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Projekt Druckansicht

Ligand-induzierte heterogene Katalyse zur Steuerung der Chemoselektivität von Oberflächenreaktionen mit mehreren Reaktionspfaden: mechanistisches Verständnis mittels des Oberflächenchemie-Ansatzes.

Fachliche Zuordnung Physikalische Chemie von Festkörpern und Oberflächen, Materialcharakterisierung
Physikalische Chemie von Molekülen, Flüssigkeiten und Grenzflächen, Biophysikalische Chemie
Förderung Förderung von 2018 bis 2022
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 415543392
 
Erstellungsjahr 2022

Zusammenfassung der Projektergebnisse

Summarizing, in this project a broad range of intermolecular interactions was addressed by a unique combination of state-of-the-art experimental methods including IRAS, STM, molecular beam techniques, which were combined with theoretical calculations carried out in collaboration with Prof. Bernd Hartke (CAU Kiel). The specific focus of this research was at the atomistic-level understanding of intermolecular interactions at the model gas/sold interfaces mimicking the surface of heterogeneous catalysts functionalized with organic ligands. We reported a number of successful examples, in which the origin and the effect of the intermolecular interactions on the surface chemistry was understood in great details. Specifically, the mutual interaction of carbonyl compound acetophenone were shown to result in formation and stabilization of enol species, which can undergo low-temperature hydrogenation pathway of the carbonyl bond. We show that by choosing specific reaction conditions and the chemical environment of the carbonyl group, we can achieve stabilization of more than one enol species per one carbonyl entity, which opens up a prospect of rational design of functionalized catalytic surfaces for low-temperature hydrogenation of carbonyl compounds. Mutual interactions between ester molecules (ethyl pyruvate) were shown to result in a strong weakening of the C-O ester bonds, potentially making them more prone to chemical transformations. Formation and dynamic changes of self-organized ligand layers were extensvely investigated for a number of molecular species, including R-NEA, allyl cyanide and others. Specifically for allyl cyanide, we have shown that the chemical nature of the initially adsorbed molecules strongly changes under the operando reaction conditions, resulting in appearance of an active ligand layer with a specific well-ordered structure. This layer turns the surface highly active and nearly 100% selective toward hydrogenation of the C=O bond in acrolein to unsaturated alcohol. Currently, further ligands are being investigated to address the fundamental understanding of the structure-reactivity relationships of ligand-induced catalysis or a broader range of ligand compounds. During the funding period of this project we also initiated the studies on metal nanoparticles supported on well-defined oxide layers. Due to Covid19 pandemic and noticeable shortage in the working time in the lab as well as health situation of involved PhD students, these studies were delayed and could be carried out only starting from the beginning of 2022. Up to now, we achieved some promising results in this part of the project and will continue the investigations on ligand-functionalized nanoparticles in the future. Two further papers are being now in preparation, which treat both the results obtained of ligand-functionalized single crystal surfaces as well as on supported Pd nanoparticles. In total, we believe to have achieved very deep atomistic-level of understanding of mutual adsorbate-adsorbate interactions relevant for ligand-induced catalysis as well as to have deduced the mechanisms of underlying surface processes and structure-reactivity relationships. We hope to be able to further advance this field in our currently performed investigation.

Projektbezogene Publikationen (Auswahl)

 
 

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