Photocatalytic degradation of organic compounds in dye wastewater by Fe3+ doped nano-ZnO/TiO2 composite photocatalyst

Abstract

In this study, a Fe³⁺ doped ZnO/TiO₂ photocatalyst with optimized photocatalytic efficiency has been prepared using the calcination method. The synthesized photocatalyst has been comprehensively characterized using four analytical techniques:
X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). XRD analysis revealed the presence of TiO₂, ZnO, Fe₂O₃, and carbon in the photocatalyst composition. SEM imaging demonstrated that the particle size of the synthesized photocatalyst is at the nanometer scale. EDS results confirmed the successful doping of Fe³⁺ into the photocatalyst structure, with the photocatalyst surface exhibiting carbon enrichment. XPS analysis indicated that the combination of ZnO and TiO₂ promoted the formation of oxygen vacancies on the TiO₂ surface, thereby enhancing photocatalytic efficiency. Optimization experiments revealed that the best photocatalytic performance was achieved when the ratio of Zn (CH₃COO)₂, TiCl₄, FeCl₃·6H₂O, and oleic acid was 1:1:0.02:3, with a calcination temperature of 400 ℃. Under these conditions, the Fe³⁺ doped ZnO/TiO₂ photocatalyst exhibited superior photocatalytic efficiency. With the addition of 0.2 wt % Fe³⁺ to the ZnO/TiO₂ photocatalyst, the removal rates of methyl orange reached 90.68% and 97.14% after 4 h of exposure to incandescent lamp and sunlight, respectively.