NH2-MIL-125(Ti)/amorphous TiO2 microspheres for enhanced visible light photocatalytic selective oxidation of amines

Metal–organic frameworks (MOFs) have received increasing attention for conducting miscellaneous photocatalytic reactions. Amorphous TiO 2 , despite the lack of visible light activity, can be a platform for integrating with a Ti-based MOF NH 2 -MIL-125(Ti) during hydrothermal process. Herein, amorphous TiO 2 microspheres are synthesized to enhance the activity of NH 2 -MIL-125(Ti) by integration. The morphology, porosity, and activity of NH 2 -MIL-125(Ti)/amorphous TiO 2 microspheres are systematically investigated by various methods. The photocatalyst NH 2 -MIL-125(Ti)/amorphous TiO 2 exhibits enhanced conversions, more than five times that of pristine NH 2 -MIL-125(Ti), for the selective oxidation of benzylamine. A series of optical and electrochemical characterizations are performed to clarify the mechanism for the photocatalytic selective oxidation of benzyl amines. Specifically, for NH 2 -MIL-125(Ti)/amorphous TiO 2 , visible light absorption is from NH 2 -MIL-125(Ti); and faster electron transfer to molecular oxygen is due to amorphous TiO 2 . This work shows that integrating MOFs with metal oxides can be crucial in enhancing visible light photocatalysis .