Tyramine Functionalized Graphene: Metal-Free Electrochemical Non-Enzymatic Biosensing of Hydrogen Peroxide

We report here non-enzymatic electrochemical biosensing of H2O2 using a highly stable, metal-free, tyramine functionalized graphene (T-GO) based electrocatalytic system. The surface functionalization of tyramine on graphene was carried out chemically. The obtained sheets were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) as well as X-ray photoelectron (XP), Raman, FT-IR and UV-visible spectroscopy. More significantly, the combined results from morphological and structural studies show the formation of a few layers of graphene with effective large-scale functionalization by tyramine. As a metal-free electrocatalyst, the as-synthesized T-GO shown good electrocatalytic activity towards reduction of H2O2 with a sensitivity of 0.105 mM/cm(2) confirmed by combined results from cyclic voltammetric (CV) and linear sweep voltammetric (LSV), and amperometric (i-t) measurements. The lower onset potential (-0.23 mV vs SCE), lower detection limit, wider concentration range (10 mM to 60 mM) with higher electrochemical current and potential stability demonstrated the potential of our non-enzymatic and cost-effective T-GO based electrocatalytic system towards reduction of hydrogen peroxide.