Fig. 5: The interactions between the surface of carbon support and ionomer (Nafion).
a–d The spatial distribution of the ionomer, O2 and H2O over carbon surfaces with different ratio of C-S-C:S-Ox (represent KB,S-KB 1:3,S-KB 1:2 and S-KB 1:1) after MD simulations (Capturing the dynamic snapshot of 100 Å from 200 Å modeled in the Z direction). e The interface energy between the ionomer and the carbon surface with different thiophene S content. The calculated \({E}_{{\mathrm{int}}}\) is a negative value, the bigger absolute value indicates a stronger interaction in the system and vice versa. f, g RDFs at different thiophene S content: S (thiophene S) − S (side chain) (f) and S (thiophene S) − C (main chain) (g). h The interaction between the surface of traditional carbon support (top) or carbon support modified with thiophene S (bottom) and sulfonic acid group. i Ionomer tends to accumulate among the catalyst particles due to their strong interaction with Pt. j The attraction of thiophene S on the carrier to the ionomer alleviates the buildup of the ionomer around the Pt-based nanoparticles and promotes a uniform ionomer distribution across the entire catalyst layer. k Too high content of thiophene S leads the attraction of carrier to the ionomer far exceed the interaction of the catalyst particles, which results in more ionomer accumulating on the carbon carrier, but the ionomer around the catalyst nanoparticles is thin, and even the particles are exposed, this prevents sufficient protons required for the reaction to reach the three-phase interface through the ionomer.
