Extended Data Fig. 6: ORR catalytic performance data.
From: Zirconium nitride catalysts surpass platinum for oxygen reduction
RDE polarization curves of (a) Pt/C, (b) ZrN NPs, (c) ZrO2 NPs and (d) Zr2ON2 NPs in O2-saturated 0.1 M KOH at rotation speeds ranging from 400 to 2025 rpm and a scan rate of 10 mV s−1. Koutecky–Levich plots of (e) Pt/C, (f) ZrN NPs, (g) ZrO2 NPs and (h) Zr2ON2 NPs at potentials from 0.4 to 0.6 V. The kinetic current is calculated from the ORR polarization curves by using the Koutecky–Levich equation (1/i =1/ik + 1/id, where ik is the kinetic current, and id is the diffusion-limiting current), which gives linear plots of the inverse of current density (j−1) against the inverse square root of rotation speed (ω−1/2) as shown.
