Enhanced performance of Pt and Pt–Ru supported PEDOT–RGO nanocomposite towards methanol oxidation

• Pt and Pt–Ru supported PEDOT–RGO nanocomposites are prepared by electrochemical method.
• Their electrocatalytic activity for methanol oxidation is assessed with respect to PEDOT/Pt and RGO/Pt.
• PEDOT–RGO/Pt has a high specific surface area and shows the best performance.
• The effects of Pt loading, methanol concentration and electrode stability are studied.
• The kinetics of methanol oxidation at variable Ru loading is investigated.

The electrocatalytic performance of reduced graphene oxide-poly(3,4-ethylenedioxythiophene)/platinum (RGO–PEDOT/Pt) nanocomposite for methanol oxidation has been evaluated with respect to PEDOT/Pt and RGO/Pt. The electrocatalysts are characterized by scanning electron microscopy, transmission electron microscopy and cyclic voltammetry. The RGO–PEDOT/Pt has been found to have favorable characteristics in terms of large specific surface area (460.5 m2 g−1) and small particle size (0.61 nm). The methanol oxidation current for RGO–PEDOT/Pt is nearly 3.6 and 12.6 times higher than that for PEDOT/Pt and RGO/Pt respectively. Among the three electrocatalysts, the RGO–PEDOT/Pt nanocomposite shows the best electrocatalytic behavior towards methanol oxidation with a mass specific peak current of 774 mA mg−1 cm−2 for a Pt loading of 191.4 μg cm−2 at a concentration of 1 M methanol in 0.5 M H2SO4. The effects of Pt loading, methanol concentration and electrode stability have been studied. RGO–PEDOT/Pt–Ru electrodes with a fixed Pt and variable Ru ion concentrations are prepared by chronoamperometry and the Pt–Ru alloy formation was confirmed by X-ray diffraction method. The electrocatalytic performance of the Pt–Ru supported RGO–PEDOT for the oxidation of methanol is evaluated by cyclic voltammetry. The Tafel kinetic analysis indicates that the RGO–PEDOT/Pt–Ru prepared with equal concentrations of Pt and Ru ions (i.e. RGO–PEDOT/Pt–Ru (1:1)) gives the best performance in terms of the lowest onset potential (0.14 V), highest exchange current density (2390 μA cm−2) and highest If/Ir ratio (2.33) implying minimum poisoning.