Revealing Structure–Performance Relations in Core-Shell Catalyst-Based PEM Water Electrolyzer Anodes with Low Iridium Loading

Finger S, Hoffmeister D, Ma TC, Fiedler L, Morales AL, Körner A, Roubicek N, Lahn L, Böhmer J, Przybilla T, Spiecker E, Kasian O, Freiberg AT, Mayrhofer KJ, Thiele S, van Pham C, Hutzler A (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Energy & Environmental Materials Wiley

DOI: 10.1002/eem2.70458

Abstract

Reducing iridium loading in proton exchange membrane water electrolyzer anodes is essential to meet cost targets for large-scale green hydrogen production. Here, we report a photodeposition-based synthesis of TiO2@IrO2 core-shell catalysts with iridium contents as low as 10 wt%. The influence of annealing temperature, iridium content, and iridium loading on structural and electrochemical properties is systematically investigated. An annealing temperature of 450 °C provides the best compromise between activity, conductivity, and stability. Remarkably, even at 10 wt% Ir (≈4.5 vol% IrO2), the core-shell architecture maintains high electronic conductivity and mass activity. The low iridium content results in ~18 μm thick catalyst layers at a loading of 0.35 mgIr cm−2, corresponding to a high thickness factor of 52.0 ± 0.8 μm (mgIr cm−2)−1. Two-dimensional, two-phase performance modeling reveals that these thick catalyst layers improve electronic connectivity at low loadings, leading to higher catalyst utilization than a commercial reference. As a result, the core-shell catalyst outperforms the reference in single-cell measurements, achieving 1.77 V at 2 A cm−2 at a low loading of 0.31 mgIr cm−2. During 200 h durability testing, reversible degradation is observed, while irreversible losses remain on par with the reference and the core–shell structure is preserved.

Authors with CRIS profile

Johannes Böhmer Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Thomas Przybilla Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)

Additional Organisation(s)

Nanoanalysis and Electron Microscopy (CENEM) Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM) Graduiertenkolleg 3103/1 - Korrelative Materialmikroskopie: Von nanostrukturierten funktionalen Filmen zu hierarchischen Funktionsmaterialien (CorMic)

Involved external institutions

Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE)

How to cite

APA:

Finger, S., Hoffmeister, D., Ma, T.C., Fiedler, L., Morales, A.L., Körner, A.,... Hutzler, A. (2026). Revealing Structure–Performance Relations in Core-Shell Catalyst-Based PEM Water Electrolyzer Anodes with Low Iridium Loading. Energy & Environmental Materials. https://doi.org/10.1002/eem2.70458

MLA:

Finger, Selina, et al. "Revealing Structure–Performance Relations in Core-Shell Catalyst-Based PEM Water Electrolyzer Anodes with Low Iridium Loading." Energy & Environmental Materials (2026).

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