Extended Data Fig. 2: CO stripping and ORR performance of Pt/C, Pd/C and a series of PdHx@Pt NS catalysts prepared with different Pt precursor molar ratios (5%, 10%, 15%, 25% and 50%).
From: Rational design of high-performance low-loading oxygen reduction catalysts for alkaline fuel cells
a, CO stripping voltammograms of different catalysts in Ar-saturated 1.0 M KOH solution. Since Pt was deposited onto the surface of PdHx NS, the surface coverage increased with higher Pt precursor ratios. Accordingly, the CO stripping peak of PdHx NS initially exhibited a much more positive peak potential than Pt/C, but progressively shifted negatively as the Pt ratio increased. Notably, PdHx@Pt NS showed a peak position matching that of Pt/C, indicating that its surface was nearly fully covered with Pt. b, c, ORR polarization profiles of catalysts during anodic (b) and cathodic (c) scans in O2-saturated 1.0 M KOH solution. Even though PdHx@Pt NS did not significantly enhance the ORR activity (ΔE1/2 = 5 mV compared to PdHx NS) during the anodic scans, an activity improvement of 43 mV was achieved in the cathodic scans, pointing to the superior oxidative stability of PdHx@Pt NS.
