Synthesis of gold nanoflowers assisted by a CH-CF hybrid surfactant and their applications in SERS and catalytic reduction of 4-nitroaniline

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2017-05, Vol.520, p.213-221
• Main Authors: Liu, Baoyong, Yang, Mei, Li, Hongguang
• Format: Article
• Language: English
• Subjects: 4-Nitroaniline; Catalysts; Gold nanoflowers; Hydrocarbon/fluorocarbon hybrid surfactant; Surface-enhanced Raman scattering
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2017.01.087

[Display omitted] •Gold nanoflowers (GNFs) have been synthesized via a one-pot method.•The CH-CF hybrid surfactant (1) plays a vital role in the formation of GNFs.•AgNO3 acts as a structure-directing agent during the synthesis of GNFs.•The GNFs can be used as substrates for surface-enhanced Raman scattering of R6G.•The reduction of 4-nitroaniline by KBH4 can be significantly accelerated by GNFs. In this paper, an effective approach was successfully developed to synthesize gold nanoflowers (GNFs) using a hydrocarbon/fluorocarbon (CH-CF) hybrid surfactant (1). Upon mixing with aqueous solution of 1 in presense of AgNO3, HAuCl4 could be reduced into GNFs by ascorbic acid (AA). Influences of aging time, concentration of HAuCl4, AgNO3, AA and 1 as well as temperature were investigated in detail. GNFs could not be obtained at the absence of AgNO3 and 1, indicating that both of them play important roles in the formation of these anisotropic gold structures. Influences of AA and temperature are relatively less pronounced, and well-defined GNFs can be synthesized in a wide range of the concentration of AA (1×10−3 mol·L−1 to 6×10−3 mol·L−1) and temperature (25–50°C). The GNFs have inhomogenous cores, indicating that they are formed by the aggregation of gold crystals of smaller sizes. A two-stage growth pathway was thus proposed to explain the mechanism of the formation of GNFs. With a large surface-to-volume ratio, GNFs show surface-enhanced Raman scattering for solid R6G with enhancement factors up to a magnitude of 106. They can also be used as efficient catalysts for the reduction of 4-nitroaniline by KBH4. The strategy demonstrated here is a facile, rapid, and contrallable one-pot method for the synthesis of GNFs in aqueous solution, which will bring out a wide range of applications.