Electrocatalytic activity for hydrogen evolution of polypyrrole films modified with noble metal particles

Polypyrrole (Ppy) films of various thicknesses containing particles of noble metals such as Pt, Ru and Ir were electrosynthesized on the surface of austenitic stainless steel (Ss). Two different approaches were applied: (i) electrodeposition of a polymer film from a solution already containing an anionic metal complex, followed by potentiodynamic or galvanostatic reduction; and (ii) presynthesized Ppy films modified by galvanostatic electrodeposition of noble metals from solutions of the metal complexes. Surface morphology and composition of the resulting layers were studied by means of SEM and XPS. The electrocatalytic activity of the modified electrodes for the hydrogen evolution reaction (her) was tested in 0.05 M H2SO4 by means of potentiodynamic techniques (0.5 mV s−1).