Sodium titanium oxide/zinc oxide (STO/ZnO) photocomposites for efficient dye degradation applications

Abstract

Abstract In this study, sodium titanium oxide (Na2Ti3O7, termed STO) and sodium titanate/zinc oxide (STO/ZnO) photocomposites were prepared for the first time. A low-cost hydrothermal technique was employed to fabricate the STO/ZnO photocomposites with varying ZnO weight ratios: STO/0.25ZnO, STO/0.5ZnO, and STO/ZnO. The prepared photocomposites were investigated for the decomposition of methylene blue dye (MB) under natural visible light illumination and an artificial tungsten halogen lamp. The STO/ZnO photocomposite exhibits high photodegradation performance, which can be correlated with its properties and characterization. The X-ray diffraction analysis reveals that STO has an average crystallite size of 69.1 nm, ZnO has an average crystallite size of 41.4 nm, and the combination of STO/ZnO results in a reduced average crystallite size of 39.5 nm. The bandgap (E g) of STO/ZnO is 2.53 eV after controlling the ZnO weight ratio. The photocatalytic efficiency of the STO/ZnO photocomposite was 100% for MB within 60 min of solar light irradiation, compared to 33.7% for STO and 25.8% for ZnO. The effect of STO/ZnO dosage and MB concentration was investigated. Furthermore, the kinetics and mechanisms of the photocatalytic process were examined. The results suggest that STO/ZnO has promising potential for practical applications in wastewater treatment.