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Figure 4. (A) Sketch of oxygen delivery paths from flow channels to CLs. (A) Reprinted in part with permission from[87]. Copyright 2024, Elsevier; (B) Model diagrams of ionomer-carbon-platinum interactions. (B) Reprinted in part with permission from[92]. Copyright 2024, Springer Nature; (C) Schematic of carbon pore geometry impacts on platinum catalytic performance. (C) Reprinted in part with permission from[93]. Copyright 2010, Elsevier; (D) Schematic diagram of ordered macro-mesoporous Pt/C. (E) Chronopotential curves measured in O2-saturated 0.1 M HClO4 at 2 mA cm-2. (D and E) Reprinted in part with permission from[101] Copyright 2018, Wiley; (F and G) 2D multiphysics simulation results of planar and channeled electrodes: (F) ORR current contour at 0.7 V; (G) normalized oxygen concentration field at 1.0 A cm-2, arrows represent O2 diffusion routes. (F and G) Adapted in part with permission from[102]. Copyright 2023, Springer Nature; (H) Diagram of dual-sided structured MEA configuration, plus operation principles of standard and ordered MEAs. (H) Reprinted in part with permission from[103]. Copyright 2024, Royal Society of Chemistry; (I) Illustration of CLs with horizontal through-pores and lateral reactant transport inside these planar channels; (J) I-V polarization curves and power density curves for FCL, PA-PCL, and PE-PCL at 100% RH (error bars indicate a voltage fluctuation during galvanostatic measurements at each current density); (K) Total O2 transport resistances. (I-K) Reprinted in part with permission from[105]. Copyright 2018, American Chemical Society. GDL: Gas diffusion layer; CL: catalyst layer; PEM: proton exchange membrane; NP: nanoparticle; HOMC: hollow ordered mesoporous carbon; RHE: reversible hydrogen electrode; CMK: carbon mesostructured from KAIST; WMC: wormhole-like mesoporous carbon; DL: diffusion layer; MPL: microporous layer; FCL: flat catalyst layer.
