Engineering two-dimensional nanobranch architecture in PdAuAg for enhanced ethanol electrooxidation

Abstract

We report a facile synthetic strategy for crafting unique trimetallic PdAuAg nanoplates with an abundant in-plane branching structure, termed “2D nanobranches”. This distinctive architecture combines the benefits of a two-dimensional morphology with a highly dendritic, high-surface-area framework. Physicochemical characterization confirms the successful formation of the ternary alloy and the intricate branched structure. When assessed for the ethanol oxidation reaction (EOR) in an alkaline medium, the PdAuAg 2D nanobranches demonstrate enhanced specific activity, reaction kinetics, and cycling retention compared to a commercial Pd/C benchmark. In situ surface-enhanced Raman spectroscopy (SERS) reveals that the catalyst selectively promotes the C2 pathway for ethanol oxidation to acetic acid, with no detectable C–C bond cleavage, thereby elucidating the origin of its high operational efficiency. Furthermore, density functional theory (DFT) simulations suggest that a higher surface coverage of hydroxyl radicals (OH) in the alkaline environment makes a key reaction step in this pathway more energetically favorable. The enhanced performance is attributed to the synergistic interplay of the ternary composition, which modulates the electronic structure, and the unique 2D branched morphology, which provides a high density of active sites and facilitates mass transport. This work highlights the profound impact of morphological control in conjunction with multimetallic engineering for advancing electrocatalyst design.