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 (Fe 2 O 3 ) 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 Fe 2 O 3 , while the hydrothermal method was used to synthesize ST. To achieve optimal photocatalytic efficiency, the loading of Fe 2 O 3 onto ST was carefully controlled. The average crystallite size of ST, Fe 2 O 3 , and ST@Fe 2 O 3 (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@Fe 2 O 3 had a smaller direct bandgap (2.54 eV) compared to ST@0.3 Fe 2 O 3 (2.70 eV) and ST@0.5 Fe 2 O 3 (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@Fe 2 O 3 photocatalyst demonstrated superior performance compared to the other evaluated photocatalysts, completely degrading MB dye within just 60 min of solar light exposure. Incorporating Fe 2 O 3 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@Fe 2 O 3 appears to have a promising future as a practical photocatalyst for degrading various dye pollutants in wastewater.