Advanced Operando X‐Ray Absorption Spectroscopy for Catalysis at High Temperature and Pressure: Insights from the French Absorption Spectroscopy Beamline in Material and Environmental Sciences and French Absorption Spectroscopy Beamline in Material and Environmental Sciences at Ultra‐High Dilution Beamlines at European Synchroton Radiation Facility

Operando X‐ray absorption spectroscopy (XAS) has undergone a transformation thanks to advances in synchrotron instrumentation and reactor‐cell design, enabling studies of heterogeneous catalysts under working conditions. This topical review surveys these developments and shows how they are implemented on the BM30 (FAME‐PIX) and BM16 (FAME‐UHD) beamlines at the European Synchrotron Radiation Facility (ESRF). Both beamlines now combine high‐flux optics with catalysis‐oriented detection, including a 16‐element Mirion HPGe solid‐state detector (SSD) for sensitive XAS of active sites and a 14‐crystal analyzer spectrometer for high‐energy‐resolution fluorescence detection (HERFD) and X‐ray emission spectroscopy (XES) to track changes in oxidation state and local structure. They also include operando reactor cells capable of operating at temperatures up to 1000°C and pressures up to 100 bar, matching industrial catalytic conditions. We describe the beamline configurations, sample environments and detection modalities, and discuss how their combined use enables real‐time structural and electronic characterization of catalysts. Case studies on methane reforming, ethane dehydrogenation, CO 2 hydrogenation and methane dehydroaromatization demonstrate the scientific impact and versatility of these setups. Collectively, BM30 and BM16 are key tools for operando XAS and help bridge the gap between fundamental understanding and industrial catalytic processes.