Electrocatalytic Behavior of Carbon Nanotubes in Electropolymerizations of Self-Doped Polyaniline Used as a Sensing Material

Abstract

Electrochemically oxidative copolymerizations on indium tin oxide electrode of aniline (AN) and o-aminobenzene sulfonic acid (OSA) with mole ratio of 25/75 in the presence of carbon nanotubes (CNT) and acid-treated CNT (fCNT) were conducted to investigate the electrocatalytic effects of the nanotubes on the copolymerizations. The P(25AN-co-75OSA)/CNT and P(25AN-co-75OSA)/fCNT composites were subsequently investigated into their electrocatalytic activities to the redox reactions of Fe(CN)63−/4− as a probe in aqueous solutions of different pH and detection capacities for dopamine (DA) and ascorbic acid (AA) by cyclic voltammetry. The results revealed that CNT and fCNT both electrocatalyzed the oxidations during the copolymerizations of P(25AN-co-75OSA), with CNT having a higher electrocatalytic capacity than fCNT. The so-prepared composites exhibited electrocatalytic activity for the redox reactions of Fe(CN)63−/4− in solutions of up to pH 7, with fCNT having a higher electrocatalytic activity than CNT. The P(25AN-co-75OSA)/fCNT composite film was able to detect DA and AA, exhibiting diffusion-controlled electron transfer rate.