Composite NH₂-MIL-125(Ti) to modulate the microstructure of MnO₂ and improve oxidation properties

In this paper, we employed a hydrothermal method to synthesize different ratios of NH₂-MIL-125(Ti) modified manganese dioxide (MnO₂@ NH₂-MIL-125(Ti)) and explored the effect of pH and mass fraction on the degradation of Rhodamine B. The characterization (XRD, XPS, SEM) of the material proves that MnO₂ successfully adheres and grows on the NH₂-MIL-125(Ti) frameworks, changing the micromorphology while increasing the yield. In particular, when the NH₂-MIL-125(Ti) is introduced at a ratio of 15%, the composite sample reveals optimal degradation performance, with a rate of Rhodamine B degradation as high as 95.8% in 40 min, which is about 1.6 times better than that of pure MnO₂. And it can perform superior oxidation performance under acidic conditions. The increased active sites due to the introduction of the framework structure and the higher redox potential under acidic conditions are the main reasons for the improved oxidative properties. In addition, we put forward a mechanism of growth and oxidative degradation for the composite sample for this phenomenon.