to be 50-100 nm. Furthermore, the photocatalytic behavior of NiMn2O4 (NPs) against organic dyes under direct sunlight was analyzed by using methylene blue, malachite green and Congo red and the efficiency is observed as 92%, 94% and 62%, within 120 min, 60 min and 120 min, respectively.