Metal nitrides as electrocatalysts in green ammonia synthesis

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2024-10, Vol.130 (10), Article 771
• Main Authors: Januszewska-Kubsik, A., Podsiadło, S., Pudełko, W., Siekierski, M.
• Format: Article
• Language: English
• Subjects: Ammonia; Characterization and Evaluation of Materials; Chemical bonds; Chemical synthesis; Condensed Matter Physics; Electrocatalysts; Electrochemistry; Energy of dissociation; Free energy; Heat of formation; Heterostructures; Industrial development; Machines; Manufacturing; Metal nitrides; Nanotechnology; Nitrogen; Optical and Electronic Materials; Physics; Physics and Astronomy; Plant layout; Processes; S.I. : XVI Polish Conference for Fast Ionic Conductors; Stoichiometry; Substrates; Surfaces and Interfaces; Sustainable development; Thin Films; XVI Polish Conference for Fast Ionic Conductors
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-024-07918-5

Green ammonia is assumed to be an important part of the European hydrogen economy and one of the most important substrates of chemical industry. The future development of its manufacturing processes can be related to the electrocatalytic studies yielding in the development of the catalytic materials that would effectively break the nitrogen-nitrogen bond to successfully drive the N 2 RR—a process of molecular nitrogen electroreduction to ammonia. Molecular nitrogen is characterized with strong triple bond energies (942 kJ/mol) which leading into large dissociation energy of N 2 (9,76 eV) and also large energy barrier of the first step of triple bond dissociation 410 kJ/mol (4,25 eV). Those large energies makes reduction to ammonia an extremely difficult task. Metal nitrides of d and f block became in interest due to their activity in ammonia production from molecular nitrogen and hydrogen. Practically all the transition elements occurs in one of the four types of crystalline structures: regular, regular face cantered, hexagonal and hexagonal close packed. The reactions of these metals with nitrogen (or ammonia) typically yields in nitride compounds of an identical type of crystalline structure as the initial metal. Dealing with single metal systems, their ternary counterparts and metal–metal nitride heterostructures, the presented review shows that nitrides are promising groups of electrocatalytic materials. Being property-prone to their internal structural features such as non-stoichiometry and correlated concentration of nitrogen vacancies, metal nitrides are a good candidate for joined investigations spanned between electrochemistry, inorganic chemistry and material engineering.