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 during catalyst 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. Certain descriptors, such as single-atom energy, gaseous atom formation heat, valence band maximum, and work function, were determined to exhibit a strong linear relationship with adsorption properties of NHx species. Using a feature correlation heat map, the relationship between the valence band maximum and adsorption properties was found to be primarily influenced by the lowest unoccupied orbital of the metal and the highest occupied orbital of ammonia, as deduced from the density of states properties and orbital theory.