Hydrogen evolution on conducting polymer electrodes in acidic media

Hydrogen evolution reaction (HER) was studied on polyaniline (PAn), polypyrrole (PPy) and on aniline/pyrrole (PAn–PPy) copolymer in acidic solutions. The cathodic Tafel slopes (bc) and exchange current densities (j0) were calculated from Tafel curves obtained in solutions of X M H2SO4 (X = 0.1, 0.2, 0.3, 0.4 and 0.5 M). Activation energies (Ea) were determined. The Ea-values were found to be ca. 26 for PAn, 36.5 for PPy, 40.6 for PAn–PPy and 20.6 kJ mol−1for Pt.