Quantitative identical location microscopy of structural changes of ceramic-supported Ir oxygen evolution reaction catalyst Ana Rebeka Kamšek 1 , Anja Lončar 1,3 , Gorazd Koderman Podboršek 1,4 , Marjan Bele 1 , Luka Suhadolnik 5 , Primož Jovanovič 1 , Nejc Hodnik 1,3,4 1 Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia, 2 Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia, 3 University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia, 4 Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia, 5 Department of Nanostructured Materials, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia Facing great ecological challenges, our society needs to develop clean and sustainable energy conversion and storage technologies and transfer that knowledge to common use. One of the promising options are hydrogen technologies with hydrogen production taking place via water electrolysis, but the cost-effectiveness of proton exchange membrane water electrolyzers remains limited due to the electrocatalysts containing scarce and expensive noble metals such as iridium. To lower the amount of those critical metals but retain good catalytic activity and stability, more complex systems such as supported nanoparticles can be synthesized. Such electrocatalysts provide promising results, but bring new challenges with regards to understanding their structure- property relationships, requiring advanced characterization to explain the complicated underlying mechanisms. In this work, we focused on explaining atomically resolved structural changes of a titanium oxynitride-supported nanoparticulate iridium oxygen evolution reaction catalyst. A TEM grid was used as a platform for both the synthesis and characterization of the electrocatalyst, where the characterization encompassed electrochemical protocols induced with a modified floating electrode apparatus in conjunction with identical-location scanning transmission electron microscopy to record atomically resolved snapshots of the structure between individual electrochemical protocols. To quantify the structural changes, we employed image analysis algorithms to reveal surface roughening at the atomic scale as the predominant degradation mechanism during the chosen protocols. Quantifying electrochemically induced structural changes with automated image analysis provided us with a faster and more objective analysis of how the coordination of the outermost atomic columns of differently sized Ir nanoparticles changed as a response to external stimuli. These results help understand the complicated processes in oxygen evolution reaction electrocatalysts with ceramic-supported metallic nanoparticles during their operation 1 . References 1. Koderman Podboršek, G.; Kamšek, A. R.; Lončar, A.; Bele, M.; Suhadolnik, L.; Jovanovič, P.; Hodnik, N. Atomically- Resolved Structural Changes of Ceramic Supported Nanoparticulate Oxygen Evolution Reaction Ir Catalyst. Electrochim Acta 2022 , 426 , 140800. https://doi.org/10.1016/j.electacta.2022.140800.
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