Speaker
Description
Industrial catalysts belong to a class of functional materials that play an important role in the sustainable use of natural resources. For the development of improved catalysts, it is of crucial importance to gain atomistic insights about the structure-function relationship. Decades of research in catalysis have demonstrated the difficulty of this task. Challenges are related to the fact that catalysts are operating far from thermodynamic equilibrium in reactions that involve processes at different time- and length scales. Their study thus requires a multi-scale approach.
For many years, electron microscopy has played an important role in the characterization of catalysts and their precursors. Atomically resolved images of catalyst particles serve as reference for theoretical modelling and have influenced the way in which we depict active sites. However, high-resolution imaging and local compositional analysis performed in vacuum and close to room temperature is of limited relevance for the description of an active catalyst. The recent development of commercial solutions for in situ transmission electron microscopy has enabled experiments under controlled liquid- and gas- environment and the study materials under the influence of a physical/chemical stimulus. Using a combination of in situ scanning and transmission electron microscopy, it is possible to realise a multi-scale approach for the study of active catalyst. By bridging the scale from the Å to the mm range and pressures from 10-5 to 10+5 Pa, it is possible to reveal the dynamic nature of active catalysts and to bridge the materials and pressure gap between simplified model systems and real-world catalysis. Examples of simple metal catalysed redox-reactions reveal structure-function relationships and fascinating insights in rate oscillations and oscillatory behaviour inherent to the action of catalysts that have to break bonds and facilitate the formation of new ones over and over again.
| Speaker Country | Switzerland |
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