화학공학소재연구정보센터
Journal of Electroanalytical Chemistry, Vol.624, No.1-2, 144-150, 2008
Electroreduction of oxygen on gold-supported thin Pt films in acid solutions
The electrochemical reduction of oxygen was studied on vacuum evaporated thin Pt films (0.25-20 nm thick) on polycrystalline Au substrate (Pt/Au) 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 Pt films was examined by scanning tunnelling microscopy (STM). The O(2) reduction specific activity of Pt films increased with increasing the film thickness in HClO(4), but was lower than that of bulk Pt even for the thickest films. In H(2)SO(4), the specific activity showed no significant dependence on the platinum loading and was lower than in HClO(4). The Tafel slope values characteristic to polycrystalline Pt (-120 mV dec(-1) and -60 mV dec(-1)) were found for all electrodes. The RRDE studies of 0.5 nm Pt/Au electrode revealed that O(2) reduction predominantly proceeds through 4e(-) pathway and H(2)O(2) is produced in low quantities. (C) 2008 Elsevier B.V. All rights reserved.