Protocol for the ex-situ electrochemical performance evaluation of the high-temperature pemfc electrodesMaurya, Rajan Ma (Avtor) Morgen, Per (Avtor) Gyergyek, Sašo (Avtor) Andersen, Shuang Ma (Avtor) electrocatalystsaccelerated stress testEffect of pre-wetting on catalyst utilization and durability of high-temperature proton exchange membrane fuel cell (HT-PEMFC) gas diffusion electrodes (GDEs) was investigated in a three-electrode configuration. Pre-wetting protocols included treatment in ethanol-water mixture (0, 10, 50 and 100 % v/v ethanol), ethanol-water vapor and concentrated orthophosphoric acid (14.85 M) at 150 °C. All pre-wetting approaches significantly enhanced electrode wettability by reducing hydrophobicity and surface tension, leading to improved initial catalyst utilization. However, accelerated stress test (AST) revealed a trade-off between utilization and durability, with wetted electrodes exhibiting lower electrochemically active surface area (ECSA) and Pt retention compared to untreated electrodes. Changes in Pt crystallite and particle sizes during the AST were estimated through X-ray diffraction analysis and transmission electron microscopy. All three wetting procedures have similar effects on catalyst utilization and durability without compromising the structural integrity. Single-cell measurements showed that while pre-wetting is effective for rapid screening and improving the initial performance, its benefits are not directly transferable to practical operation without further optimization. These findings highlight the trade-off between catalyst utilization and durability in HT-PEMFC GDEs.Published on behalf of The Electrochemical Society by IOP Publishing Limited. 20262026-06-16 08:57:21Neznano30140UDK: 544.5/.6ISSN pri članku: 1945-7111DOI: 10.1149/1945-7111/ae747aCOBISS_ID: 280065283sl© 2026 The Author(s).