Unraveling the Role of Orbital Interaction in the Electrochemical HER of the Trimetallic AgAuCu Nanobowl Catalyst.

Unraveling the origins of the electrocatalytic activity of composite nanomaterials is crucial but inherently challenging. Here, we present a comprehensive investigation of the influence of different orbitals' interaction in the AuAgCu nanobowl model electrocatalyst during the hydrogen evolution reaction (HER). According to our theoretical study, AgAuCu exhibits a lower energy barrier than AgAu and AgCu bimetallic systems for the HER, suggesting that the trimetallic AgAuCu system interacts optimally with H*, resulting in the most efficient HER catalyst. As we delve deeper into the HER activity of AgAuCu, it was observed that the presence of Cu allows Au to adsorb the H* intermediate through the hybridization of s orbitals of hydrogen and s, d x 2 - y 2 , and d z 2 orbitals of Au. Such orbital interaction was not present in the cases of AgAu and AgCu bimetallic systems, and as a result, these bimetallic systems exhibit lower HER activities.