Throughout the years, a lot of effort has been devoted to improve the electrochemical activity and stability of Pt-based electrocatalysts for the oxygen reduction reaction (ORR), moving from Pt nanoparticles (NPs, diameter ~ 2 – 3 nm) to complex nanostructured materials (i.e. Pt-based hollow, nanoframes or core@shell nanoparticles ^1–3). Most of these nanostructures remain more efficient when supported onto a support, as this results in an enhanced specific surface area and, thus, an enhanced mass activity. As such, the nature and the intrinsic stability of the carbon support cannot be ignored, in particular in terms of durability. Here, we investigated (i) the activity of Pt NPs on different carbon supports (with various degrees of graphitization, specific surface area and surface treatments) and (ii) their stability during load (15,000 step cycles between E = 0.6 V vs. RHE and E = 1.0 V vs. RHE) or start-stop (1,000 step cycles between E = 1.0 V vs. RHE and E = 1.5 V vs. RHE) protocols. To that goal, a combination of complementary experiments (electrochemistry, transmission electron microscopy and Raman spectroscopy) were used. As an example, Figure 1 shows the evolution of the specific activity for the ORR measured at E = 0.95 V vs. RHE before and after the load-cycle ageing procedure.

(1) Dubau, L.; Asset, T.; Chattot, R.; Bonnaud, C.; Vanpeene, V.; Nelayah, J.; Maillard, F. ACS Catal. 2015, 5, 5333–5341.

(2) Chen, C.; Kang, Y.; Huo, Z.; Zhu, Z.; Huang, W.; Xin, H. L.; Snyder, J. D.; Li, D.; Herron, J. A.; Mavrikakis, M.; Chi, M.; More, K. L.; Li, Y.; Markovic, N. M.; Somorjai, G. A.; Yang, P.; Stamenkovic, V. R.; Samorjai, G. A.; Yang, P.; Stamenkovic, V. R.; Somorjai, G. A.; Yang, P.; Stamenkovic, V. R. Science 2014, 343, 1339–1343.

(3) Oezaslan, M.; Hasché, F.; Strasser, P. J. Phys. Chem. Lett. 2013, 4, 3273–3291.