Synthesis and photocatalytic investigation of ZnFe2O4 in the degradation of organic dyes under visible light

Zinc ferrites (ZnFe2O4), with spinel-like structure, were produced by combustion reaction synthesis in solution and heat-treated at temperatures of 400–1100 °C. The structural and chemical properties of the ZnFe2O4 samples were investigated by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), Field Emission Gun Scanning Electron Microscopy (FEG-SEM) with X-ray dispersive spectroscopy (EDS), and diffuse reflectance spectroscopy (DRS) in the ultraviolet (Uv–vis) region. The photocatalytic performance of this compound was investigated in order to evaluate the green malachite and rhodamine B dyes degradation under visible irradiation. The XRD patterns results reveal the presence of cubic ZnFe2O4 at all heat-treated temperatures and pure phase above 800 °C. The presence of spherical and porous agglomerate morphology was confirmed through SEM analysis. Absorption bands between 400 and 600 cm−1 in the infrared spectra confirmed the presence of the ferrite phase. Diffuse reflectance results on the ZnFe2O4 samples showed that absorption occurred in the visible light range. The best temperature of the photocatalytic degradation performance of the dyes was 400 °C. This was more pronounced for the green malachite dye when compared to rhodamine B due to secondary phases and smaller crystal sizes.