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

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• 作者：Ave Sarapuu ; Aarne Kasikov ; Naomi Wong ; Chris A. Lucas ; Gita Sedghi ; Richard J. Nichols ; Kaido Tammeveski
• 关键词：Oxygen reduction ; Electrocatalysis ; Gold support ; Palladium film ; Scanning tunnelling microscopy
• 刊名：Electrochimica Acta
• 出版年：2010
• 出版时间：1 September 2010
• 年：2010
• 卷：55
• 期：22
• 页码：6768-6774
• 全文大小：447 K

文摘

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 HClO₄ and 0.05 M H₂SO₄ solutions using the rotating disk electrode (RDE) method. The surface morphology of Pd overlayers was examined by scanning tunnelling microscopy (STM). O₂ reduction predominantly proceeds through 4e⁻ pathway on all Pd/Au electrodes. The specific activity (SA) of oxygen reduction was lower in H₂SO₄ solution and decreased slightly with decreasing the Pd film thickness. In HClO₄, 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.