SFB 1625:  Atomic-scale understanding and design of multifunctional compositionally complex solid solution surfaces

• Subject Area: Chemistry ; Computer Science, Systems and Electrical Engineering ; Materials Science and Engineering ; Mathematics ; Physics ; Thermal Engineering/Process Engineering
• Term: since 2024
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 506711657

Compositionally complex solid solutions (CCSS) comprising five or more different elements mixed in a simple single-phase crystal structure provide conceptually unique, highly promising prospects in important scientific and technological areas, where the surface dominates properties such as – and ultimately not limited to –electrocatalysis and corrosion, crucial for future sustainable energy conversion systems. The CRC aims to leverage the possibilities of CCSS as material design platforms by establishing a combined theoretical and experimental understanding of their atomic-scale surface features, as the unique properties of CCSS are caused by the large number of diverse poly-elemental active sites across their surface. Gaining control of and the ability to design these surface atom arrangements (SAA) has the potential to overcome limitations of conventional electrocatalysts and will pave the way to multifunctional materials, with unprecedented combinations of activity and stability as well as possibilities for cascade reactions. SAA are specific arrangements of (sub)surface atoms and their chemical identities. They form in statistical abundance the surface composition of CCSS. Knowledge of SAA is essential for designing composition-structure‑activity relations for CCSS surfaces. The CRC aims to understand and control SAA – their formation, their variation for different systems and compositions, changes in SAA due to experimental conditions – to systematically tailor and manipulate them to design their properties. Development of new catalysts is not the primary goal; rather, advancement in fundamental understanding and exploration of new opportunities offered by SAA of CCSS. Initially, noble metal thin films will be used as model CCSS as their oxidation resistance supports SAA identification. Gaining detailed insights into the dependence of reaction mechanisms on the SAA and the understanding of CCSS surface metallurgy will then enable the design of multifunctional and sustainable electrocatalysts. This multi-dimensional challenge will be addressed by a fully interdisciplinary team (materials science, surface science, physics, chemistry, data science) using high-throughput methods in atomistic simulation, synthesis, characterisation, electrochemical probing, and in-depth experiments towards atomic-scale resolution. SAA determine electrochemical reactions on the atomic scale which is addressed by theory and atomic-scale characterisation. However, this atomistic view needs to be combined with the high-dimensional composition-property space of SAA and CCSS. Using materials informatics, we will integrate all data across scales and research areas, establish data-guided workflows, extract knowledge from data and organise it in knowledge graphs. Our holistic approach will be used to fulfil the vision of the CRC to control SAA on the atomic scale and across the surface and enable the design of ideal CCSS surfaces for specific applications.

• DFG Programme: Collaborative Research Centres
• International Connection: Denmark

Current projects

• A01 - Theoretical electrochemistry of CCSS surfaces and high-throughput exploration of CCSS thin film systems (Project Heads Ludwig, Alfred ;  Rossmeisl, Jan )
• A02 - Microstructure design of quasi-single-crystalline and smooth model thin films (Project Heads Ludwig, Alfred ;  Raabe, Dierk )
• A03 - Simulation of segregation and ordering at CCSS surfaces (Project Head Drautz, Ralf )
• A04 - Ab initio simulations of electrochemical reactions at CCSS surfaces (Project Head Neugebauer, Jörg )
• A05 - Data-guided experimentation and machine learning (Project Head Stricker, Markus )
• A06 - Establishing a knowledge graph for the design of CCSS (Project Head Acosta, Maribel )
• B01 - Accelerated atomic-scale exploration of phase evolution in CCSS systems using combinatorial processing platforms (Project Heads Kostka, Aleksander ;  Li, Yujiao )
• B02 - Revealing the relations between surface atomistic coordination and electrochemical performance of CCSS towards HER (Project Head Li, Ph.D., Tong )
• B03 - High resolution (scanning) transmission electron microscopy investigation of the surface and other defects in CCSS (Project Heads Scheu, Christina ;  Somsen, Christoph )
• B04 - Enabling (quasi)-in-situ analytical field-ion microscopy of active CCSS catalysts (Project Heads Freysoldt, Christoph ;  Gault, Ph.D., Baptiste Jean Germain )
• B05 - Real-space determination of local atomic arrangements of CCSS (Project Head Morgenstern, Karina )
• C01 - Electrochemical characterisation - High-throughput electrocatalytic screening and single-entity nanoelectrochemistry (Project Head Schuhmann, Wolfgang )
• C02 - Identification of statistically distributed active SAA on a CCSS surface using zooming-in scanning electrochemical cell microscopy (SECCM) activity maps (Project Head Andronescu, Corina )
• C03 - Elucidating the influences of electrochemically tuned surface composition on the hydrogen evolution reaction at CCSS (Project Head Tschulik, Kristina )
• C04 - Identification of electroactive sites at the surface of CCSS under reaction conditions (Project Head Bandarenka, Aliaksandr )
• INF - FAIR collection, curation and management of multidimensional research data (Project Heads Banko, Lars ;  Stricker, Markus )
• MGK - Integrated Research Training Group “Understanding Surface Atom Arrangements” (Project Heads Li, Ph.D., Tong ;  Schuhmann, Wolfgang )
• S - General characterisation of thin films and surfaces (Project Head Pfetzing-Micklich, Janine )
• Z - Central tasks and coordination of the CRC (Project Head Ludwig, Alfred )

• Applicant Institution: Ruhr-Universität Bochum
• Participating University: Københavns Universitet; Technische Universität München (TUM); Universität Duisburg-Essen
• Participating Institution: Max-Planck-Institut für Nachhaltige Materialien GmbH (MPI SusMat)
• Spokesperson: Professor Dr.-Ing. Alfred Ludwig