Understanding chemical processes, such as catalysis, at the atomic level is a complex endeavour. It requires a thorough experimental design, which spans from choosing and developing the right model, to using the best instrument to perform controlled and advanced analysis. The latter aspect is where MAX IV comes into play with its state-of-the-art beamlines.
In an article recently published in The Journal of Physical Chemistry Letters, a team of researchers from the Royal Institute of Technology in Stockholm, Stockholm University, and Koç University in Istanbul, presented their work on a single-atom catalyst (SAC) model, with data obtained at the HIPPIE beamline at MAX IV. At HIPPIE, the authors performed Ambient Pressure X-ray Photon Spectroscopy (APXPS) experiments to analyse the catalytic reaction at the atomic level.
To facilitate the understanding of catalysis at the atomic scale, the team created a model based on single crystals of Cu2O(100) (copper oxide) on which they deposited single atoms of Fe, here used as the single-atom catalyst (SAC). The researchers obtained a well-ordered model system with high-density Fe1O3 motifs on single copper oxide crystals. At HIPPIE they performed experiments using APXPS under conditions relevant for CO oxidation. With this setup, they were able to thoroughly observe the chemical state of the isolated Fe1O3 centers at the desired reaction conditions.
“This is one of the first single site model systems that has been studied on single crystals,” said Jonas Weissenreider from the Royal Institute of Technology in Stockholm, and one of the authors of the paper. APXPS experiments performed at HIPPIE were “critical” for the analysis of the active site of the catalyst, and achieving the results presented in this work.
High-Density Isolated Fe1O3 Sites on a Single-Crystal Cu2O(100) Surface
Chunlei Wang, Heloise Tissot, Joakim Halldin Stenlid, Sarp Kaya, and Jonas Weissenrieder
The Journal of Physical Chemistry Letters 2019 10 (23), 7318-7323