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My current research interests


Surface science & Nanotechnology

My field of research is commonly called Experimental Surface Science. Surface Science is a relatively broad field situated somewhere between physics, chemistry and material science. In the last years, it has undergone quite some changes due to the tremendous evolution of Nanotechnology, an area that is heavily depending on our progress in Surface Science. This is due to the fact that, the smaller things get, the more important become their surface-(2D)- compared to their volume-(3D)-properties. This poses some challenges, but opens as well up for some new and very exciting possibilities, e.g. to produce materials with custom-tailored properties, like new catalysts that might benefit the environment and the economy.

Nanocatalysis

One of the areas, where we believe that nanotechnology quite soon will have a major impact on our daily life, is nanocatalysis. In a catalyst, only the very surface atoms are active. As catalysts are very often very expensive (like precious metals), typical challenges are to

In any case, we need to obtain an atomistic understanding of the catalyst's function in order to be able to rationally design better new catalysts.

How do we obtain atomistic understanding of nano properties ?

In order to learn more about this fascinating 2D world and the surface properties that might be interesting from a fundamental as well as from a technological point of view, experimental Surface Scientists either prepare so-called model systems: well-defined surfaces and/or structures, e.g. nanostructures, on these surfaces, or they use available surfaces, e.g. the surface of an industrial catalyst. After careful preparation under very clean conditions, often in Ultra-High Vacuum (UHV), they typically investigate the physical / mechanical or chemical properties. But one can as well investigate biological properties, like how biocompatible a surface (e.g. that of an implant) is. Similarly, one can investigate the signatures of interesting bulk material structures (like dislocations, grain boundaries etc) at the surface and use them to learn more about these otherwise hidden structures.

Electrocatalysis

During the last years, our section here at DTU Physics has moved more and more into the area of electrocatalysis. You can read more on the broader perpective of our work in this area here. Here at DTU, we are in the lucky situation that we both have theoretical and experimental surface scientists working on electrocatalysis in the same center, the Villum Center for the Science of Sustainable Fuels and Chemicals (V-SUSTAIN). My part in this collaboration is concerned with atomic scale microscopy and to this end we use some very special instruments:

The Scanning Tunneling Microscope (STM)—a perfect tool to gain atomistic understanding

The STM is a quite unique instrument as it potentially allows true atomic resolution on surfaces. Thus, we can study the interesting surfaces with the necessary resolution to gain the atomistic understanding necessary to optimize our systems. In my current field, electrocatalysis, this means that we can study e.g. differences in reactivity for different sites on a nanocatalyst (finally aiming at finding the active site). Or, we can study the structural changes of an electrode surface after an electrochemical reaction (e.g. corrosion). The aim is of course then to use this insight to design better catalysts.

In order to achive this goal, we both use an Combining UHV and EC gives us the best from two worlds, i.e., all the tools for surface preparation and analysis commonly available in UHV machines, plus the possibility to characterize our UHV-prepared surfaces under real electrochemical reactions.
Main Index page Last updated 24 September 2018 by Sebastian Horch.