Year: 2025
Type: article
Abstract: Ammonia is industrially synthesized over multi‐promoted Fe‐based catalysts for more than a century. Although ammonia synthesis reflects a prototypical catalytic reaction, rational catalyst design is still impossible as the full structural complexity of this catalyst system often referred to as ammonia iron and its structural entanglement is barely understood. Here, the mesoscopic structure of a technical, multi‐promoted ammonia synthesis catalyst is uncovered using a scale‐bridging electron microscopy approach complemented by X‐ray diffraction and spectroscopy to explore the structural integrity of ammonia iron. Amorphous contributions and structures of the melilite type and tricalcium aluminate as additional phases are identified. Furthermore, the understanding of the ammonia iron family by unveiling the role of the platelet‐Fe perimeter, framework Fe, thin film Fe, and refractory Fe is extended. Their interconnectedness is highlighted, suggesting that each component has to be present to fulfill a specific task. The study demonstrates that catalysis science can only proceed if it openly explores the full complexity of catalytic systems.
Source: Advanced Energy Materials
Authors: Kassiogé Dembélé, Jihao Wang, Maxime Boniface, Jan Folke, Luis Sandoval Diaz, Frank Girgsdies, Adnan Hammud, David Kordus, Gregor Koch, Zahra Gheisari, Raoul Blume, Wulyu Jiang, Axel Knop‐Gericke, Rene Eckert, Stephan Reitmeier, Andreas Reitzmann, Robert Schlögl, Beatriz Roldan Cuenya, Janis Timoshenko, Holger Ruland, Thomas Lunkenbein
Language: English
Subfield: Catalysis
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
OpenAlex ID: W4411434807