Metal-Organic Framework Functionalized Sulphur doped Graphene: A Promising Platform for selective and sensitive Electrochemical Sensing of Acetaminophen, Dopamine and H2O2

We present a simple in-situ self-assembly approach for crafting of a heteroatom doped graphene supported Metal-Organic-Framework (MOF) nanocomposite; a highly conductive redox active 2D platform with excellent potential for selective and sensitive electrochemical sensing of biologically important molecules. The hybrid nanocomposite comprises of 1,4-benzene dicarboxylic acid organic linker based Cu-MOF self-assembled over sulfur doped graphene nanosheets (S-Gr). Our detailed structural characterization and electrochemical investigations carried over the so crafted Cu-MOF@S-Gr composite suggest that S-Gr sheets besides inducing a directional growth of MOF crystals, endows this nanohybrid with plentiful of electroactive sites. The synergism among the Cu-MOF and S-Gr components and the presence of too many electroactive sites facilitate faster heterogeneous electron transfer and mass transfer thereby imparting the Cu-MOF@S-Gr with excellent conductivity, electrocatalytic activity and electroanalytical utility. The excellent electroanalytical utility of Cu-MOF@S-Gr hybrid nanocomposite was explored toward selective and sensitive sensing of acetaminophen (AC), dopamine (DA) and H2O2. We demonstrate that with the use of Cu-MOF@S-Gr hybrid nanocomposite, AC and DA can be electrochemically sensed with a resolution of 2.22 and sensitivity of 0.85µA/µM.cm2 and 0.58µA/µM.cm2 respectively in the concentration range of 2 µM to 98 µM and 10 µM to 80 µM with detection limits as low as 12.00 ±0.05 nM and 37.00 ±0.06 nM respectively. We also demonstrate that with Cu-MOF@S-Gr hybrid H2O2 can be electrochemically sensed in the concentration range as low as 0.1µM-3.0µM with an extremely low detection limit of 11.3±0.04 nM and very high sensitivity of 63.82µA/µM.cm2. We opine that the presented study shall stimulate an intense research activity towards the design of highly sensitive, selective and stable MOF based electroanalytical devices.