Plasmonic and catalytic Au NBP@AgPd nanoframes for highly efficient photocatalytic reactions

Heterogeneous metal nanostructures with excellent plasmonic performance and catalytic activity are urgently needed to realize efficient light-driven catalysis. Herein, we demonstrate the preparation of hollow Au nanobipyramid (NBP)@AgPd nanostructures by employing Au NBP@Ag nanorods as templates. The products could transform from Au NBP@AgPd nanoframes to nanocages, along with the redshift and broadening of the plasmon wavelength. Particularly, the plasmon intensity of these nanostructures remained considerable among the shape evolution process. Based on the selective absorption of CTAB, the Ag atoms on the side surfaces of the Au NBP@Ag nanorods were employed as the sacrificial templates to reduce Pd atoms through galvanic replacement. The reduced Pd and Ag atoms produced through the reduction reaction were preferably co-deposited on the corners and edges at the early stage and later deposited directly on the defect sites of the side facets, as more Ag atoms were released. The discontinued distribution of the Pd atoms gives an opportunity to etch away the Ag atoms in the cores, leading to the formation of hollow Au NBP@AgPd nanostructures after the etching process. It is worth noting that the deposition of the ultrathin AgPd nanoframe had little influence on the plasmonic properties of Au NBPs, as verified by electrodynamic simulations. The Au NBP@AgPd nanoframe showed great photocatalytic activity toward Suzuki coupling reactions under laser irradiation. Taken together, these results suggest that the hot electrons successfully transfer from Au NBP to the AgPd nanoframes to participate in the photocatalytic reactions. This study affords a promising route for the synthesis of anisotropic bimetallic nanostructures with excellent plasmonic performances.