Publication date: 17th July 2025
The energy transition stands as one of the greatest challenges of today’s society. In this context, electrocatalyst materials at the heart of electrochemical energy conversion devices such as fuel cells and water electrolyzers are expected to play an increasing crucial role in the near future. The urgent bottleneck to be overcome in electrocatalyst materials development to allow the widespread deployment of electrochemical systems is thus reaching combined high activity and long-term stability at low cost. Despite the diversity in electrocatalyst materials, the latter being largely imposed by the various types of electrochemical systems (noble vs. non-noble metals in acidic vs. alkaline media for example) and the prerequisites of the different electrochemical processes (oxidation or reduction reactions of various species at different electrode potential ranges), most activity and stability properties of electrocatalysts directly derive from their (surface) chemistry and structure. Such properties (and their temporal evolution) can thus be directly investigated by means of in situ or operando high energy X-ray scattering (XRD) technique.
In this presentation, the versatility of in situ and operando XRD technique in addressing key bottlenecks in electrocatalyst materials development, notably by probing adsorption and oxidation trends, will be showcased. Finally, the ability of operando XRD to provide device-relevant insights at the macroscale beyond electrocatalysts microstructural properties (such as ionomer hydration in PEMFCs or water distribution in AEMFCs) will be presented [1-4].
R.C gratefully acknowledge financial support from the French National Research Agency through the HOLYCAT project (grant number n◦ ANR-22-CE05-0007) and PEMFC95 funded by “France 2030" operated by the French National Research Agency (grant ANR-22-PEHY-0005).