Copolymers based on indole-6-carboxylic acid and 3,4-ethylenedioxythiophene as platinum catalyst support for methanol oxidation

Abstract

Indole-6-carboxylic acid (ICA) and 3,4-ethylenedioxythiophene (EDOT) are copolymerized electrochemically on a stainless steel (SS) electrode to obtain poly(indole-6-carboxylic acid-co-3,4-ethylenedioxythiophene)s (P(ICA-co-EDOT))s. The morphology of P(ICA-co-EDOT)s is checked using scanning electron microscopy (SEM), and the SEM images reveal that these films are composed of highly porous fibers when the feed molar ratio of ICA/EDOT is greater than 3/2. Platinum particles can be electrochemically deposited into the P(ICA-co-EDOT)s and PICA films to obtain P(ICA-co-EDOT)s-Pt and PICA-Pt composite electrodes, respectively. These composite electrodes are further characterized using X-ray photoelectron spectroscopy (XPS), SEM, X-ray diffraction analysis (XRD), and cyclic voltammetry (CV). The SEM result indicates that Pt particles disperse more uniformly into the highly porous P(ICA3-co-EDOT2) fibers (feed molar ratio of ICA/EDOT = 3/2). The P(ICA3-co-EDOT2)-Pt nanocomposite electrode exhibited excellent catalytic activity for the electrooxidation of methanol in these electrodes, which reveals that P(ICA3-co-EDOT2)-Pt nanocomposite electrodes are more promising for application in an electrocatalyst as a support material.