Model Catalysts in Action: Studying the Dynamics of Supported Metal Clusters
From fine chemical synthesis over combustion control to electro- and photocatalytic energy conversion – most chemical reactions rely on catalysts to improve energy and material efficiency. Heterogeneous catalysis, in particular, is key to addressing the grand societal challenges of sustainability and climate neutrality by enabling the efficient conversion of small and abundant, yet stable molecules such as CH₄, CO₂, and H₂O into value-added chemicals and fuels. Catalysts are inherently dynamic systems: active nanoparticles and clusters continuously evolve in structure, charge and oxidation state. The dynamic structural fluxionality, i.e. the continuous isomerization of sub-nm clusters, has even been invoked as a reason for their often particular activity. Capturing these transformations in real time and linking them to performance is essential for rational catalyst design.
The overarching aim of our research is to understand and control the structure–activity relationship in heterogeneous catalysis at the atomic scale. We bridge the gap between model and applied catalysts by studying sub-nm (often size-selected) clusters on single-crystalline oxide supports under close-to-realistic pressures and temperatures, bringing fast scanning tunneling microscopy into near-ambient pressure conditions (NAP-STM) and correlating structural dynamics from video-rate imaging with chemical sensitivity from X-ray photoelectron spectroscopy (NAP-XPS) and low-energy ion scattering (LEIS) to explore how support structure, defects, oxidation state, charge and cluster dynamics influence catalytic processes.
Our group uses several ultra-high vacuum (UHV) setups: a NAP-STM, a low temperature LT-STM with magnetron sputtering cluster source and a variable temperature VT-STM (collaborating closely with the Chair of Physical Chemistry). Turn-over frequencies and reaction mechanisms on the same cluster catalysts are studied with our pulsed reactivity ‘sniffer’ setups. Furthermore, we run the e-conversion NAP-XPS facility.
Funding
- ERC Starting Grant (Project TACCAMA)
- DFG Cluster of Excellence e-conversion
- DFG Collaborative Research Center TrackAct
- Fonds der Chemischen Industrie
- BaCaTeC
Publications
J. Reich, M. Soltanmohammadi, V. Vonk, S. Kaiser, U. Heiz, A. Stierle, F. Esch, B. A. J. Lechner, “Steering Pt cluster dimensionality via the surface oxidation state of CeO2(111) thin films”, ACS Catal. 15, 18360-18382 (2025).
F. Kraushofer, M. Krinninger, M. de la Higuera-Domingo, L. Falling, L. Strauss, S. Kaiser, M. Salehi, G. Anand, V. P. Dieste, M. Blum, B. A. J. Lechner, “Pt particles on a dynamic TiO2 support in near-ambient conditions - disentangling size, pressure, and support effects”, J. Am. Chem. Soc. (2025).
A. Facchin, M. Cautero, L. Gregorat, M. Panighel, S. Kaiser, J. Reich, D. Giuressi, B. A. J. Lechner, G. Cautero, F. Esch, “Deployment of an integrated fast scanning probe microscopy module - control software and performance”, Meas. Sci. Technol. 36, 105412 (2025).
J. Reich, S. Kaiser, A. Bourgund, M. Krinninger, U. Heiz, F. Esch, and B. A. J. Lechner, "Exploring the atomic-scale dynamics of Fe3O4(001) at catalytically relevant temperatures using FastSTM", Surface Science 752, 122634 (2025).
F. Kraushofer, M. Krinninger, S. Kaiser, J. Reich, A. Jarosz, M. Füchsl, G. Anand, F. Esch, B. A. J. Lechner, “The influence of bulk stoichiometry on near-ambient pressure reactivity of bare and Pt-loaded rutile TiO2(110)”, Nanoscale, 16, 17825-17837 (2024).
M. Krinninger, F. Kraushofer, N. B. Refvik, M. Blum, B. A. J. Lechner, “Interface Effects in the Stability of 2D Silica, Silicide, and Silicene on Pt(111) and Rh(111)”, ACS Applied Materials & Interfaces 16, 27481-27489 (2024).
