Researchers at Ruhr-Universität Bochum (RUB) and Max-Planck-Institut für Eisenforschung have developed an alloy made up of five elements that is noble metal-free and as active as platinum. Non-noble elements and their alloys usually have lesser effective catalytic properties than those of noble elements. This development of one alloy made up of five almost equally balanced components offer much better properties. This is because of the so-called high entropy effect which results in catalytic activity for an oxygen reduction that is similar to that of platinum. By optimizing the composition further, they successfully improved the overall activity.
During the search for an alternative to platinum, researchers at the RUB Chair of Materials for Microtechnology headed by Professor Alfred Ludwig deployed a special method to generate an alloy nanoparticle library of five source elements. Their atoms blend in plasma and form nanoparticles in a substrate of ionic liquid. The liquid is placed in small cavities on a carrier. If the nanoparticles are located in the vicinity of the respective atom source, the percentage of atoms from that source is higher in the respective particle. In the center of the carrier, all five elements are present in more or less equal quantities. This combinatorial process enabled the researchers to precisely control the composition of the alloy nanoparticles anywhere in the material library.