Perturbation-enhanced Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS) combined with Temporal Analysis of Products (TAP)
Heterogeneous catalysts work by binding the reagent molecules to specific active sites on their surfaces and subsequently converting reagents into products with minimal energy costs. Newly formed product molecules subsequently detach from the catalyst, thereby freeing up the active sites for the next conversion cycle. However, catalytic surfaces are not static and may drastically transform when brought into contact with reagents and products. Recent progress in the science of catalysis has revealed that the most active and selective catalytic sites can, in fact, be formed as a result of these transformations. For example, catalytic metal nanoclusters can change their oxidation state and form unique active sites at their interface with an underlying metal oxide support. In this project, we are investigating exactly how the interactions between catalysts and reactive molecules lead to new atomic arrangements on catalytic surfaces with improved performance.
We are combining two very different, but complementary cutting-edge techniques to gain a deeper understanding of how different components of complex catalytic materials synergistically interact and evolve under reaction conditions. Both techniques rely on time-resolved measurements. Temporal Analysis of Products (TAP) is employed to precisely measure the rates of gas-surface reactions and catalytic selectivities. Ambient Pressure X-Ray Photoelectron Spectroscopy (AP-XPS) is used to probe the chemical state of catalytic surfaces at the atomic scale using synchrotron-generated light. In addition, in situ Raman and IR spectroscopies are utilized for complimentary materials characterization and mechanistic studies. These tandem spectro-kinetic data will illuminate molecular-scale details that underpin structure-performance relationships for model and technologically-relevant complex oxide surfaces. In order to enable this synergistic approach, we are preparing innovative metal-oxide materials with equivalent microstructures on 2D and 3D substrates via controlled decomposition of Metal-Organic Framework (MOF) films.
People: Unni Olsbye (UiO), Evgeniy Redekop (UiO), Maria Evangelou Kalyva (UiO), Niclas Johansson (MAX IV), Samuli Urpelainen (MAX IV), Spyros Diplas (SINTEF), Joachim Schandt (Lund University/MAX IV), Karl Petter Lillerud (UiO), Francisco Javier Narciso Romero (UiO, Universidad de Alicante).
January, 2019 cutting edge synchrotron experiments by team TAPXPS are highlighted on MAX-IV website
29-31 January, 2019 team TAPXPS will present two posters and a talk at the Operando Surface Catalysis (OPSCAT) conference in Oslo, Norway. Stay tuned!
16-17 October, 2018 the TAPXPS team will present their work at the Norwegian National Chemistry Meeting in Lillestrøm, Norway.
13-15 June, 2018 UiO will host an InterReg workshop "Time, Work, Function" (TWF-2018) where the state-of-the-art in time-resolved X-Ray and neutron methods will be discussed.
Maria Kalyva, Martin F. Sunding, Annette E. Gunnæs, Spyros Diplas, and Evgeniy A. Redekop, Correlation between surface chemistry and morphology of PtCu and Ptnanoparticles during oxidation-reduction cycle, Appl. Surf. Sci. 532 (2020) 147369, DOI: 10.1016/j.apsusc.2020.147369
more to come...
Funding: Norwegian Research Council - Nano2021 (previous SYNKNØYT),
The European Development Fund - INTERREG