Electrochemical Sensing of Monohydric Alcohols on Different Linkers Imbedded in Between Graphene and Platinum Nanoparticles.

We investigated the relationship between the linker's length and the electrooxidation of methanol and ethanol with PtNPs-decorated graphene oxide (GO). The covalently functionalized materials were prepared with three different lengths of the alkane chain as the linker molecules in between GO and platinum nanoparticles (PtNPs). Electrochemically reduced GO-S-(CH₂)n-S-Pt [ERGO-S-(CH₂)n- S-Pt, wherein n = 2, 3 and 4] was obtained via electrochemical reduction of GO-S-(CH2)1-S-Pt in PBS at pH 5. ERGO-S-(CH₂)n-S-Pt was characterized by XPS and FE-SEM. The XPS result reveals that the Pt at% increased with the increasing of chain length and the surface morphology indicates the surface area increased with the increasing of linker's length. The electrochemical behavior of these modified glassy carbon electrodes (GCEs) were investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry (CA). The ERGO-S-(CH₂)n-S-Pt was employed to detect methanol and ethanol; and the ERGO-S-(CH₂)₄-S-Pt showed a better performance towards alcohol oxidation reaction (AOR) among all ERGO-S-(CH₂)n- S-Pt. The detection limit of methanol and ethanol was 1.8 x 10⁻² mM and 1.28 x 10⁻² mM, respectively, at ERGO-S-(CH₂)₄-S-Pt.