10.26165/JUELICH-DATA/XSX3GA Speer, Sebastian0000-0002-4323-5745(IET-1 Forschungszentrum Jülich GmbH; IPC RWTH Aachen University)Jovanovic, Sven0000-0002-1227-4936(IET-1 Forschungszentrum Jülich GmbH)Merlen, Alexandre0000-0002-8453-299X(Université de Toulon, MAPIEM, Toulon, France)Bartoli, Francesco0000-0002-0739-1580(IET-1 Forschungszentrum Jülich GmbH)Kiran Kiran0009-0002-6779-7723(IET-1 Forschungszentrum Jülich GmbH)Wolf, Niklas0009-0006-2834-5061(IET-1 Forschungszentrum Jülich GmbH; IPC RWTH Aachen University)Karl, André0000-0003-2289-5987(IET-1 Forschungszentrum Jülich GmbH)Jodat, Eva0009-0004-8214-2981(IET-1 Forschungszentrum Jülich GmbH)Eichel, Rüdiger-A.0000-0002-0013-6325(IET-1 Forschungszentrum Jülich GmbH; IPC RWTH Aachen University; Faculty of Mechanical Engineering RWTH Aachen University) Jülich DATA 2025 Raw Raman and XRD Data for the Publication Publication: "Laser-induced oxidation Raman spectroscopy as an analysis tool for iridium-based oxygen evolution catalysts." DOI: https://doi.org/10.1039/D4CP03592E The study investigates the degradation behavior of iridium-based electrocatalysts used in proton exchange membrane electrolysis (PEMEL), a critical industrial technology for hydrogen production. Optical techniques like Raman spectroscopy are particularly suited for this purpose due to their rapid and efficient analysis capabilities. However, metallic iridium is Raman inactive, posing challenges for direct analysis. This work demonstrates the high oxidation sensitivity of iridium and establishes Laser-Induced Oxidation Raman Spectroscopy (LIORS) as a novel method for qualitative, chemical, and structural analysis of iridium catalysts. LIORS is based on the transformation of iridium based materials to IrO2 via laser irradiation by the Raman excitation laser. The study explores how particle size influences the oxidation sensitivity of iridium powders and evaluates the degradation of iridium electrocatalysts after operation in electrolysis. The findings highlight LIORS as a promising tool for the straightforward screening of iridium electrocatalysts in industrial applications. This dataset contains Raman and XRD measurements conducted to investigate the transformation of iridium-based samples to IrO2 and the potential plasmonic effects influencing Raman signal intensity. The dataset is organized into the following folders (please, change to tree view): Raman measurements: Raman spectra were recorded using a WITec Alpha 300R Raman microscope (Ulm, Germany). Data are stored in the folder raman_power_series. Surface enhancement tests: Measurements of methylene blue on iridium powders were conducted using the same WITec Alpha 300R Raman microscope. Results are contained in the folder surface_enhancement_test. XRD measurements: X-ray diffraction (XRD) experiments were performed using an Empyrean diffractometer (Pananalytical, Almelo, Netherlands). The corresponding diffractograms are stored in the folder mea_xrd. For each dataset, detailed experimental procedures and relevant information are provided in the respective folder's ReadMe file. Speer, Sebastian(IET-1 Forschungszentrum Jülich GmbH; IPC RWTH Aachen University)Jovanovic, Sven(IET-1 Forschungszentrum Jülich GmbH)Karl, André(IET-1 Forschungszentrum Jülich GmbH)Jodat, Eva(IET-1 Forschungszentrum Jülich GmbH)