Controlling Metal Clusters in Breathing Metal-Organic Framework Nanostructures for Boosting Visible-Light-Induced ·oH Radical Formation

In recent years, traces of pharmaceuticals with high environmental risks have been reported in water cycles. Conventional wastewater treatment processes are largely ineffective in eliminating these micropollutants. Advanced wastewater treatment processes have great potential to achieve high removal rates. Thus, metal cluster (Fe-oxo, Al-oxo, and Cr-oxo)-induced ROS formation via heterogeneous catalysts was explored in an antibiotic degradation process. In this study, we synthesized a series of MIL-53 with one-dimensional photo-induced mixed-valence metal chains containing three selected clusters. Results show that the advanced oxidation performance is highly metal-dependent. Fe-oxo and Cr-oxo can significantly promote the photo-Fenton process. Also, Al-oxo can serve as a promising heterogeneous Fenton-like catalyst. Systematical characterizations of these materials were given including UV-vis DRS, Tauc's plot, and transient photocurrent analysis. Fe/Cr-based metal-organic frameworks convey obvious visible-light photo-Fenton performance by excellent light absorption properties and high ROS production ability with an averaged separated metal atom center. The Al-based one can promote acetaminophen degradation by the formation and decomposition of H₂O-H₂O₂substitution coordinated to an Al atom. All these isostructural materials can promote the acetaminophen degradation process effectively by boosting ·OH production.