Engineering Trimetallic Au-Ag-Pd Superstructures through Nanoalloying for SERS-Based Weakly Adsorbing Species...

In this study, we report a tricomponent Au-Ag-Pd nanocube superstructure (SS) fabricated through a heteronanocube coassembly strategy to serve as a nanoparticle-level nanoalloy platform. Unlike conventional binary nanoalloy systems, this architecture integrates three compositionally distinct yet geometrically compatible nanocube building blocks into a single ordered aggregate, enabling cooperative plasmonic, chemical, and interfacial functionality. In this architecture, the Au nanocubes function as structurally and chemically stable plasmonic scaffolds, while the Ag nanocubes serve as the primary plasmonically active component that provides strong near-field enhancement. Additionally, the Pd nanocubes introduce chemically interactive sites with a preferential affinity for hydroxyl-containing ligands. The assembled SSs are further converted into superpowders and directly applied to contaminated surfaces, demonstrating their utility as on-site sensing materials. These findings establish tricomponent heteronanocube nanoalloying as an effective strategy for constructing cooperative plasmonic SSs with compositionally programmable and chemically selective functionality, thereby extending nanoparticle-based alloying beyond binary systems.