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O: Fachverband Oberflächenphysik
O 88: Catalysis and surface reactions III
O 88.4: Vortrag
Donnerstag, 12. März 2026, 15:45–16:00, TRE/MATH
Investigating the Promotion Mechanism of Lanthanum on Cobalt Model Catalysts for Ammonia Production — •Clara C. Aletsee, Lau H. Wandall, Emanuel Biletter, and Ib Chorkendorff — DTU, Copenhagen, Denmark
Developing catalysts for ammonia synthesis under milder conditions than the Haber-Bosch process has gained significant interest. Recent studies demonstrate that usually unreactive magnetic materials, such as cobalt, can be activated for NH3 synthesis by adding lanthanum.(1,2) According to theoretical calculations, this is attributed to not only an electrostatic, but also a beneficial spin promotion effect.(3) Herein, we examine the role of the promoter form on the catalytic performance. For this, either metallic La or La2O3 was deposited on a stepped Co(10-115) single crystal surface via e-beam evaporation. Additionally, mass-selected Co nanoparticles were deposited on two different magnetron-sputtered film supports: LaN and La2O3. All catalysts were characterized by X-ray photoelectron spectroscopy and low-energy ion scattering before and after reaction, and their activity was measured between 350-500∘C at 1 bar in a UHV-compatible cell.(4) We show that Co/La2O3 exhibits the same activity as the LaN supported catalyst system at 350∘C, but the stability decreases at higher temperatures.
References: (1) K. Zhang et al., Science 383, 1357 (2024). (2) T. N. et al., Nature 583, 391 (2020). (3) A. Cao et al., Nat Commun. 13 (2022). (4) K. Zhang et al., Rev. Sci. Instrum. 94, 114102 (2023).
Keywords: Cobalt; Lanthanum; Ammonia; Promotion; Catalysis