Center for High Entropy Alloy Catalysis (CHEAC)

We identify key reactions for a future renewable society, with the common theme that both oxygen and carbon chemistry must be catalyzed simultaneously; something that challenges today’s catalysts. The central hypothesis for CHEAC is that ideal catalysts for this type of chemistry will be High Entropy Alloys (HEAs).

HEAs consist of 5 or more different elements, whose atomic positions in the crystal are determined by the entropy effect and therefore mixed randomly. As consequence, the active surface consists of millions of different possible atomic arrangements.

In catalysis, the scientific challenge is to control the active surface at the atomic scale. The conventional strategy is to microscopically control the specific structure of a uniform surface. This makes it challenging to bi-functionally catalyze both oxygen and carbon chemistry.

We propose a completely new approach to discovering catalytic materials. The key strategy is to span a range of catalytic activities on a single HEA surface. The random atomic arrangement in a HEA ensures that some surface sites will have exactly the optimal bi-functional properties, which can overcome the limitations of the uniform structures found in today’s catalysts. The stoichiometry of the HEA changes the likelihood of these different sites to occur, thus by controlling the ratio of the different elements in the HEA it is possible to tune the number of the most active sites and thereby also tune the catalytic activity. The activity is therefore controlled by probability rather than microscopically.

This is a change of paradigm and opens a new field offering a statistical approach to catalyst discovery and design.