TiO2 Nanofibers Decorated with Ag Nanoparticles and {P2W18}-Type Polyoxometalate Nanoclusters for Photodegradation of Organic Pollutants

The development of effective and stable photocatalysts for water treatment remains a significant challenge in environmental remediation. In this work, {P2W18}-type polyoxometalate (POM) cluster and Ag nanoparticles (NPs) are monodispersed on internal and external surfaces of TiO2 nanofibers by electrospinning and solvothermal methods. P2W18@TiO2–Ag-6.12 exhibits the most efficient separation of photogenerated electron–hole pairs and the highest photocatalytic activity. The P2W18/TiO2–Ag of this ratio shows efficient and continuous activity for the photodegradation of 2,4-dichlorophenol (2,4-DCP) and the degradation of salicylic acid in the presence of a peroxydisulfate system under ultraviolet (UV) irradiation with a maximum degradation efficiency of 96.63% for 2,4-DCP and 84.67% for salicylic acid within 60 and 30 min, respectively. The reaction pathways and mechanism of photocatalytic processes were studied in detail. Results indicate that TiO2 nanofibers prevent Ag NP agglomeration, increase POM surface area, and improve composite stability. The synergistic effect of the three materials enhances electron–hole separation and transport, reduces band gap width and redox potential, and boosts photocatalytic efficiency. This work offers a strategy for developing efficient, stable nanoheterojunction catalysts for environmental remediation.