|The results of the sputtering process can be seen under the light microscope.|
Image Credit: © Lars Banko
New methods make it possible to produce countless new materials in one step and to examine them quickly.
When looking for catalysts for the energy transition, materials made from at least five elements are particularly promising. Only there are theoretically millions of them - how do you find the most powerful? A Bochum research team led by Prof. Dr. Alfred Ludwig, head of the Materials Discovery and Interfaces chair, MDI, managed to accommodate all possible combinations of five elements on one carrier in a single step. In addition, the researchers developed a method to analyze the electrocatalytic potential of each of the combinations in this micromaterial library in high throughput. In this way, they want to speed up the search for potential catalysts many times over. The team at the Ruhr University Bochum reports in the journal Advanced Materials.
In the production of material libraries of so-called high-level companies, the Bochum researchers use a sputtering process. All raw materials are applied to a carrier from different directions at the same time. At every point on the carrier, the starting materials are deposited in different mixing ratios. "In the current work, we have refined this process by using pinhole covers in such a way that each material mixture is only created on the carrier at a tiny point of about 100 micrometers in diameter," describes Alfred Ludwig. This is approximately the diameter of a human hair. "Thanks to the miniaturization of the material libraries, we are now able to accommodate a complete five-component system on a single carrier - an enormous advance," adds Dr. Lars Banko from the MDI Chair, who recently did that EXIST-funded startup project xemX leads.
Examination with hanging drops
The researchers use the so-called Scanning Electrochemical Cell Microscopy, or SECCM for short, to investigate the materials created in this way. The electrochemical properties of the material are measured at a certain point via a hanging nanotrop of an electrolyte with a thousand of the diameter of a hair. "This allows us to find the candidates with the highest catalytic activity in high throughput, for whom a more detailed examination seems worthwhile," says Prof. Dr. Wolfgang Schuhmann, head of the chair for analytical chemistry at the Ruhr University.
Using these methods, the researchers want to efficiently search the abundance of possible materials for new catalysts in order to find particularly active candidates in catalytically. Catalysts are needed, for example, for energy conversion processes that could, among other things, make it possible to use green hydrogen on a large scale as an environmentally friendly energy source.
The work was funded by the German Research Foundation as part of the Collaborative Research Centers / Transregios 87 (project no. 138690629) and 247 (project no. 388390466) and by the European Research Council (CasCat  and Marie Skłodowska-Curie MSCA-ITN Single-Entity Nanoelectrochemistry Sentinel ).
Published in journal: Advanced Materials
Source/Credit: Ruhr University Bochum
Reference Number: scn011623_01