Growth of Porous Ag@AuCu Trimetal Nanoplates Assisted by Self-Assembly.

Wan-Cheng Zhang,Meng-Dai Luoshan,Chu-Yun Huang,Si-Jing Ding,Li Zhou,Peng-Fei Wang,Qu-Quan Wang

doi:10.3390/nano10112207

Abstract

The self-assembly process of metal nanoparticles has aroused wide attention due to its low cost and simplicity. However, most of the recently reported self-assembly systems only involve two or fewer metals. Herein, we first report a successful synthesis of self-assembled Ag@AuCu trimetal nanoplates in aqueous solution. The building blocks of multibranched AuCu alloy nanocrystals were first synthesized by a chemical reduction method. The growth of Ag onto the AuCu nanocrystals in the presence of hexadecyltrimethylammonium chloride (CTAC) induces a self-assembly process and formation of Ag@AuCu trimetal nanoplates. These nanoplates with an average side length of over 2 μm show a porous morphology and a very clear boundary with the branches of the as-prepared AuCu alloy nanocrystals extending out. The shape and density of the Ag@AuCu trimetal nanoplates can be controlled by changing the reaction time and the concentration of silver nitrate. The as-assembled Ag@AuCu nanoplates are expected to have the potential for wide-ranging applications in surface-enhanced Raman scattering (SERS) and catalysis owing to their unique structures.

Highlights

Metal nanostructures, such as AuAg, AuPt, and AuCu bimetal nanocrystals, have attracted extensive attention for decades owing to their outstanding applications ranging from plasmonics to catalysis [1,2,3,4,5,6,7]
We developed a successful synthesis of Ag@AuCu trigonal and hexagonal nanoplates assisted by self-assembly
The as-synthesized nanoplates are expected to have the potential for wide-ranging surface-sensitive applications, such as catalysis, surface plasmon resonance (SPR), and surface-enhanced Raman scattering (SERS) due to their unique structures

Summary

Introduction

Metal nanostructures, such as AuAg, AuPt, and AuCu bimetal nanocrystals, have attracted extensive attention for decades owing to their outstanding applications ranging from plasmonics to catalysis [1,2,3,4,5,6,7]. Apart from the synthesis of metal nanocrystals with various configurations such as core–shell structures [8,9,10,11,12] and alloy structures [13,14,15,16,17,18], researchers have found that self-assembling metal nanocrystals into some unique structures can bring a series of fascinating properties. The droplet evaporation method, which contains three main forces (i.e., van der Waals force, depletion force, and electrostatic force), is a popular way to obtain self-assembled nanostructures [37,38,39,40]. Due to the charming optical properties of surface plasmon resonance (SPR) for gold and silver [56,57,58,59], the self-assembled nanostructures consisting of Au and Ag nanocrystals are the most reported. The as-synthesized nanoplates are expected to have the potential for wide-ranging surface-sensitive applications, such as catalysis, SPR, and SERS due to their unique structures

Materials

Synthesis of AuCu Alloy Nanocrystals

Characterizations

Growth of Multibranched AuCu Alloy Nanocrystals