Thin Films

Thin Films

The activities of the group are centered around thin film catalyst models. Such models mimic relevant aspects of a real world catalysts, but have a reduced complexity. That allows us to understand catalytic processes in detail. Central activities of the group are the development of thin film preparation recipes and the study of thermal and electrocatalytic reactions at the thin film / gas or liquid interfaces.

Supported catalysts may be mimicked by deposition of metallic aggregates. Several surface-sensitive experimental methods (XPS, TPD, STEM, EELS, IR surface action spectroscopy) are applied under vacuum conditions and at elevated pressures.

Group Members

Dr. Earl Davis
Dr. Ane Etxebarria
Dr. Afshan Jamshaid
Dr. David Koshy
Walter Wachsmann 

Research

SPM

SPM

Scanning probe microscopy is applied to investigate surface structures. Sometimes also X-ray based structural methods or I/V-LEED structural analysis may be used.

XPS

XPS

With XPS the elemental composition of the surface and the electronic structure of the surface atoms is investigated. This may also involve adsorbates and/or deposited aggregates.

HREELS

HREELS

HREELS is a method for the study of vibrations and electronic excitations at the surface. It may also reveal relevant information about deposited aggregates and adsorbates. In this method electrons are scattered inelastically at a surface. Hereby the electrons suffer an energy loss which is the desired information.

Action Spectroscopy

Action Spectroscopy

Surface action spectroscopy is a newly developed vibrational method. The investigated surface is covered with weakly bound atoms (the messengers) which are desorbed when infrared radiation [coming from the free electron laser (FEL) of the Institute] excites a vibration of the surface.

Recent Publications

Yun Liu, Zhongkang Han, Sandy Gewinner, Wieland Schöllkopf, Sergey V. Levchenko, Helmut Kuhlenbeck, and Beatriz Roldan Cuenya, "Adatom Bonding Sites in a Nickel-Fe3O4(001) Single-Atom Model Catalyst and O2 Reactivity Unveiled by Surface Action Spectroscopy with Infrared Free-Electron Laser Light," Angewandte Chemie International Edition 61 (28), e202202561 (2022).
Joachim Paier, Connie J. Nellin, Paul S. Bagus, Agata Plucienik, Helmut Kuhlenbeck, and Hans-Joachim Freund, "Electronic structure of reduced CeO2(111) surfaces interacting with hydrogen as revealed through electron energy loss spectroscopy in comparison with theoretical investigations," Journal of Electron Spectroscopy and Related Phenomena 257, 147088 (2022).
Nina F. Richter, Hendrik Ronneburg, Peter M. Clawin, Noah Subat, Felix E. Feiten, Jagriti Pal, Emre Emmez, Shamil K. Shaikhutdinov, Helmut Kuhlenbeck, Thomas Risse, and Hans-Joachim Freund, "Electron-Stimulated Hydroxylation of Silica Bilayer Films Grown on Ru(0001): A Combined HREELS and EPR Study," The Journal of Physical Chemistry C 126 (18), 7956-7964 (2022).
Yun Liu, Helmut Kuhlenbeck, and Hans-Joachim Freund, "Eine neue Methode zur Messung von Schwingungen an Festkörperoberflächen: Surface Action Spectroscopy," Bunsen-Magazin 23 (6), 276-279 (2021).
Giulia Berti, Earl Davis, Helmut Kuhlenbeck, and Hans-Joachim Freund, "Interaction of CO2 with well-ordered iron sulfide films on Au(111)," Surface Science 710, 121853 (2021).

Talks

Kuhlenbeck, H.: Model Studies of Crystalline Thin Oxide Films: Surface Action Spectroscopy and Electrochemistry. FHI-Workshop on Current Research Topics at the FHI, Potsdam, Germany (2021)

Former Group Photos

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