Enhanced Catalytic Activity of N-heterocyclic Carbene Stabilized Surface Adatoms for CO2 Reduction Reaction

Abstract Adatom engineering represents a highly promising opportunity for enhancing electrochemical CO2 reduction reaction (CO2RR). However, the aggregation of adatoms under typical reaction conditions often leads to a decline in catalyst activity. Recent studies have revealed the N-heterocyclic carbene (NHC) can stabilize surface adatoms. Herein, based on density functional theory calculations, we reveal a significant enhancement in the catalytic activity of Cu adatoms decorated with NHC molecules for CO2RR. The NHC decoration strengthens the interaction between the dxy orbital of the Cu adatom and the px orbital of the C atom, reducing the energy barriers in both CO hydrogenation and C-C coupling steps. Moreover, the CO2RR catalytic activity of the NHC decorated adatom can be further improved by tuning the side groups of NHC molecules. These results provide new insights for the design of efficient CO2RR catalysts and offer a theoretical framework that can be extended to other hydrogenation reactions.