Rapid Synthesis of Hollow Ag–Au Nanodendrites in 15 Seconds by Combining Galvanic Replacement and Precursor Reduction Reactions

Abstract

Metallic nanomaterials displaying hollow interiors as well as sharp tips/branches at their surface (such as hollow nanodendrites) are attractive, because these features enable higher surface-to-volume ratios than their solid and/or rounded counterparts. This paper describes a simple strategy for the synthesis of Ag-Au nanodendrites in 15 s using Ag nanospheres prepared in a previous synthetic step as seeds. Our approach was based on the utilization of Ag nanospheres as seeds for Au deposition by a combination of galvanic replacement reaction between Ag and AuCl4(-)(aq) and AuCl4(-)(aq) reduction using hydroquinone in the presence of polyvinylpyrrolidone (PVP) as a stabilizer and water as the solvent. The produced Ag-Au nanodendrites presented monodisperse sizes, and their surface morphologies could be tuned as a function of growth time. Owing to their hollow interiors and sharp tips, the Ag-Au nanodendrites performed as effective substrates for surface-enhanced Raman scattering (SERS) detection of 4-MPy (4-mercaptopyridine) and R6G (rhodamine 6G) as probe molecules. We believe that the approach described herein can serve as a protocol for the fast and one-step synthesis of Ag-Au hollow nanondendrites with a wide range of sizes, compositions, and surface morphologies for applications in SERS and catalysis.

Addressing the Effects of Size‐dependent Absorption, Scattering, and Near‐field Enhancements in Plasmonic Catalysis

“…Figure S3A and B shows the experimental and calculated extinction UV‐VIS spectra for Ag NPs 12, 25, and 50 nm in size. While the LSPR for the 50 nm Ag NPs was located at 425 nm, a blue shift to 405 and 400 nm was observed as size decreased to 25 and 12 nm, respectively, in agreement with previous reports ,…”

Probing the catalytic activity of bimetallic versus trimetallic nanoshells

“…While bimetallic compositions allow for the combination and/or synergism of catalytic properties between the metal components, their hollow interiors provide higher surface-to-volume ratios relative to their solid analogs [4,[8][9][10][11][12][13]. In this context, several investigations on the catalytic activities of bimetallic and hollow nanostructures containing gold (Au), palladium (Pd), and platinum (Pt) have been demonstrated [14][15][16][17][18][19].…”

Nanocatalysis by noble metal nanoparticles: controlled synthesis for the optimization and understanding of activities

“…This enables one to reduce the loading of noble metals and avoid the presence of "wasted" atoms that do not come into contact with substrate molecules (atoms in the interior of a solid nanoparticle). [39][40][41][42][43][44][45] Basically, a hollow nanomaterial is characterized by the formation of a hole or void in its interior, and the precise understanding on how this hole affects the catalytic performance remains challenging. 46 With the creation of holes, an increase in the number of active sites is achieved due to larger surface areas and the fact that such structures can allow external reactants to access the interior of the nanostructures.…”