Enhanced Electrocatalytic Performance for Methanol Oxidation via Insertion of Ruthenium Oxide Particles into Pt and Polyaniline-Poly(Acrylic Acid-co-Maleic Acid) Composite Electrode

Polyaniline (PANI) is doped with poly(acrylic acid-co-maleic acid) (PAMA) containing HCl to obtain PANI-PAMA film. Ultraviolet-visible spectroscopy results confirm the doping of PANI with PAMA and HCl. A scanning electron microscopy image reveals that the film is composed of highly porous nanowires. Platinum (Pt) particles are deposited into the PANI-PAMA film via electrochemical deposition to obtain PANI-PAMA-Pt composite electrodes. Subsequently, ruthenium oxide (RuO2) particles are incorporated into the composite electrodes by cyclic voltammetry for 20 and 60 cycles to obtain PANI-PAMA-Pt-RuO220 and PANI-PAMA-Pt-RuO260 composite electrodes, respectively. The existence of RuO2 particles is confirmed via characterization by X-ray photoelectron spectroscopy. X-ray diffraction analysis explains a decrease in the number of Pt crystalline facets for the incorporation of RuO2 into PANI-PAMA-Pt, indicating a strong interaction between Pt and RuO2. Cyclic voltammetry results and chronoamperometric response measurements demonstrate that the PANI-PAMA-Pt-RuO220 electrode has the best activity and stability toward methanol oxidation among the three electrodes.