The unusual effect of AgNO3 on the growth of Au nanostructures and their catalytic performance

Abstract

Au nanostructures attract much attention due to their potential applications in many fields. The controlled synthesis is critical to their properties modulation and applications. AgNO3-assisted synthesis is a widely used method for controllably preparing Au nanostructures in aqueous system. Herein, the effect of AgNO3 on the growth of Au nanostructures in polyol is studied. We observe an unusual effect that AgNO3 can induce the formation of pentatwinned Au nanostructures (nanorods and decahedra) and block the growth of Au nanorods. More interestingly, this blocking effect can be tuned through controlling the amount of AgNO3. A moderate amount of AgNO3 facilitates the formation of Au nanorods. A large amount of AgNO3 completely blocks the growth of nanorods and favors the formation of high quality decahedra (decahedra can be considered as nanorods with 0 nm longitudinal length). Besides, this blocking effect also allows preparation of different high-index-faceted Au nanobipyramids. These prepared Au nanostructures further serve as starting templates to fabricate other heterostructured Au/Ag nanomaterials, such as Ag-Au-Ag segmental nanorods, Au@Ag core-shelled nanostructures. The prepared nanostructures exhibit size- and structure-dependent catalytic performance in the reduction of p-nitrophenol to p-aminophenol by sodium borohydride.

The alloying effect and AgCl-directing growth for synthesizing a trimetallic nanoring with improved SERS

“…13 After H 2 PtCl 6 and AA were added, the mixture was heated in a 120 o C oil bath and a color change from red to gray was observed during reaction. 13 After H 2 PtCl 6 and AA were added, the mixture was heated in a 120 o C oil bath and a color change from red to gray was observed during reaction.…”

“…The products were observed with HAADF and TEM (Fig. 13,52,53 The rough nanorings ( Fig. Before reaction, the AAAD seeds have smooth surface ( Fig.…”

“…4). 13,58,59 Besides, a shoulder peak was also observed at 530 nm due to size effect that their UV-vis absorption is similar to that of two-dimensional plate-like nanostructures when decahedra size is relatively large. 4).…”

“…The decahedral colloid before etching has a strong absorption peak at 600 nm (Curve 1 in Fig. 13 After 30 min reaction, blue shift was observed because etching caused the size reduction of decahedra (Curve 2 in Fig. It is worth noting that the Ag atoms in AAAD have no strong effect on the surface plasmon resonance absorption because because of low content.…”

Facile Growth of High-Yield Gold Nanobipyramids Induced by Chloroplatinic Acid for High Refractive Index Sensing Properties

“…For example, Huang et al . produced Au NBPs using an overgrowth process by employing large sized Au decahedra as the seeds1415. However, this synthetic process involved a high temperature and complex organic agents, making it still difficult to prepare.…”