Photocatalytic Degradation of Zn─Ti─O Nanocomposites Prepared by Sol–Gel Method

ABSTRACT Organic dye effluents from industrial processes pose severe toxicological and environmental threats, necessitating the development of highly efficient technologies for wastewater treatment. In this study, zinc titanate (Zn–Ti–O) nanopowders were synthesized using a facile sol–gel method. The effects of calcination temperatures (500°C–800°C) on the crystal phase structure, morphology, optical properties, and photocatalytic performance under visible‐light irradiation were systematically investigated. As the calcination temperature increased from 500°C to 800°C, the crystal phase transformed from pure Zn 2 TiO 4 to a ternary composite of Zn 2 Ti 3 O 8 , ZnTiO 3 , and Zn 2 TiO 4 . Results demonstrated that the sample obtained at 800°C exhibited the highest degradation efficiencies, achieving 89.5% for methylene blue (MB) and 80.3% for crystal violet (CV) within 120 min of irradiation. Additionally, the optimized composite showed effective degradation capabilities toward Congo Red (CR), Rhodamine B (RhB), and tetracycline (TC). This superior behavior was attributed to its unique multi‐phase heterojunction structure and optimized band‐gap position, which facilitates the efficient migration and separation of photogenerated electrons and holes, thereby enhancing the generation of reactive oxygen species. Furthermore, after three consecutive cycles, the photocatalyst demonstrated excellent stability. This study provides a valuable experimental foundation and theoretical reference for their applications in photocatalysis.