Towards a better understanding of chemical reactions at interfaces

A team of German-American researchers has developed a new method enabling chemical processes at interfaces to be analyzed more precisely than has so far been possible. Standing Wave Ambient Pressure Photoelectron Spectroscopy (SWAPPS) should now make it possible to improve our understanding of chemical processes and to use them in future in a more targeted manner, for example, to develop more effective batteries, fuel cells and photovoltaic cells. Researchers from the Peter Grünberg Institute PGI-6 in Jülich were also involved in the development of this new method, which is presented in the current edition of the renowned scientific journal "Nature Communications".

Chemical processes at interfaces play an important role in the corrosion of materials. However, they are also used in energy storage and conversion, such as in fuel cells and batteries. During these processes, the effects that occur in the very thin layers between materials in different states, for example, between liquid and gas states or solid and liquid substances are of great interest. These processes are certainly very complicated and not yet fully understood in detail. In order to improve our understanding of them, researchers are working on analyzing the structure of interfaces. SWAPPS makes it possible to examine each chemical element at interfaces even up to the sub-nanometer range, that is, on a scale smaller than a billionth of a metre. For this reason, SWAPPS combines two current methods from X-ray spectrometry, which up until now were used independently of each other: ambient pressure X-ray photoelectron spectroscopy (APXPS) and so-called standing wave (SW) spectroscopy. The advantage here over other methods is that SWAPPS does not require an ultra-high vacuum yet delivers significant results for processes which take place in high pressure, high temperature environments. This has been confirmed by experiments undertaken by the research group using a liquid film made from sodium hydroxide and caesium hydroxide on an iron oxide surface.

The project's final scientific investigations were carried out at Forschungszentrum Jülich. PGI-6 intends to develop the method further together with its American partners from the University of California, Davis, the Lawrence Berkeley National Laboratory and the IBM Almaden Research Center, and to apply it in future projects.

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Source: Forschungszentrum Jülich