Temperature-Dependent Properties and 2,4-Dichlorophenol Photocatalytic Activity of SrTiO3–Al

Abstract Strontium titanate (SrTiO 3 ) doped with aluminum (Al) to modify its bandgap and enhance charge carrier performance is used as a photocatalyst. However, the structure of SrTiO 3 –Al often leads to low crystallinity and poor uniformity, creating charge traps that promote recombination and reduce photocatalytic efficiency. This study explored the effects of different annealing temperatures (950 °C, 1050 °C, 1150 °C, and 1250 °C) on the structural and optical properties of SrTiO 3 –Al synthesized via the flux method. Structural characteristics were analyzed by using X-ray diffraction, energy dispersive X-ray, and field-emission scanning electron microscopy. Optical characteristics were observed through UV–vis diffuse reflectance spectroscopy, whereas photocatalytic activity was measured on the basis of the degradation of 2,4-dichlorophenol (2,4-DCP) under UV light. Among samples, that annealed at 950 °C exhibited the highest photocatalytic performance, achieving a 2,4-DCP degradation rate of 11% under UV irradiation within 180 min. This sample had 3-fold higher activity than pristine SrTiO 3 because of its small particle size; high surface area; and extensive (110) crystallographic plane exposure that promotes effective charge separation.