Green sol–gel synthesis of CoMnCrO 4 spinel nanoparticles and their photocatalytic application

CoMnCrO 4 spinel nanoparticles were prepared using the green and efficient sol–gel method. The synthesised nanoparticles were fully characterised by Fourier‐transform infrared spectroscopy, X‐ray powder diffraction with Rietveld refinement, transmission electron microscopy, scanning electron microscopy, and diffuse reflectance spectroscopy analysis. The characterisation of the sample showed that the CoMnCrO 4 NPs have a spinel cubic structure with a crystallite size of 14 nm, narrow bandgap (1.75 eV), and uniform spherical morphology with particle size about 25–30 nm. The CoMnCrO 4 NPs demonstrated high photocatalysis capability towards the Congo red dye as a pollutant with a high and fast efficiency degradation of 90% after 30 min under the visible light irradiation. Also, the impacts of different parameters consisting of nanoparticle amount, initial dye concentration, irradiation time, light and dark on dye degradation efficiency were assessed.