Hydrogenation as an instrument for modifying structures and properties of certain classes of intermetallics and inorganic metal-rich compounds

• Applicant: Professor Dr. Holger Kohlmann
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448675425

The project has the fundamental aim of further developing hydrogenation as an instrument for modifying structures and properties of intermetallics and inorganic metal-rich compounds, to investigate the fundamental principles of hydrogen insertion, and to establish structure-property relationships for such metal hydrides and chemical ways of their manipulation. Within the scope of the project we aim to synthesize new metal hydrides based on certain structural classes of intermetallics, as well as new intermetallics of said classes, to characterize their crystal structures, to establish structure-property relationships for the compounds in question, to characterize bonding in complex and intermetallic hydrides and the electronic state of hydrogen, to develop a working predictive approach to the reactivity of intermetallics towards hydrogen, to investigate the factors that favor hydrogenation of intermetallics (calculation of thermodynamics) and their possible connection to structure and bonding, and to formulate guidelines for potential applications of complex intermetallic-based systems for hydrogen storage, embrittlement, and catalysis. We are particularly interested in the bond systems based on d- and f-metals, since these offer a lot of possibilities for different kinds of element combinations and variations in bonding patterns, and are generally less well understood. We will study the influence of hydrogen insertion on structures and properties, focusing on several classes of compounds based on specific structure types and element ratios. These classes include binary intermetallics of the MNi3, MPd3, MPt3 and MLn3 types (M = main-group metal, Ln = lanthanide), of the MNi2 and MPd2 types (M = s, p, d, or f metal), and certain compounds of the MTX- (“111”) and ZrSiCuAs- (“1111”) types (M = alkaline earth or lanthanide; T = transition metal or Mg; X = Si, Ge, Sn). Characterization of the compounds will be based on X-ray single-crystal investigations, X-ray and neutron powder diffraction (including in situ studies), electron microscopy, microprobe analysis, thermal analysis, and galvanomagnetic measurements. Electronic structures will be studied based on DFT calculations and bonding analysis will be performed both in direct and orbital space. Joint research of the groups from Lomonosov Moscow State and Leipzig Univ. will make use of the complementarity of both sides regarding expertise and infrastructure, and will also offer an opportunity of regular researcher exchange in order to disseminate specific knowledge and expertise between both groups. As a result, we expect to gain new systematic knowledge about hydrogenation of intermetallics, the principles governing stability of the structures of hydrides, the structure-property relationships in complex inorganic hydrides and chemical ways of tuning said properties; we also aim to develop recommendations on the potential use of the compounds in question as the basis for new functional materials.

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Cooperation Partner: Professor Dr. Alexey Kuznetsov, until 3/2022