ELECTROCHEMICAL STUDY OF POLYANILINE FILM ELECTRODES AND THEIR MODIFICATIONS - IMPEDANCE SPECTROSCOPY MEASUREMENTS ON HYDROGEN EVOLUTION REACTION

Polyaniline electrodes modified with platinum microparticles were studied using impedance spectroscopy. A thin porous polyaniline film on glassy carbon served as a matrix for electrochemical incorporation of platinum species. Procedures involving hexachloroplatinic acid were used for preparation of the composite electrodes. Impedance/admittance spectra were analysed. Results obtained on modelling the process of/at the reduced polyaniline film electrode in hydrochloric acid solutions are presented. The polyaniline film was found to hinder electrodeposition of platinum originating from anodic dissolution of a Pt auxiliary electrode. A comparative examination of the hydrogen evolution reaction at glassy carbon, glassy carbon modified by a thin polyaniline film, and these electrodes with incorporated platinum particles was undertaken. Preliminary results obtained in the overpotential region are presented. The composite electrode surface was found to be more homogeneous with respect to the double layer formation than for the H-adsorption process. Kinetics of the hydrogen process is observed to depend strongly on a Pt loading.