Low cost fabrication of continuous flow optofluidic microreactor for efficient dye degradation using graphene QDs@MOF (Ti) photocatalyst

The optofluidic microreactor, a convergence of optics and microfluidics, offers advanced functionalities that can be pivotal in the rapid assessment of nanocatalysts for tackling environmental contamination issues. This article presents an efficient approach for degrading Methylene blue (MB) dye, commonly used in the textile industry, within a cost-effective polydimethylsiloxane (PDMS) based continuous flow optofluidic microreactor. This microreactor combines graphene quantum dots (QDs) and NH2-MIL-125 (MOF(Ti)) as a highly effective photocatalyst coating within its microchannels. By directly incorporating graphene QDs@MOF(Ti) into the microchannels, the photocatalytic medium is brought into close proximity with the flowing MB dye solutions, thereby reducing the necessary interaction time and enhancing purification efficiency. Furthermore, the findings demonstrate an impressive degradation efficiency of ∼99% for MB dye at a flow rate of 50 μL min−1 under visible light irradiation, achieved in a single pass. Additionally, the microfluidic reactor exhibits prolonged stability of the photocatalyst, enabling its reuse without significant efficiency loss. In addition, a comparative analysis highlights the advantages of microreactor-based photocatalysis over traditional methods. These advancements in the features of the graphene QDs@MOF(Ti) nanocomposite substantiate their demonstrated superiority in degradation efficiency.