Fig. 4: Physical and electrochemical characteristics of Pt/cPDA based catalyst layers.

a STEM-EDX mapping of Pt/cPDA CL showing the ionomer and Pt distribution, b Effect of RH on ECSA (H_ad) and C_DL of Pt/cPDA CL, c Mass activity Tafel plot comparison between Pt/cPDA and TKK Pt/C catalyst in MEA condition^* (d) i_m,0.9V comparison in both RDE and MEA condition between Pt/cPDA^* and different Pt catalysts reported in literature^{16,17,31,36,48} (all the reported RDE activity values in (d) were performed in the ionomer-free system except Pt/HSC and GBP-Pt-600), e comparison of pressure independent O₂ transport resistance between Pt/cPDA and other Pt-based catalysts reported in the literature^8,9,16,17,36 (values inside the bracket indicate Pt loadings in mg_Pt cm⁻²), ^*Pt/cPDA MEA condition: 70 °C, 100% RH (80% RH for O₂ transport resistance), 140 kPa_abs, H₂/O₂ for activity measurements. E was corrected for iR-losses, and current density was corrected by adding crossover current to the measured current. Literature data recorded at 80 °C, 100% RH, 150 kPa_abs, H₂/O₂, ^ai_m,0.9V was assumed to be 150 kPa_abs; operating pressure was not mentioned; ^b i_m,0.9V measured at 300 kPa_abs, recalculated at 150 kPa_abs following the method explained in ref. 49. The error bar in b–d are deviation from the average of data from three individual testings, except for the mass transport resistance (e), which was repeated twice.