Oxygen reduction on electrodeposited Pd coatings on glassy carbon

The electrochemical reduction of oxygen on electrodeposited palladium coatings was studied in acid and alkaline solutions using the rotating disc electrode (RDE) method. Glassy carbon (GC) was used as an electrode substrate and Pd was deposited at a constant potential varying the deposition time. The surface morphology of the palladized electrodes was examined by scanning electron microscopy. It was found that in alkaline media the Pd/GC electrodes show a high specific activity towards oxygen reduction and it does not depend on the deposition time. In acidic solution a little dependence on deposition time was in evidence. The oxygen reduction reaction (ORR) on electrodeposited Pd proceeds mainly through a four-electron pathway in both solutions and the reduction mechanism is similar to that on bulk Pd.

► O2 reduction was studied on electrodeposited Pd coatings of various thickness.
► Specific activity of Pd for ORR was determined in acid and alkaline solutions.
► Pd/GC electrodes were highly active in alkaline solution.
► Tafel behaviour of O2 reduction was similar for Pd/GC electrodes and bulk Pd.
► Four-electron reduction of O2 proceeds in both acid and alkaline solution.