Graphene quantum dots decorated MIL-100(Fe) composites for dye degradation

The present work outlines the synthesis of a visible light responsive photocatalyst by incorporating graphene quantum dots (GQD) in an iron-based metal organic framework (MOF) (i.e., MIL-100(Fe). The composite was synthesized via one-pot solvothermal approach and applied for degradation of Congo red (CR) dye from contaminated water. The composite was characterized in terms of structure, functionality, morphology, and optical properties. Noteworthy, the composite showed significant improvement in the photocatalytic activity in comparison with nascent MIL-100(Fe). Incorporation of GQD in the MOF framework resulted in increased surface area and pore volume and reduced PL intensity. MIL-100/GQD showed maximum dye degradation of 93.8% within 5 min of contact time using photocatalyst dose of 0.025 g/L. The incorporation of GQD resulted in increased charge separation between holes and electrons compared to pre MIL-100 (Fe) as evident from the PL spectra. The Mott-Schottky plot and the trapping experiment demonstrated that the active species like h+ and O2-were responsible for degradation of CR dye. The photocatalyst exhibited appreciable reusability even after four cycles of reuse.