Sodium titanate nanostructured modified by green synthesis of iron oxide for highly efficient photodegradation of dye contaminants

Abstract

Abstract In this study, sodium titanate (ST)/iron oxide (Fe2O3) was successfully prepared as a novel binary photocatalyst for the first time to enhance the photocatalytic activity. The prepared photocatalyst was used in the photodegradation of methylene blue (MB) dye under sunlight and a tungsten lamp. The green synthesis method using orange peel extract was employed to prepare Fe2O3, while the hydrothermal method was used to synthesize ST. To achieve optimal photocatalytic efficiency, the loading of Fe2O3 onto ST was carefully controlled. The average crystallite size of ST, Fe2O3, and ST@Fe2O3 (with a 1:1 wt% ratio) was 999.8, 81.9, and 104 nm, respectively, using the Williamson–Hall (W–H) model. Optical analysis revealed that ST@Fe2O3 had a smaller direct bandgap (2.54 eV) compared to ST@0.3 Fe2O3 (2.70 eV) and ST@0.5 Fe2O3 (3.24 eV). The photodegradation of MB was analyzed considering the weight of the photocatalyst, the irradiation time, and the dye concentration. In-depth explanations of stability and kinetic models were also provided. Remarkably, the ST@Fe2O3 photocatalyst demonstrated superior performance compared to the other evaluated photocatalysts, completely degrading MB dye within just 60 min of solar light exposure. Incorporating Fe2O3 into ST effectively reduces the recombination of photo-produced electron/hole (e/h) pairs and broadens the response range of the solar spectrum. Based on these findings, ST@Fe2O3 appears to have a promising future as a practical photocatalyst for degrading various dye pollutants in wastewater.