Fig. 1: Schematic illustration of the all-in-one MEA concept and preparation process.

a Conventional MEA (C-MEA) and b all-in-one MEA based on 3D-ordered transport highways. c Synthetic procedure for the all-in-one MEA-S.

a Conventional MEA (C-MEA) and b all-in-one MEA based on 3D-ordered transport highways. c Synthetic procedure for the all-in-one MEA-S.