Fig. 4. Electrocatalytic activity of the ultrathin Pt nanoplates in the ORR, benchmarked against the commercial Pt/C catalyst. (a) CV curves of the catalysts in N2-saturated HClO4 (0.1 M) at a sweep rate of 50 mV s–1. The arrow indicates the positive shift of the OH* adsorption peak on the Pt nanoplates relative to that of the Pt/C. (b) ORR polarization curves of the catalysts in O2-saturated HClO4 (0.1 M) at a sweep rate of 10 mV s–1 and rotation speed of 1600 rpm. The current densities were normalized to the geometric area of the rotating disk electrode (0.196 cm2). (c and d) The corresponding Tafel plots. The specific and mass activities of the catalysts given as kinetic current density (jk) were normalized to the ECSA and Pt mass, respectively. (e) Mass and specific activities of the ultrathin Pt nanoplates at 0.9 V vs. RHE, in comparison with the commercial Pt/C catalyst. (f) Comparison of mass activities of the catalysts at 0.9 V vs. RHE before and after the accelerated durability tests.
