Interface engineering of UiO-66-derived ZrO₂@TiO₂/Ag(AgCl) multiphase heterostructure for enhanced UV-driven...

Efficient separation and transport of photogenerated charge carriers remain key challenges in wide-bandgap semiconductor photocatalysts. Herein, a UiO-66-derived ZrO₂@TiO₂/Ag(AgCl) multiphase composite was fabricated through a solvothermal-calcination route and evaluated for UV-driven dye degradation and photo-disinfection. X-ray diffraction, electron microscopy, Fourier-transform infrared spectroscopy, and UV-visible diffuse reflectance spectroscopy verified the coexistence and intimate interfacial coupling of ZrO₂, TiO₂, Ag, and AgCl domains. The composite exhibited an apparent optical bandgap of 4.24 eV and enhanced UV-responsive photocatalytic activity. Relative to the reference samples, the optimized composite showed a lower charge-transfer resistance (10.85 Ω), quenched photoluminescence emission, and an approximately 1.9-fold higher transient photocurrent response, supporting improved overall photoinduced carrier transport and extraction. The measured component band-edge potentials provide a thermodynamic framework for a proposed Ag-mediated interfacial charge-transfer model, while the photoelectrochemical behavior and reactive-species trapping results support improved carrier dynamics and the participation of reactive oxygen species. Within this proposed model, Ag-containing interfaces are hypothesized to facilitate selective interfacial recombination, thereby preserving charge carriers with strong redox capability. However, the present measurements do not directly resolve the phase-specific locations or migration directions of photogenerated carriers. Because the trapping experiments were conducted in the presence of H₂O₂, which can act as an electron acceptor and contribute to additional reactive-oxygen-species-generating pathways, the individual origins of •OH and •O₂^- cannot be uniquely assigned. Under the tested UV-irradiation conditions, the optimized composite achieved 97.8% methylene blue degradation within 4 h in the presence of 1.75% H₂O₂, exhibited activity toward methyl orange, rhodamine B, and rhodamine 6G, and showed photoinduced antibacterial activity against Escherichia coli and Staphylococcus aureus at 5 mg mL^- 1. The photocatalyst maintained a degradation efficiency of 83.98% after five consecutive cycles. These results demonstrate the potential of UiO-66-derived multiphase heterostructures as multifunctional UV-driven photocatalysts for dye degradation and photo-disinfection.