Palladium deposition on activated carbon fibre supports and electrocatalytic activity of the modified electrodes towards the hydrogen evolution reaction

In the present study, the creation of carbon fibre-Pd electrodes after several ion exchange-reduction procedures, is investigated. Ion exchange takes place between the H+ ions of the functional acidic groups of the electrochemically oxidized carbon fibres and the Pd2+ ions and is followed by chemical or electrochemical reduction of Pd2+ to Pd-0. The mixed C-Pd electrode systems are studied by cyclic voltammetry, scanning electron microscopy (SEM) and EDAX spectroscopy. The study is completed by impedance spectroscopic measurements at the potential of hydrogen evolution in H2SO4 solutions. The comparison of the SEM and EDAX micrographs shows that the chemically obtained C-Pd systems have a larger effective surface area. The low values of the charge transfer resistance, especially in the case of the chemical reduction, indicate the strong electrocatalytic properties of the prepared electrodes for the hydrogen evolution reaction. (C) 1997 Elsevier Science Ltd.