The oxygen reduction reaction (ORR) on a Pt/C-based thin catalyst layer is studied using the rotating ring-disk electrode (RRDE) technique in an O-2-saturated acid solution. A modified model for obtaining the ORR constants in different electrode potential ranges is validated using the experimental disk and ring currents. The results calculated from the model and the Koutecky-Levich plots reveal that the ORR constants on three different Pt surfaces (Pt-H, Pt, and PtOX/Pt) are significantly different, among which, pure Pt surface is found to have the best activity towards ORR. This model can also give a detailed formularization of the apparent ORR electron transfer number (n) and the percentage of H2O2 (%H2O2) produced during the ORR process. (C) 2014 Elsevier B.V. All rights reserved.