Nanoscale Engineering of 3D Intragaps and Compositions in Multimetallic Hollow Superstructures for Enhanced Catalysis.

Designing and synthesizing multishelled metallic hollow nanostructures with intragaps and porous shells have received widespread attention for enhancing optical and catalytic properties. However, significant challenges remain in engineering these structures at the nanometer scale. Herein, we employed the galvanic replacement reaction (GRR) method to prepare multimetallic hollow superstructures with 3D cavities and distinct nanometer intragaps. By precise control of the intragap distances (1-10 nm) and composition distributions within a single entity, libraries of multimetallic hollow superstructures were constructed. Using the 4-nitrophenol reduction as a model reaction, triple-shell Au@Pt-Ag nanoparticles with approximately 1 nm intragaps exhibited a catalytic rate 211.6 times higher than that of commercial Pt/C catalysts. The nanoconfinement environment of multishelled structures not only increases active sites but also promotes electron delocalization of reactants, accelerating the hydrogenation process both thermodynamically and kinetically. Our work advances the rational synthesis of multishelled nanostructures, expanding their potential applications in catalysis, plasmonics, and biosensing.