Intermetallic Electrides: New Promising Materials for Ammonia Catalytic Synthesis – Intermetalyst

The Intermetalyst project aims to explore in details novel supported catalysts based on electride-like intermetallics RTX (R = rare-earth; T = transition metal; X = Si, Ge) to enhance the catalytic synthesis of ammonia and hence reduce its energy consumption. Electrides are crystals that contain excess electrons periodically located in crystallographic sites throughout the lattice. The ability of these RTX materials to transfer these electrons promotes the dissociation of an adsorbed molecule by weakening its chemical bond. This study is highly motivated by the discovery of the outstanding catalytic activity of the LaScSi silicide when combined with ruthenium. Besides, the very promising preliminary results obtained by the consortium for some other RTX intermetallics suggest that the LaScSi performances could be improved. The excellent catalytic activities of such type of materials are ascribed to their ability to supply electrons to Ru and absorb reversibly hydrogen in the working conditions of NH3 synthesis (N2+H2), preventing notably H poisoning of the Ru surface. Additionally, these materials are stable under ammonia synthesis conditions and do not necessitate high specific area. In this project divided in 5 Work Packages, we will synthesize these RTX intermetallics and determine their hydrogen sorption properties, as well as their electronic properties (including DFT calculations) and catalytic performances. The Intermetalyst project will be jointly led by experts of intermetallics and hydrides materials at ICMCB and specialists of catalysis at IC2MP. Finding stable non-toxic electrides materials, able to boost the Ru-based catalysis at ambient pressure as well as prevent the H poisoning of Ru, is a hot topic and will be a real breakthrough in the field of catalysis and sustainable chemistry.