An MOF-Graphene Interface for Efficient Electrochemical Sensing of Water-Soluble Organic Dyes

Differential detection and quantification of organic dyes in aqueous media are demonstrated utilizing an electrochemical method on a nanocomposite of UiO-66-NH₂ MOF deposited on graphene nanoplatelets (MOF@G). The selected organic dyes are anionic molecules with overlapping UV-vis absorption bands, which makes it cumbersome to detect, differentiate, and quantify each component in a solution mixture. The method presented herein provides for such detection and differentiation utilizing the tailored properties of the nanocomposite MOF@G, where the high porosity and adsorption capacity of the MOF toward soluble organic molecules, alongwith the high electronic conductivity of the G support, synergistically harnessed to provide a facile method for rapid and sensitive detection that can be further exploited toward other types of solution-based electrochemical detection of small organic molecules. A low detection limit of ∼2 ppm and a large dynamic linear range up to 12 ppm in an aqueous acidic solution are reported.