Predicted Structures of the Active Sites Responsible for the Improved Reduction of Carbon Dioxide by Gold Nanoparticles

Gold (Au) nanoparticles (NPs) are known experimentally to reduce carbon dioxide (CO 2 ) to carbon monoxide (CO), with far superior performance to Au foils. To obtain guidance in designing improved CO 2 catalysts, we want to understand the nature of the active sites on Au NPs. Here, we employed multiscale atomistic simulations to computationally synthesize and characterize a 10 nm thick Au NP on a carbon nanotube (CNT) support, and then we located active sites from quantum mechanics (QM) calculations on 269 randomly selected sites. The standard scaling relation is that the formation energy of *COOH (Δ E *COOH ) is proportional to the binding energy of *CO ( E binding *CO ); therefore, decreasing Δ E *COOH to boost the CO 2 reduction reaction (CO 2 RR) causes an increase of E binding *CO that retards CO 2 RR. We show that the NPs have superior CO 2 RR because there are many sites at the twin boundaries that significantly break this scaling relation.