Hyperspectral full‐field quick‐EXAFS imaging at the ROCK beamline for monitoring micrometre‐sized heterogeneity of functional materials under process conditions.

Full‐field transmission X‐ray microscopy has been recently implemented at the hard X‐ray ROCK–SOLEIL quick‐EXAFS beamline, adding micrometre spatial resolution to the second time resolution characterizing the beamline. Benefiting from a beam size versatility due to the beamline focusing optics, full‐field hyperspectral XANES imaging has been successfully used at the Fe K‐edge for monitoring the pressure‐induced spin transition of a 150 µm × 150 µm Fe(o‐phen)2(NCS)2 single crystal and the charge of millimetre‐sized LiFePO4 battery electrodes. Hyperspectral imaging over 2000 eV has been reported for the simultaneous monitoring of Fe and Cu speciation changes during activation of a FeCu bimetallic catalyst along a millimetre‐sized catalyst bed. Strategies of data acquisition and post‐data analysis using Jupyter notebooks and multivariate data analysis are presented, and the gain obtained using full‐field hyperspectral quick‐EXAFS imaging for studies of functional materials under process conditions in comparison with macroscopic information obtained by non‐spatially resolved quick‐EXAFS techniques is discussed. [ABSTRACT FROM AUTHOR]