The GDEs were prepared by doctor-blade coa�ng an Fe-N-C ink onto a gas diffusion layer (GDL) including a microporous layer (Freudenberg, H23C8, 215.5±6.5 µm). During the doctor-blade coa�ng the temperature of the plate of automated film applicator (Zehntner, ZAA 2300) was at room temperature (23.5±0.5 o C). The composi�on of the ink was 12 wt.% solutes in a water/alcohol mixture, consis�ng of 68 wt.% isopropanol (Supelco, EMSURE, ACS ISO), 17.6 wt.% 1-Propanol, 13.6 wt.% water and <0.8 wt.% Ethanol, where the later three components are from the commercial Nafion solu�on (Fuel Cell Store, D2021, 21±1 wt.% Nafion, 34±2 wt.% water, 44±2 wt.% 1-Propanol, and < 2 wt.% Ethanol). The solute frac�on comprised 41.3 wt.% of TAP 900@Fe material and 58.7 wt.% of Nafion. Due to the high mesopore volume of TAP 900@Fe, a rela�vely high ionomer to Fe-N-C weight ra�o of 1.42:1 was used to ensure u�liza�on of the catalyst layer. A�er 30 min of s�rring and 1 h of sonica�on (100 W VWR Ultrasonic Cleaner USC 500 THD) at T < 30 °C, the ink was constantly s�rring un�l deposi�on. A�er the ink deposi�on onto the GDL, the samples were dried at room temperature (21±2 °C) under atmospheric pressure un�l tes�ng. The catalyst layer loading was 0.86±0.15 mg FeNC cm geo , as determined by weighing the GDE before and a�er Fe-N-C coa�ng. The catalyst layer thickness was 58±4 µm, as measured by a micrometer (Helios Preisser, 0912501).