Physics Colloquium

Dr. Zdenek Jakub 
^{Central European Institute of Technology (CEITEC), Brno University of Technology, Czechia}

"Experimental modelling of “single-atom” catalysts: What defines molecular adsorption on single-metal sites?"

Abstract:
“Single-atom” catalysis (SAC) presents a recent frontier in catalysis research, promising to lower our dependence on precious metals and improve the economic viability of carbon-neutral technologies. Countless SACs were reported over the past decade, but rational design remains a challenge because the reactivity of “single atoms” is not easy to predict. The main hurdle is that the reactivity doesn’t depend only on the metal atom used, but crucially also on the exact atomicscale structure of its local environment. This renders many reactivity trends developed on nanoparticle catalysts inapplicable for SACs, and requires us to establish new descriptors that could guide efficient SAC research.

In my talk, I will show how we address this challenge from a surface science perspective. I will briefly outline the methodology, strengths and limitations of the surface science approach and I will demonstrate how it can be used to unravel the fundamental aspects defining molecular adsorption on model SACs. Specific focus will be placed on the interaction the “single-atoms” with the support, and how this can lead to stabilization of molecular adsorbates, specific
reaction mechanisms or model catalyst deactivation.[1–5]

In our latest work, we strip away the support-dependent complexity by preparing the “single-atom” sites on surfaces that are chemically inert.[6] This allows us to mimic the active sites present in SACs based on N-doped carbon, and to assess their “intrinsic” reactivity.[7,8] We analyzed Fe2+ cations in various Fe-N3 and Fe-N4 geometries, and we demonstrate that even electronically identical sites can bind reactants with very different strengths.[8,9] These differences originate from distinct possibilities of structural relaxations, which cannot be predicted by analysis of electronic structure alone. Overall, these systematic studies unravel the fundamental aspects defining SAC reactivity, which is a critical prerequisite to rational SAC design.

[1] Z. Jakub, J. Hulva, M. Meier, R. Bliem, F. Kraushofer, M. Setvin, M. Schmid, U. Diebold, C. Franchini, G. S. Parkinson, “Local Structure and
Coordination Define Adsorption in a Model Ir1/Fe3O4 Single-Atom Catalyst” Angew. Chem. Int. Ed. 2019, 58, 13961–13968.
[2] Z. Jakub, J. Hulva, P. T. P. Ryan, D. A. Duncan, D. J. Payne, R. Bliem, M. Ulreich, P. Hofegger, F. Kraushofer, M. Meier, M. Schmid, U. Diebold, G. S.
Parkinson, “Adsorbate-induced structural evolution changes the mechanism of CO oxidation on a Rh/Fe3O4(001) model catalyst” Nanoscale 2020, 12,
5866–5875.
[3] M. Meier, J. Hulva, Z. Jakub, F. Kraushofer, M. Bobić, R. Bliem, M. Setvin, M. Schmid, U. Diebold, C. Franchini, G. S. Parkinson, “CO oxidation by
Pt2/Fe3O4: Metastable dimer and support configurations facilitate lattice oxygen extraction” Sci. Adv. 2022, 8, 1–9.
[4] C. Wang, P. Sombut, L. Puntscher, Z. Jakub, M. Meier, J. Pavelec, R. Bliem, M. Schmid, U. Diebold, C. Franchini, G. S. Parkinson, “CO-Induced Dimer
Decay Responsible for Gem-Dicarbonyl Formation on a Model Single-Atom Catalyst” Angew. Chem. Int. Ed. 2024, 63, e202317347.
[5] J. Hulva, M. Meier, R. Bliem, Z. Jakub, F. Kraushofer, M. Schmid, U. Diebold, C. Franchini, G. S. Parkinson, “Unraveling CO adsorption on model
single-atom catalysts” Science 2021, 371, 375–379.
[6] Z. Jakub, A. Kurowská, O. Herich, L. Černá, L. Kormoš, A. Shahsavar, P. Procházka, J. Čechal, “Remarkably stable metal–organic frameworks on an
inert substrate: M-TCNQ on graphene (M = Ni, Fe, Mn)” Nanoscale 2022, 14, 9507–9515.
[7] Z. Jakub, A. Shahsavar, J. Planer, D. Hrůza, O. Herich, P. Procházka, J. Čechal, “How the Support Defines Properties of 2D Metal–Organic Frameworks:
Fe-TCNQ on Graphene versus Au(111)” J. Am. Chem. Soc. 2024, 146, 3471–3482.
[8] J. Planer, D. Hrůza, T. Lesovský, A. Jabeen, J. Čechal, Z. Jakub, “Structural flexibility dictates reactivity of single-atom catalysts” arXiv preprint
2603.12424 2026.
[9] Z. Jakub, J. Planer, D. Hrůza, A. Shahsavar, J. Pavelec, J. Čechal, “Identical Fe–N4 Sites with Different Reactivity: Elucidating the Effect of Support
Curvature” ACS Appl. Mater. Interfaces 2025, 17, 10136–10144.

Date: Tuesday, April 28, 2025
Institute of Physics, University of Graz, Universitaetsplatz 5, 8010 Graz

Lecture: 4:15 p.m. Lecture Hall 05.01, ground floor

Host: Giovanni Zamborlini

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