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Van Marum Colloquium: Developing New Paradigms for Applied Catalytic Surface Science

Monday 12 September 2022


Catalytic surface science was developed as a method of “simplifying” the problem of heterogenous catalysis by determining kinetics and mechanisms on compositionally well-defined single-crystal metal surfaces.1 While fundamental studies are vital to our understanding of catalytic processes, transferring this knowledge to “real-world” catalytic systems is extremely difficult. In an attempt to bridge this gap, we are developing instrumentation and methodologies that are able to probe kinetic and mechanistic information at the same resolution as classic surface science while using “real-world” catalytic materials.

We have developed a number of home-built transient packed bed reactors in order to study “real-world” catalytic materials/systems. Using CO oxidation over a Pd catalyst as a test reaction we are able to recreate complex catalytic behaviour witnessed in a UHV molecular beam system2 in a packed bed reactor at 108 times higher pressure (Figure 1). Further, we are able to use time-resolved simulations of our transient experiments to demonstrate continuity between the kinetics coefficients measured using molecular beams2 and those measured on our materials under “real-world” conditions.

Figure 1. A) A CO oxidation molecular beam experiment performed on Pd/Al2O3 model system in UHV. An O2 beam is fired at the catalyst surface, with a flagged CO beam periodically introduced at varying XCO values.2 B) A replicate “pseudo-molecular beam” experiment performed in a packed bed flow reactor atmospheric pressure. The same general trends are identified across 108 times pressure difference. XCO = (pCO)/(pCO + pO2), ptotal = (pCO + pO2).


  1. Reece, C.; Madix, R. J. Moving from Fundamental Knowledge of Kinetics and Mechanisms on Surfaces to Prediction of Catalyst Performance in Reactors. ACS Catal. 2021, 11 (5), 3048– 3066. https://doi.org/10.1021/acscatal.0c05173.
  2. Libuda, J.; Meusel, I.; Hoffmann, J.; Hartmann, J.; Piccolo, L.; Henry, C. R.; Freund, H.-J. The CO Oxidation Kinetics on Supported Pd Model Catalysts: A Molecular Beam/in Situ Time- Resolved Infrared Reflection Absorption Spectroscopy Study. J. Chem. Phys. 2001, 114 (10), 4669. https://doi.org/10.1063/1.1342240.
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