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. 2022 Nov 2;8(44):eadd8873. doi: 10.1126/sciadv.add8873

Fig. 1. Electrochemical molecular probe method to identify efficient TPB region.

Fig. 1.

(A) A schematic of electrochemical molecular probe method with different-sized organics as probe molecules to determine the ORR contribution from different pore size ranges. (B) The controlled coverage area of the PDA-Ar catalyst by seven different-sized organics for the fuel cell activity test. (C) Polarization curves (iR-free) of H2-O2 PEMFC using the PDA-Ar Fe/N/C as the cathode catalyst with and without the addition of organics. Test conditions are composed of the following: 80°C (cell temperature), 1-bar backpressure, 0.3 SLPM with 100% RH for H2 and O2, Nafion 212 membrane, Fe/N/C catalyst with 4.0 mg cm−2 (cathode), and Pt/C (40 wt %; JM) with 0.4 mgpt cm−2 (anode). (D) Relative current density at 0.8 ViR-free of the PDA-Ar Fe/N/C cathode after the addition of different-sized organics. (E) ORR activity contribution from different regions.