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 NH 2 -MIL-125(Ti) modified manganese dioxide (MnO 2 @ NH 2 -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 MnO 2 successfully adheres and grows on the NH 2 -MIL-125(Ti) frameworks, changing the micromorphology while increasing the yield. In particular, when the NH 2 -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 MnO 2 . 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. Graphical Abstract Highlights A simple hydrothermal method is used to obtain the oxidant MnO 2 @ NH 2 -MIL-125(Ti). The sample MnO 2 @ NH 2 -MIL-125(Ti)-15% exhibits the optimum oxidation performance of 95.8% for RhB. The oxidation of the sample to RhB is augmented under acidic conditions (pH = 3). Propose growth mechanism of oxidant MnO 2 @ NH 2 -MIL-125(Ti) and degradation mechanism of RhB.