Single Atom Alloy Catalysis for Selective Transformation of (Multi-) Unsaturated Hydrocarbons: from Single Crystal Alloys to Model Alloy Nanoparticles

• Applicant: Professorin Dr. Swetlana Schauermann
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565361343

Heterogeneous catalysts based on Single Atom Alloys (SAA) play an increasingly significant role in a large number of technically relevant processes. In this systems, hybrid metal nanoparticles are employed, in which catalytically highly active ultra-rare elements, e.g. Pd or Pt, are atomically dispersed in more inert yet normally more selective host such as group 11 metals Cu, Ag or Au. This combination of metals enables high selectivity in otherwise highly challenging reactions as well as economical use of expensive ultra-rare group 8-10 transition metals. The unique geometry of SAAs allows to efficiently decouple the location of the highly active sites required for activation of strong bonds and the binding sites of reaction intermediates. In this way, both facile dissociation of reactants and weak binding of intermediates can be enabled, two key factors for efficient and selective catalysis. With the proposed research we are aiming at the atomistic-level understanding of heterogeneous catalysis occurring at the complex SAA-based interfaces. Despite growing number of fundamental-level studies on single crystalline SAA-catalysts, there is still limited microscopic understanding of this hybrid materials in the nanostructured form and acting under technologically relevant ambient pressure conditions. In the proposed research, we will perform fundamental-level studies on reactivity of SAA-based model catalysts both under ultra-high vacuum (UHV) and near ambient pressure conditions, in which the systematic structural variation of the model catalytically active surfaces will be achieved by employing single crystalline SAAs and SAA-based metallic nanoparticles supported on a well-defined planar oxide support. A unique combination of the state-of-the-art experimental techniques will be employed for the first time on nanostructured model SAA-based catalyst to obtain new atomistic-level insights into the underlying elementary surface processes and structure-reactivity relationships. We will systematically change the chemical and the geometric structure of the SAA-based catalysts, such as the nature and concentration of the active metal in the host, the size of the SAA-nanoparticles, the distribution of the active metal atoms across a nanoparticle etc, to establish detailed correlations between the structural and chemical properties of the SAA-based catalyst and the catalytic performance. Our experimental approach includes a combination of scanning tunneling microscopy for structural characterization of SAA-based catalysts; infrared spectroscopy enabling the chemical identification and in operando monitoring of the surface species evolving during the reaction, both under UHV and ambient pressure conditions, and molecular beam techniques allowing for highly controlled kinetic studies. The outcome of this research holds a great potential for developing new concepts towards rational-based design of SAA-based surfaces with tailor-made catalytic properties.

• DFG Programme: Research Grants