Open Access
Tracking dynamic structural changes in catalysis by rapid 2D‐XANES microscopy
Author(s) -
Alizadehfanaloo Saba,
Garrevoet Jan,
Seyrich Martin,
Murzin Vadim,
Becher Johannes,
Doronkin Dmitry E.,
Sheppard Thomas L.,
Grunwaldt Jan-Dierk,
Schroer Christian G.,
Schropp Andreas
Publication year - 2021
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577521007074
Subject(s) - partial oxidation , xanes , catalysis , methane , tracking (education) , chemical imaging , characterization (materials science) , materials science , chemistry , nanotechnology , computer science , spectroscopy , physics , psychology , pedagogy , biochemistry , organic chemistry , quantum mechanics , artificial intelligence , hyperspectral imaging
Many processes and materials in heterogeneous catalysis undergo dynamic structural changes depending on their chemical environment. Monitoring such dynamic changes can be challenging using conventional spectroscopic characterization tools, due to the high time resolution required. Here, a high‐resolution 2D X‐ray camera operating at 50 Hz full‐frame rate was synchronized with a QEXAFS monochromator, enabling rapid spectro‐microscopic imaging with chemical contrast over individual pixels. This was used to monitor chemical gradients within a model Pt/Al 2 O 3 catalyst during catalytic partial oxidation of methane to synthesis gas. The transition from methane combustion (partly oxidized Pt) to combustion‐reforming and partial oxidation (fully reduced Pt) was observed by a characteristic reduction front, which progressed from the end of the catalyst bed towards its beginning on the second time scale. The full‐field QEXAFS imaging method applied here allows acquisition of entire XANES spectra `on the fly' in a rapid and spatially resolved manner. The combination of high spatial and temporal resolution with spectroscopic data offers new opportunities for observing dynamic processes in catalysts and other functional materials at work. The methodology is flexible and can be applied at beamlines equipped with a QEXAFS or other fast‐scanning monochromators and a suitable sample environment for gas phase analytics to allow for catalytic studies at the same time.