NSF-DFG MISSI​​ON: Entschlüsselung der Struktur und Dynamik plasmonischer Katalysatoren durch In situ Röntgen- und elektronenbasierte Methoden

• Antragstellerinnen / Antragsteller: Professor Dr. Christoph Tobias Koch; Professorin Dr. Renske van der Veen
• Fachliche Zuordnung: Physikalische Chemie von Festkörpern und Oberflächen, Materialcharakterisierung
• Förderung: Förderung seit 2024
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 541930824

Catalysis plays a key role in the challenges of modern society, such as energy conversion, environmental remediation, and chemical manufacturing. Plasmonic catalysts based on light-absorbing transition metal nanoparticles are proving to be an exciting addition to the field of chemical catalysis because of their ability to promote a wide range of chemical reactions under mild conditions by using visible light as an activating agent. However, the use of plasmonic catalysts faces a major challenge that is preventing precise understanding, formulation of structure–activity relationships, and accurate theoretical models of plasmonic catalysts. Plasmonic catalysts are defined, designed, and modeled on the basis of their static atomic structures; whereas, in reality, the catalysts can restructure and present a different structure under catalytic conditions. In many cases, the surface structure, composition and/or oxidation state of the plasmonic catalyst may change into the active form or into a passivated form not suitable for catalysis in response to the light excitation and/or reaction conditions. Therefore, the goal of this proposal is to obtain atomic-level information about the structures of plasmonic catalysts under actual operating conditions by real-time imaging on the University of Illinois dynamic environmental transmission electron microscope under light irradiation and reactive gas environments, in-situ X-ray absorption spectroscopy at the BESSY II synchrotron facility, and high-resolution electron energy-loss spectroscopy at the Humboldt University Berlin. The nanostructures we will study will consist of a coinage metal, such as gold, silver, or copper, which impart strong light absorption, and a catalytic metal, such as nickel or ruthenium. CO2 and CO hydrogenation will be employed as model reactions because they are important for CO2 fixation and have been shown to be catalyzed by excited charge carriers generated by plasmonic excitation of the nanoparticle catalysts. Under photocatalytic conditions due to effects of plasmonically excited charge carriers, heating, and reactive environments, the two metals can undergo mixing or separation, leading to changes in the light absorption, surface binding of reactive molecules, and catalytic activity and selectivity. The proposed studies will produce knowledge about the active-state, dynamic structure of the bimetallic plasmonic catalysts under actual operating conditions. This will lead to more reliable structure–activity relationships and predictive theoretical models of plasmonic catalysis. In cases of irreversible restructuring causing catalyst deactivation, atomic-level understanding of how the restructuring occurs can reveal the mode of deactivation and point to mitigation strategies for inhibiting restructuring by tuning of the synthesis protocol.

• DFG-Verfahren: Sachbeihilfen
• Internationaler Bezug: USA
• Partnerorganisation: National Science Foundation (NSF)
• Kooperationspartner: Professor Dr. Prashant K. Jain