In-Situ generation of nano TiO₂ from MIL-125(Ti) and its role in boosting the photocatalytic degradation of tetracycline hydrochloride

Metal-organic frameworks (MOFs), such as MIL-125(Ti), are advanced photocatalytic materials due to their tunable compositions and functionalities. However, their practical application in photocatalysis is often limited by their wide bandgap and the inherent structural instability. This study presents a strategy to improve the photocatalytic performance of MIL-125(Ti) by hydrothermal reaction combined with an in-situ decomposition to generate nano TiO₂, creating a composite with g-C₃N₅ nanosheets. The obtained composite exhibited a rate constant of 0.00122 min⁻¹ mg⁻¹ for the degradation of tetracycline hydrochloride under visible light irradiation, which is 24.4 and 20.3 times that of g-C₃N₅ and MIL-125(Ti), respectively. Characterization results indicated the formation of an effective composite structure that improved the separation efficiency of photogenerated carriers and promoted the generation of reactive oxygen species. The in-situ generated TiO₂ within the MIL-125(Ti)/g-C₃N₅ composite during the preparation and photocatalysis processes not only compensated for the structural damage to the original MIL-125(Ti) but also significantly enhanced its degradation performance under visible light. The recyclability and stability of the composite material were also demonstrated, highlighting its potential for practical photocatalytic applications.