I am working on how surface structures change during catalytical or electrochemical reactions. This is usually done on simplified systems compared to the ones used in industry such as high vacuum environments or surfaces with only one crystalline orientation (single crystals). This is due to limitations in our experimental methods where they are either able to distinguish complex surface structures, but not under realistic conditions, or, as with classical Surface X-ray Diffraction (SXRD), they can measure in realistic environments such as in electrolytes but can only measure simple materials. SXRD uses an X-ray beam with a grazing incidence angle compared to the surface. This limits the penetration depth into the sample which allows us to study the signal from the surface, but it also gives a very large beam footprint, which is the area covered by the x-ray beam. Since you get information from a large area of the sample, the method is classically used on samples that only have one structure.

What we are now studying is polycrystals, surfaces with different grains of various orientations. Studying these samples has two advantages: you can study many orientations at once, which is more efficient than to study them all separately, and you can study possible synergetic effects between orientations. I am working on the development of a method that we are calling Tomographic Surface X-ray Diffraction (TSXRD). This takes the advantages of SXRD but gives results where you can distinguish the structure of different parts of the surface. The project entails measurements of various samples and systems. These are all performed at synchrotrons such as MAX IV or DESY in Hamburg, where the X-rays can provide high-resolution measurements. A large part of my project is then to develop the analysis of the measured diffraction data.