Biogenic Hierarchical MIL-125/TiO2 @SiO2 Derived from Rice Husk and Enhanced Photocatalytic Properties for Dye Degradation.

The hierarchical porous heterostructured MIL-125/TiO2 @SiO2 composites are successfully obtained by biogenic-templated method using rice husk both as biomorphic. The products are characterized by X-ray diffraction, N2 -adsorption-desorption analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The results reveal that MIL-125/TiO2 @SiO2 possesses a hierarchical porous structure in scale from micrometer to nanometer with high Brunauer-Emmett-Teller (BET) surface area (385.7-902.7 m2 g-1 ). The photocatalytic mechanism was discussed in detail. Meanwhile, the activity of MIL-125/TiO2 @SiO2 for the photocatalytic degradation of rhodamine B in aqueous medium is significantly higher than that of P25. The current work provides some concept and methods in the development of MOF-based photocatalysts.