IN-SITU EXAFS-ELECTROCHEMICAL STUDY OF REDUCTION OF MOLECULAR-OXYGEN ON MO-RU-SE THIN-LAYERS ELECTRODES IN ACIDIC MEDIA

The structure of transition metal selenide compounds (Mo-Ru-Se) in thi n layer form, and its change under exposure to the electrolyte and ele ctric potential was investigated by in situ EXAFS and electrochemical measurements. The composition appeared to be a mixture of Mo-Se and Ru -Se phases. A dissolution of the molybdenum species and, the formation of ruthenum (hydro)oxide compounds was revealed by the EXAFS data ana lysis. The ruthenium (hydro)oxide seems to be the species responsible for the catalytically active center during th electroreduction of mole cular oxygen.