CdSe QDs sensitized MIL-125/TiO2@SiO2 biogenic hierarchical composites with enhanced photocatalytic properties via two-level heterostructure

With increasing concern about the problems of environmental pollution and energy, the visible light photocatalytic for dye degradation is receiving considerable attention. CdSe quantum dot (CdSe QDs) sensitized MIL-125/TiO 2 @SiO 2 biogenic hierarchical materials (CMTS) has been fabricated through dual modification of CdSe with TiO 2 and MIL-125, that is the metal–organic framework (MOF) with Ti ions as metal centers and terephthalic acid as the organic ligand. The hierarchical porous heterostructured MIL-125/TiO 2 @SiO 2 composites are firstly obtained by a biogenic-templated method using rice husk as biomorphic. CdSe QDs as sensitizer is further deposited on MIL-125/TiO 2 @SiO 2 via a dipping method. This strategy applies CdSe, MIL-125, and TiO 2 undergo a two-level heterostructure, setting a stage for efficient charge separation. In addition, CMTS possesses a hierarchical porous structure in scale from micrometer to nanometer with high BET surface area. As a result, the CMTS can efficiently adsorption target, improving light harvesting and promoting degradation of organic waste from water. Meanwhile, Rhodamine B aqueous solution can be degraded more than 98% by CMTS in 100 min under visible light irradiation.