A novel visible-light-driven In-based MOF/graphene oxide composite photocatalyst with enhanced photocatalytic activity toward the degradation of amoxicillin

A novel MIL-68(In)-NH2/graphene oxide (GrO) composite was prepared as a visible-light-driven photocatalyst for the degradation of amoxicillin (AMX). The MIL-68(In)-NH2/GrO composite exhibited much higher photocatalytic activity than pure MIL-68(In)-NH2. Using 0.6 g L−1 MIL-68(In)-NH2/GrO and pH = 5, 93% degradation and 80% TOC removal toward AMX could be achieved after irradiation time of 120 and 210 min, respectively. The enhanced activity for MIL-68(In)-NH2/GrO can be attributed to the modification by using GrO, which not only acted as electron transporters for suppressing the photogenerated carrier recombination, but also played as a sensitizer for enhancing visible light absorption. Further experiments revealed that the solution pH had a significant impact on the photodegradation of AMX. In addition, MIL-68(In)-NH2/GrO possessed good reusability and stability. Finally, the enhanced photocatalytic mechanism over MIL-68(In)-NH2/GrO was also proposed, and h+ and O2− were further determined to be the main active species in the photocatalytic system.