J. Reich, S. Kaiser, U. Heiz, J.‑D. Grunwaldt, M. M. Kappes, F. Esch, B. A. J. Lechner, "A Critical View on the Quantification of Model Catalyst Activity", Top Catal 67, 880 (2024).
M. Krinninger, N. Bock, S. Kaiser, J. Reich, T. Bruhm, F. Haag, F. Allegretti, U. Heiz, K. Köhler, B. A. J. Lechner, F. Esch, “On-surface carbon nitride growth from polymerization of 2,5,8-triazido-s-heptazine”, Chem. Mater. 35, 6762-6770 (2023).
S. Kaiser, J. Plansky, M. Krinninger, A. Shavorskiy, S. Zhu, U. Heiz, F. Esch, and B. A. J. Lechner, "Does Cluster Encapsulation Inhibit Sintering? Stabilization of Size-Selected Pt Clusters on Fe3O4(001) by SMSI", ACS Catal. 13, 6203–6213 (2023).
L. Xu, K. G. Papanikolaou, B. A. J. Lechner, L. Je, G. A. Somorjai, M. Salmeron, M. Mavrikakis, "Formation of active sites on transition metalsthrough reaction-driven migration of surface atoms", Science 380, 70-76 (2023).
K. D. Briegel, F. Riccius, J. Filser, A. Bourgund, R. Spitzenpfeil, M. Panighel, C. Dri, B. A. J. Lechner, F. Esch, "PyfastSPM: A Python package to convert 1D FastSPM data streams into publication quality movies", SoftwareX 21, 101269 (2023).
P. Petzoldt, M. Eder, S. Mackewicz, M. Blum, T. Kratky, S. Günther, M. Tschurl, U. Heiz, B. A. J. Lechner, "Tuning Strong Metal–Support Interaction Kinetics on Pt-Loaded TiO2(110) by Choosing the Pressure: A Combined Ultrahigh Vacuum/Near-Ambient Pressure XPS Study", J. Phys. Chem. C 126, 38, 16127-16139 (2022).
S. Kaiser, F. Maleki, K. Zhang, W. Harbich, U. Heiz, S. Tosoni, B. A. J. Lechner, G. Pacchioni, F. Esch, "Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters", ACS Catal. 11, 9519-9529 (2021).
F. Esch, B. A. J. Lechner, “The Molecular Wagon that Stays on Track”, Science 370, 912 (2020).
A. Böttcher, R. Schwaiger, T. M. Pazdera, D. Exner, J. Hauns, D. Strelnikov, S. Lebedkin, R. Gröger, F. Esch, B. A. J. Lechner, M. M. Kappes, “Nanoscale patterning at the Si/SiO2/graphene interface by focused He+ beam”, Nanotechnology 31, 505302 (2020).
B. Arndt, B. A. J. Lechner, A. Bourgund, E. Grånäs, M. Creutzburg, K. Krausert, J. Hulva, G. S. Parkinson, M. Schmid, V. Vonk, F. Esch, A. Stierle, “Order-disorder phase transition of the subsurface cation vacancy reconstruction on Fe3O4(001)”, Phys. Chem. Chem. Phys. 22, 8336-8343 (2020).
A. Bourgund, B. A. J. Lechner, M. Meier, C. Franchini, G. S. Parkinson, U. Heiz, F. Esch, “Influence of local defects on the dynamics of O-H bond breaking and formation on a magnetite surface”, J. Phys. Chem. C 123, 19742-19747 (2019).
C. Dri, M. Panighel, D. Tiemann, L. L. Patera, G. Troiano, Y. Fukamori, F. Knoller, B. A. J. Lechner, G. Cautero, D. Giuressi, G. Comelli, J. Fraxedas, C. Africh, F. Esch, “The new FAST module: A portable and transparent add-on module for time-resolved investigations with commercial scanning probe microscopes”, Ultramicroscopy, 205, 49-56 (2019).
B. A. J. Lechner, F. Knoller, A. Bourgund, U. Heiz, F. Esch, “A microscopy approach to investigating the energetics of small supported metal clusters”, J. Phys. Chem. C, 122, 22569-22576 (2018).