(569dc) Exploring Single Atom Alloy Catalysts for Enhanced Methane Activation to C2+ Products: Insights from Computational Modeling

Conversion of earth-abundant methane into valuable liquid fuels and chemical feedstocks represents an attractive technology to effectively use natural resources without resorting to further petroleum extraction. Single atom alloy (SAA) – atomically dispersing the minimum amounts of a reactive metal in the surface layer of a less reactive host metal – holds great promise for direct methane conversion to multi-carbon hydrocarbons through engineering single active sites to enable facile C-H bond scission and host metals to allow favorable C-C coupling. This study focuses on computationally designing stable, active, and selective SAA catalysts for methane activation to C₂₊ products and elucidating possible reaction mechanisms by employing Density Functional Theory (DFT) calculations. We start from assessing structural stability of SAAs by considering both segregation and aggregation energy, which quantifies the relative stability of the single isolated dopant in the surface layer of the host versus immersed in the bulk material and the relative stability of the dopant atoms towards aggregation to form a cluster. On the identified stable SAAs, we evaluate kinetics and thermodynamics of methane dehydrogenation and subsequent C-C coupling pathways towards generating C₂₊ products. We identified several promising SAA catalysts to perform the chemistry with high activity and selectivity. Our study provides valuable insights into discovering novel catalysts for direct methane conversion, fundamental catalysis at atomic scale, and methane activation chemistry.