Oxygen Reduction Reaction Performance in Phosphoric Acid of a Catalyst Library for High-Temperature Proton Exchange Membrane Fuel Cell
Abstract
High-temperature proton exchange membrane fuel cells (HT-PEMFCs) are advantageous for heavy-duty vehicles owing to their operating temperature (150-200°C), which facilitates the stacks heat management, hence decreases the system global weight. A HT-PEMFC membrane electrode assembly (MEA) commonly relies on phosphoric acid-doped polybenzimidazole membranes. While H3PO4 is optimal in terms electrolyte and membrane properties in HT-PEMFC, it strongly impacts the activity of Pt-based electrocatalysts. In this work, a wide catalyst library highlights most of the material characteristics that, according to the literature, influence phosphate poisoning mechanisms and possibly mitigate the penalty in oxygen reduction reaction (ORR): carbon support, Pt loading on carbon, Pt nanoparticles size, Pt-alloying effect (strain effect) and nano-particles morphology (octahedron (facets orientation), sponges, carbon cap). By electrochemically characterizing the catalyst library, this work aims to understand their ORR activity decline in 1 M H3PO4 vs 1 M HClO4 electrolytes at room temperature. The electrolyte used is relatively concentrated compared to model study in RDE in which the H3PO4 concentration does not exceed 0.1 M (often in a mix with HClO4). Whatever the electrocatalyst, the electrochemical surface area available in H3PO4 decreases by 20-40% compared to HClO4, while a ca. tenfold decline in ORR specific activity is observed. The results highlight the leading-order parameter influencing the absolute catalyst activity in H3PO4: the adsorbates coverage rate by various phosphates species (θ(HxPO4(3-x)-) and θ(HxPO3(3-x)-)), and a second order parameter: the Pt-O, with O from OH*, binding energy on each catalyst (catalyst material-dependent). Both parameters follow a Butler-Volmer model with Frumkin adsorption/desorption isotherm. The loss rate versus HClO4 suggest that the SA retention in H3PO4 also depends on a third order parameter: interactions between adsorbates at the surface of the catalyst, and in the electrochemical double-layer, described by the Frumkin correction, which is largely affected by operating conditions (electrolyte anions concentration and temperature).
Related
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BibTeX
@article{baudy2026oxygen,
title = {{Oxygen Reduction Reaction Performance in Phosphoric Acid of a Catalyst Library for High-Temperature Proton Exchange Membrane Fuel Cell}},
author = {Axelle Baudy and Marion Scohy and Amaria Oudjdi and Tristan Asset and Camille Roiron and Marian Chatenet and Laetitia Dubau},
journal = {ACS Catalysis},
year = {2026},
month = may,
doi = {10.1021/acscatal.6c00952},
url = {https://univ-grenoble-alpes.hal.science/hal-05766681v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Oxygen Reduction Reaction Performance in Phosphoric Acid of a Catalyst Library for High-Temperature Proton Exchange Membrane Fuel Cell
AU - Axelle Baudy
AU - Marion Scohy
AU - Amaria Oudjdi
AU - Tristan Asset
AU - Camille Roiron
AU - Marian Chatenet
AU - Laetitia Dubau
PY - 2026
DA - 2026/05/26
JO - ACS Catalysis
DO - 10.1021/acscatal.6c00952
UR - https://univ-grenoble-alpes.hal.science/hal-05766681v1
AB - High-temperature proton exchange membrane fuel cells (HT-PEMFCs) are advantageous for heavy-duty vehicles owing to their operating temperature (150-200°C), which facilitates the stacks heat management, hence decreases the system global weight. A HT-PEMFC membrane electrode assembly (MEA) commonly relies on phosphoric acid-doped polybenzimidazole membranes. While H3PO4 is optimal in terms electrolyte and membrane properties in HT-PEMFC, it strongly impacts the activity of Pt-based electrocatalysts. In this work, a wide catalyst library highlights most of the material characteristics that, according to the literature, influence phosphate poisoning mechanisms and possibly mitigate the penalty in oxygen reduction reaction (ORR): carbon support, Pt loading on carbon, Pt nanoparticles size, Pt-alloying effect (strain effect) and nano-particles morphology (octahedron (facets orientation), sponges, carbon cap). By electrochemically characterizing the catalyst library, this work aims to understand their ORR activity decline in 1 M H3PO4 vs 1 M HClO4 electrolytes at room temperature. The electrolyte used is relatively concentrated compared to model study in RDE in which the H3PO4 concentration does not exceed 0.1 M (often in a mix with HClO4). Whatever the electrocatalyst, the electrochemical surface area available in H3PO4 decreases by 20-40% compared to HClO4, while a ca. tenfold decline in ORR specific activity is observed. The results highlight the leading-order parameter influencing the absolute catalyst activity in H3PO4: the adsorbates coverage rate by various phosphates species (θ(HxPO4(3-x)-) and θ(HxPO3(3-x)-)), and a second order parameter: the Pt-O, with O from OH*, binding energy on each catalyst (catalyst material-dependent). Both parameters follow a Butler-Volmer model with Frumkin adsorption/desorption isotherm. The loss rate versus HClO4 suggest that the SA retention in H3PO4 also depends on a third order parameter: interactions between adsorbates at the surface of the catalyst, and in the electrochemical double-layer, described by the Frumkin correction, which is largely affected by operating conditions (electrolyte anions concentration and temperature).
SN - 2155-5435
SN - 2155-5435
ER -