Translating insights from experimental analyses with single-crystal electrodes to practically-applicable material development strategies for controlling the Pt/ionomer interface in polymer electrolyte fuel cells

Abstract Ionomers are used in polymer electrolyte fuel cells (PEFCs) catalyst layers to improve proton conduction. Recent analytical studies have clarified that the adsorption of ionomer on surface a Pt deteriorates catalytic activity for oxygen reduction reaction and transport properties near surface. These findings led development new materials, such as mesoporous carbon support highly oxygen-permeable ionomer, which now commercially used. In this review article, we summarize recent Pt/ionomer interface focusing half-cell experiments with single-crystal electrodes. We also present promising approaches mitigating adsorption, well remaining challenges application these PEFCs.