Electroreduction of oxygen on gold-supported nanostructured palladium films in acid solutions

✍ Scribed by Ave Sarapuu; Aarne Kasikov; Naomi Wong; Chris A. Lucas; Gita Sedghi; Richard J. Nichols; Kaido Tammeveski

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 448 KB
• Volume: 55
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2010.05.092

✦ Synopsis

The electrochemical reduction of oxygen on thin Pd films with a nominal thickness of 0.25-10 nm on polycrystalline Au substrate (Pd/Au) was studied. The Pd films were prepared by electron beam evaporation and oxygen reduction was studied in 0.1 M HClO 4 and 0.05 M H 2 SO 4 solutions using the rotating disk electrode (RDE) method. The surface morphology of Pd overlayers was examined by scanning tunnelling microscopy (STM). O 2 reduction predominantly proceeds through 4e -pathway on all Pd/Au electrodes. The specific activity (SA) of oxygen reduction was lower in H 2 SO 4 solution and decreased slightly with decreasing the Pd film thickness. In HClO 4 , the SA was higher and not significantly dependent on the film thickness. The Tafel slope values close to -60 mV at low current densities and -120 mV at high current densities were found for all electrodes.