Platinum single sites are highly attractive due to their high atom economy and can be generated on CeO2 by an oxidative high-temperature treatment. However, their location and activity are strongly debated. Furthermore, reaction-driven structural dynamics have not been addressed so far. In this study, we were able to evidence platinum-induced CeO2 surface restructuring, locate platinum single sites on CeO2 and track the variation of the active state under reaction conditions using a complementary approach of density functional theory calculations, in situ infrared spectroscopy, operando high-energy-resolution fluorescence detected X-ray absorption spectroscopy and catalytic CO (as well as C3H6 and CH4) oxidation. We found that the onset of CO oxidation is linked to the migration of platinum single sites from four-fold hollow sites to form small clusters containing a few platinum atoms. This demonstrates that operando studies on single sites are essential to assess their fate and the resulting catalytic properties.
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F.M. (ITCP, KIT) thanks the “Fonds der Chemischen Industrie” (FCI) for financial support. J.J. and F.S. acknowledge support by the state of Baden-Württemberg through bwHPC (bwunicluster and JUSTUS, RV bw16G001 and bwl17D011). J.W. is grateful for a PhD fellowship, donated by the China Scholarship Council (CSC). The authors further thank the German Federal Ministry for Economic Affairs and Energy (BMWi: 19U15014B) and the French National Research Agency (ANR‐14‐CE22‐0011‐02) for financial support of the ORCA project within the DEUFRAKO program, the DFG for financial support (INST 121384/16-1, INST 121384/73-1, INST 121384/73-1) and DESY and ESRF for beamtime at the P65 and BM16 beamlines, respectively. We thank D. Zengel, P. Lott, G. Cavusoglu and D. Doronkin (ITCP/IKFT, KIT) for assistance during operando XAS and HERFD-XANES experiments. Furthermore, we acknowledge M. Stehle, A. Deutsch and J. Pesek (ITCP, KIT) for technical support with respect to catalyst preparation, characterization and testing as well as T. Bergfeldt (IAM-AWP, KIT) and H. Störmer (LEM, KIT) for ICP-OES analysis and HAADF-STEM, respectively. Finally, M. Rovezzi, A. Aguilar (BM16, ESRF), E. Welter, R. Nemausat and M. Herrmann (P65, DESY) are thanked for support during beamtime at the corresponding beamlines. We also thank A. Zitolo (Samba, SOLEIL) for fruitful discussion on XANES data calculations.
The authors declare no competing interests.
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Maurer, F., Jelic, J., Wang, J. et al. Tracking the formation, fate and consequence for catalytic activity of Pt single sites on CeO2. Nat Catal 3, 824–833 (2020). https://doi.org/10.1038/s41929-020-00508-7
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