Effect of Nafion content and hydration level on the electrochemical area of a Pt nanocatalyst in the triple-phase boundary

JIMÉNEZ-GARCÍA, JUAN C.; OLMOS-ASAR, JIMENA A.; FRANCESCHINI, ESTEBAN A.; MARISCAL, MARCELO M.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Año: 2021 vol. 23 p. 27543 - 27543

1463-9076

espite the great scientific effort, there are still some aspects of a polymeric membrane-based fuel cell (PEMFC) operation that are difficult to access experimentally. This is the case of the so-called triple-phase boundary (TPB), where the ionomer (commonly Nafion) interacts with the supported nanocatalyst (commonly Pt) and is key to the catalytic activity of the system. In this work, we use molecular dynamics simulations and electrochemical experiments on a Nafion/Pt/C system. We perform a systematic analysis, at an atomistic level, to evaluate the effect of several fundamental factors and their intercorrelation on the electrochemically active area (ECSA) of the catalysts. Our results reveal that at high Nafion contents, the catalyst utilization is affected due to the strong interaction between the sulfonic groups of the ionomer and the surface of the Pt nanoparticles (NPs). On the other hand, when the hydration level of the membrane decreases, the sulfonic groups have a greater occ