Coordination: Wolfgang Schuhmann

Thin film materials libraries will be screened with respect to their catalytic HER activity with a scanning droplet cell in a defined and controlled atmosphere. This enables to select of compositions of high electrocatalytic activity and provides feedback for theoretical simulations and for the refinement of synthesis parameters. New measurement protocols will be developed to implement electrochemical surface cleaning, to collect electrolyte samples after prolonged polarisation, and sequences of voltammograms or pulses to modulate the surface atom arrangement. Lift-outs by focused-ion beam will be placed on nanoelectrodes for correlative identical-location electrochemistry/transmission-electron microscopy analyses.

Coordination: Corina Andronescu

The aim of C02 is to experimentally measure the CCSS with the highest hydrogen evolution reaction (HER) activity. To achieve this, we will use scanning electrochemical cell microscopy (SECCM) to probe the HER electrocatalytic activity on a thin-film CCSS at the nanoscale. The hypothesis is that by measuring lower areas of CCSS and thus a smaller number of SAA, the impact of the active SAA on the averaged recorded current will be higher. To prove this, we will use a so-called zooming-in approach in which we will decrease the measured area from 1 µm to 20 nm diameter. In the framework of the CRC, we will identify and characterize the CCSS areas with high electrocatalytic activity.  

Coordination: Kristina Tschulik

IN C03 we will modify the surface composition, and hence the SAA, of CCSS samples by electrochemical dealloying and underpotential deposition While the former is a selective removal of one component from the CCSS, the latter is the addition of a (sub-) monolayer of Cu or Pb on the CCSS and for both cases the extend of modifying is controlled by the transferred charge. We will determine the HER activity of the such modified samples and link activities changes to changes in the SAA, determined in collaboration with other CRC projects.

Coordination: Aliaksandr Bandarenka

A recently developed methodology based on electrochemical scanning tunnelling microscopy will be used to identify electrocatalytically active sites at the surface of specially designed model samples relevant to CCSS. The main idea is to initially use model samples consisting of two or three different metal monolayers on top of each other where the atoms at the boundaries/steps are investigated under the hydrogen evolution and oxygen reduction reaction conditions in order to monitor their activities under reaction conditions. After demonstrating the feasibility of the model samples, CCSS surfaces will be studied. Special attention will be set to further improving the resolution in the sub-nm range.