Theoretical understanding and prediction of metal-doped CeO2 catalysts for ammonia dissociation

Abstract

Ammonia plays a critical role in energy and environmental catalysis, particularly in ammonia dissociation reactions. Understanding the adsorption and dissociation of ammonia-related species on catalysts is essential for the development of new chemical reactions and high-performance catalysts. However, establishing the relationship between catalyst properties and the adsorption of dissociated species remains challenging, particularly for metal oxide catalysts. This study employs density functional theory calculations to investigate the adsorption properties of ammonia and dissociated intermediate species on metal-doped CeO₂. Through a feature correlation heat map, certain descriptors, such as single atom formation energy, gaseous atom formation heat, valence band maximum, and work function, were determined to exhibit a strong linear relationship with the adsorption properties of NH_x species. As deduced from the density of states properties and orbital theory, it is also found that the energy difference between the lowest unoccupied orbital of the metal and the highest occupied orbital of ammonia, has a good relationship with the adsorption energy of NH₃.