fig3

Figure 3. (A) Preparation of ordered nanosized Nafion arrays. (A) Adapted in part with permission from^[58]. Copyright 2023, American Chemical Society; (B) CLs geometry made of Pt /C; (C) CLs geometry made of Pt catalyst on VACNTs film; (D) Simulated polarization curves and platinum utilization efficiency of random carbon-based and VACNTs-supported catalyst coatings; (B-D) Reprinted in part with permission from^[59]. Copyright 2011, Wiley; (E) Mass power density comparison between fuel cells with Pt-NfnPPy electrodes and conventional Pt/C electrodes; (F) Polarization data of MEAs using Pt-NfnPPy and common Pt/C electrodes, operated at 70 °C with fully humidified H₂/air reactants; (G) Structural diagram of the Pt-NfnPPy electrode; (E-G) Adapted in part with permission from^[68]. Copyright 2022, Springer Nature. (H) SEM images of a CANE-7.5 sample; (I) The corresponding STEM-EDS map; (J and K) Polarization curves at the initial and final testing stages under support AST (J) and catalyst AST (K). (H-K) Reprinted in part with permission from^[69] Copyright 2023, Wiley. MEA: Membrane electrode assembly; E-TEK: a commercial catalyst brand; CL: catalyst layer; VACNT: vertically aligned carbon nanotube; STEM-EDS: scanning transmission electron microscopy - energy dispersive X-ray spectroscopy; SEM: scanning electron microscopy; CANE: coaxial nanowire electrode; PPy: polypyrrole; AST: accelerated stress test.