Intermetallic compounds in catalysis

An intermetallic compound (IMC) is a single-phase material, it consists of at least two metals and has at least partially ordered crystal structure, which is different from the structure of the constituting elements. Intermetallic compounds (more than 6,000 binary are known to date) have been intensively investigated in the past with respect to their physical properties, e.g. superconductivity and magnetism. Intermetallic compounds currently stand as the main subject in the search of new thermoelectrics for efficient energy conversion. Unlike the physical properties, the chemical properties of IMCs have been so far only partially investigated for a few representative compounds.

The specific and often complex crystal structure (up to the quasi-crystals) induces a dramatically modified electronic structure compared to the constituting elements or substitution alloys. Thus each intermetallic compound shows a unique combination of crystal and electronic structure, which could be of use. We can therefore consider them as "new elements" for catalysts. Covalent interactions between atoms also ensure that the surfaces are bulk terminated and segregation of the constituents is largely suppressed. Thus the intermetallic compounds open a unique opportunity of a knowledge-based approach, which aims to optimise the crystal and electronic structure of the catalyst for each catalytic reaction.