Highlights ORR-kinetics study on Pt and Ag by using thin-layer catalysts in a AEMFC at 80 °C. Ag shows a later onset potential for ORR and lower performance at high voltages. The Tafel slope of Pt is 75 mV dec−1 above 0.8 V, for Ag the slope is 160 mV dec−1. For Ag, a voltammetric anodic peak at 0.8 V, indicates formation of Ag2O. Ag performs better than Pt below 0.5 V, but its stability is affected above 0.8 V.