Crystallinity Variation in Seeded Growth of Gold@Silver Core‐Shell Nanocrystals: Truncated Right Bipyramids and Their Hollow Derivatives

Abstract

We report the seeded growth of gold@silver (Au@Ag) core‐shell nanocrystals with the shape of truncated right bipyramids (TRB) and their hollow derivatives obtained via a galvanic replacement reaction. In particular, by depositing Ag on single‐crystal Au seeds under kinetic control, the resultant Au@Ag core‐shell products exhibit planar defects. Morphology and structure characterization is performed to confirm the crystallinity variation and the resultant TRB shape. Considering that elemental Au and Ag have similar lattice constants and negligible lattice mismatch, this phenomenon is quite unique, as the crystallinity of product is typically governed by the seed. The size of final product can be controlled in the range of 37–85 nm by varying the volume of the Au seed solution. In addition, by reacting with gold precursor, the as‐prepared Au@Ag TRBs can be converted into Au‐based nanostructures with hollow interiors, showing absorbance properties continuously tuned in the visible range, which could find important use in photocatalysis, sensing, and fluorescence enhancement, among others.

Size-Tunable Yolk–Shell Gold–Silver Nanostructures for Photothermal Treatment of Multidrug-Resistant Bacteria

“…On one hand, since the quaternary ammonium group could coordinate with Ag or Au precursors, a longer alkyl chain could make the growth and etching progress in a milder way. In this case, the formed Ag layer would inherit the single-crystal nature of Au seeds rather than bring in lamellar defects via less-controlled epitaxial growth. , On the other hand, the double-layered micelles composed of DCTA groups with a larger size would help stabilize nanoparticles from aggregation . Therefore, the use of DCTAC as the capping agent was emphasized in the current strategy.…”

Seeded growth of gold-based nanoscale homojunctions via controlled etching regrowth and their applications for methanol oxidation reaction

“…10 nm Au seeds were generated via the methods described in our previous study and re-dispersed in water to form a stock solution at a mass concentration of 0.2 mg Au mL −1 . 45 Then, aqueous solutions of CTAC (10 mM, 5 mL), HAuCl 4 (0.5 mM, 6 mL), 10 nm Au seeds (20 μL), and AA (10 mM, 1 mL) were sequentially mixed in a 20 mL glass vial and aged for 1 h. Then, the reaction solution was mixed with aqueous solutions of H 2 PtCl 6 (20 mM, 50 μL) and AgNO 3 (2 mM, 20 μL), followed by aging at 60 °C overnight. The products were collected by centrifugation (16 000 rpm, 5 min), washed with water once, and re-dispersed in 3 mL of water as a stock solution prior to further characterization and use.…”

Yolk‐Shell AuAgPt Alloy Nanostructures with Tunable Morphologies: Plasmon‐Enhanced Photothermal and Catalytic Properties

“…Preparation of AuAgPt Alloy YSNSs: The 10 nm Au nanospheres were prepared using the method as described in our previous study. [31] They were washed and re-dispersed in water at the mass concentration of 0.2 mg Au mL À1 as stock solution. The Au@Ag core-shell NCs were prepared by mixing the aqueous solutions of DTAC (20 mM, 3 mL), Au nanospheres stock solution (20 μL), AgNO 3 (2 mM, 0.5 mL), and AA (10 mM, 0.5 mL) sequentially in a 20 mL glass vial and aged for 3 h at 60 °C.…”