Structure–Activity Correlations of Magnesium Oxide as Support for Ruthenium‐Catalyzed Ammonia Synthesis

ABSTRACT Ammonia is emerging as a hydrogen carrier. Mitigating the harsh conditions of the Haber–Bosch process is crucial for a delocalized production, so improving the activity and stability of the catalyst might lead to a significant decrease in the energy demand. Herein, we report our results regarding the correlation between the surface structure and the catalytic activity for magnesium oxide as support for the ruthenium‐based ammonia synthesis. Quantum mechanical calculations via DFT were performed to determine the stability of single ruthenium atoms, as well as catalytically active (b5) sites on different MgO surfaces. The adsorption energy of ruthenium on the different MgO surfaces with the Miller indices of (200), (220), and (111) was determined and compared with the bulk formation energy of ruthenium to examine the influence of the surface structure on the catalytic activity. To support the results, MgO with different surface structures was synthesized on different routes. Finally, the MgO was further processed to a Ru‐based catalyst promoted with Cs, and its activity as a catalyst was tested. A possible correlation between an increase in the MgO(111) and higher catalytic activity and stability has been shown.