Abstract
Functionalized zinc oxide (fZnOFe3O4) was synthesized and grafted to the epoxy (∼C-O) groups of graphene oxide (GO) to develop the fZnOFe3O4@GO composites. The Fourier transform infrared spectrometer provided initial evidence confirming the successful grafting of fZnOFe3O4 to the ∼C-O groups of GO. To this effect, bands for the ∼C-O groups were not observed on the C1s orbital of the fZnOFe3O4@GO composites, while they were present in the C1s orbital of GO at 286 eV, as indicated by the X-ray photoelectron spectroscopy. Because of the composite's improved physical and chemical properties, the band gap energy of GO and ZnO was tuned from Eg, 2.5 and 3.3 eV, respectively, to 1.75 and 1.08 eV in the fZnOFe3O4 and fZnOFe3O4@GO composites, respectively; degradation efficiency above 95 % was observed for methylene blue and Congo red dye molecules with the fZnOFe3O4 and fZnOFe3O4@GO composites. In the case of textile industry wastewater, the fZnOFe3O4@GO composite exhibited a degradation efficiency of 64 % with a corresponding decay constant (k) of −1.04867 under ultraviolet light irradiation. In contrast, fZnOFe3O4 NPs demonstrated a removal capacity of only 19 % (k: −0.20909). The improved surface area, thermal stability, reduced band gap, and lower photoluminescence intensity render the composites valuable in sustainable applications.
•Functionalized zinc oxide was grafted onto graphene oxide's epoxy groups•GO's band gap was tuned without using harsh chemicals or high temperatures•Enhanced photon absorption and emission observed in the UV and visible regions.