Rational design of better catalysts requires precise knowledge about the structure of active sites and their reactivity during catalytic cycle. However, for majority of catalytic systems and processes such information remains elusive due to large structural heterogeneity of catalytic material and various limitations of experimental and theoretical methods. Here, element specific operando spectroscopy helped us to gain such knowledge for copper-ceria system, which finds application in exhaust and sustainable energy catalysts. For this study, we have chosen the material with well-defined structure consisting of finely dispersed copper-oxo species (predominantly dimers) stabilized on ceria surface. Using times-resolved X-ray absorption spectroscopy we observed that oxidation states of copper and cerium atoms forming active sites change in concert allowing efficient catalytic oxidation of carbon monoxide below 100 oC. The developed methodology can be applied in future for more complex catalytic systems and processes to clarify complex structure-activity relationships.
Contact
Dr Olga Safonova
SuperXAS beamline
Operando spectroscopy group & Laboratory for Synchrotron Radiation and Femtochemistry (LSF)
Swiss Light Source, Paul Scherrer Intitute
5232 Villigen-PSI, Switzerland
Telephone: +41 56 310 58 05
E-mail: olga.safonova@psi.ch
Original Publication
Elucidating the Oxygen Activation Mechanism on Ceria-Supported Copper-Oxo Species Using Time-Resolved X-ray Absorption Spectroscopy
Olga V. Safonova, Alexander Guda, Yury Rusalev, René Kopelent, Grigory Smolentsev, Wey Yang Teoh, Jeroen A. van Bokhoven, Maarten Nachtegaal
ACS Catalysis, 25 March 2020
DOI: 10.1021/acscatal.0c00551