Enhanced electrochemical reversibility of ultrathin aniline oligomer films grown on Pt(111)

Aniline adsorption and the first stages of aniline polymerization on a Pt(111) single-crystal electrode are studied. At low monomer concentration the aniline oxidation process leads to the appearance of two highly reversible redox couples at 0.480 V and 0.820 mV (vs RHE), related to the first redox transition of aniline oligomers from leucomeraldine to emeraldine and to the transition from emeraldine to pernigraniline, respectively. A fast electron transfer constant of 9.1 s− 1 for the redox reaction from leucomeraldine to emeraldine is obtained from the dependence of the peak potential on the voltammetric sweep rate. Finally, it was found that the electropolymerization of aniline is a surface sensitive reaction on basal plane platinum electrodes.

► Aniline polymerization on platinum is a structure-sensitive process. ► Ultrathin molecular layers of aniline oligomers have been grown on Pt(111). ► Rate constant for the leucomeraldine base to emeraldine salt conversion is 9.1 s− 1. ► The process between emeraldine and pernigraniline is even faster.