Operando experiments on model catalysts

Supervisor: Doc. Mgr. Iva Matolínová, Dr.
ConsultantMykhailo Vorokhta, Ph.D.RNDr. Peter Matvija, Ph.D.
Status: Available

Abstract:

Model surfaces represent systems with a very well defined structure and ideally with an atomically defined morphology, which allow to study physico-chemical processes taking place on their surfaces. Model catalysts are generally prepared in the form of epitaxial thin oxide or metal layers on suitable single crystal substrates. Their surfaces can be purposefully structured or transformed at the atomic level. Very often, model catalysts are systems where on the support surface the catalytically active material is dispersed in the form of metal clusters of nanometer size. Supported metal clusters have been of interest to many prestigious scientific laboratories for many years, especially those that contain only a few atoms or are dispersed to single atoms to maximize the use of precious metals by exposing each individual metal atom to reactants.

To establish the correlation between structure and catalytic performance and to understand the mechanism of catalytic reaction at the molecular level, it is essential to know the electronic structure and geometric structure of the catalysts at the surface, in volume, subsurface areas and at the interfaces at atomic level and under reaction conditions. This is very important and challenging task, since the catalyst structure can be complexly changed along with changes in reactant pressures and catalyst temperature, which in turn affects the reaction mechanism.

Within this work we propose to study nanostructures supported by CeO2 in-situ /in operado conditions using a unique combination of two state-of-the-art experimental techniques: high pressure X-ray photoelectron spectroscopy (NAP-XPS) and high pressure scanning probe microscopy (NAP-SPM). The research will focus on Pt, Au and Fe nanoclusters, which will be studied before, after, and also directly during the catalytic reactions of small gas molecules. Four industrially important catalytic reactions – CO oxidation, water gas conversion, methan decomposition and stream reforming reaction will be studied.

This project aims to determine the role of various active sites on cerium oxide supported nanostructures in interaction with small molecules under operando conditions.

Literature:

  1. Operando Research in Heterogeneous Catalysis, J. Frenken, I. Groot (Eds.), Springer International Publishing AG, Leiden, Netherlands, 2017, ISBN: 978-3-319-44439-0.
  2. Surface Analysis by Auger and X-Ray Photoelectron Spectroscopy, D. Briggs, J. T. Grant, IMPublications, Chichester, UK and SurfaceSpectra, Manchester, UK, 2003, ISBN: 1‐901019‐04‐7.
  3. Catalysis by Ceria and Related Materials, A. Trovarelli, Imperial College Press, London, UK, 2002, ISBN: 978-1-86094-299-0.
  4. Introduction to Scanning Tunneling Microscopy, C. J. Chen, 2nd ed. Oxford University Press, 2007, ISBN-13: 9780199211500