Effective binding of MOF and TiO2 particles: A novel composite material capable of rapidly methylene blue

This study fabricated a novel MIL-88A/TiO₂ composite photo-Fenton catalyst through a one-step hydrothermal method for efficient degradation of Methylene Blue (MB) in organic dye wastewater. MIL-88A, leveraging its visible-light responsiveness and high specific surface area, significantly enhanced the composite material's light absorption range (extended to 600 nm) and photogenerated charge separation efficiency when composited with TiO₂. Characterizations via XRD, FTIR, SEM, and XPS confirmed the successful combination of TiO₂ and MIL-88A in the composite. The conduction band potential (−0.59 eV) and valence band potential (1.88 eV) of MIL-88A/TiO₂ were well-matched, promoting efficient separation of electron-hole pairs. Photo-Fenton experiments revealed that under pH 3.0 and 5 mM H₂O₂ dosage, the composite could completely degrade 50 mg/L MB solution within 10 min, with degradation efficiency significantly superior to single components. Radical trapping experiments and ESR analysis indicated that hydroxyl radical(OH) and electrons (e−) were the dominant active species, and the reaction mechanism involved photo-generated electron-driven Fe³⁺/Fe²⁺ redox cycling and H₂O₂ decomposition to produce reactive radicals. In addition, the material maintained a degradation efficiency of over 95 % after five cycles and exhibited good structural stability. The stable performance of MIL-88A/TiO₂ in a wide pH range (3.0–9.0) and in the actual environment with co-existing ions further highlights its application potential. This study provides new insights into the development of efficient and stable photo-Fenton catalytic materials.