Preparation And Properties Of Gold Nanoparticles With Different Morphology And Surface Structure

Nano-scale gold materials exhibit different properties from bulk gold materials due to their size effect,including high electron density,dielectric properties,and high-efficiency catalytic properties,and are therefore widely used in biosensing,biomedicine,and catalysis and other fields.Gold nanoparticles dominated by different morphologies and different crystal planes have different optical properties.Therefore,the preparation of controllable morphology and uniform and stable gold nanoparticles with good dispersion is very important for its further application.In this paper,chemical reduction is used to synthesize gold nanoparticles,gold nanoplates,gold nanorods,and corolla gold nanoplates with good dispersibility.The synthesized gold nanoparticles were characterized by ultraviolet-visible absorption spectroscopy,transmission electron microscopy,scanning electron microscopy,X-ray photoelectron spectroscopy,and Xray powder diffraction.The effects of surface ligands,reaction temperature,etc.on the product morphology and surface structure during the reaction were explored.The monodisperse gold nanoparticles with different morphologies were constructed into a surface-enhanced Raman scattering substrate by self-assembly.The catalytic activity of gold nanoparticles with different morphologies as surface-enhanced Raman scattering substrates was studied.In addition,the performance differences of gold nanoplates with different crystal planes were explored.The content of this paper mainly includes the following two aspects:(1)Using sodium citrate,borane tert-butylamine and ascorbic acid as reducing agents,gold nanoparticles,gold nanoplates and gold nanorods were synthesized respectively.Three kinds of gold nanoparticles with different morphologies were prepared into surface-enhanced Raman scattering substrates by self-assembly method to study the catalytic activity of gold nanoparticles with different morphologies as surface-enhanced Raman scattering substrates.(2)Using ethylenediaminetetraacetic acid(EDTA)and polyvinylpyrrolidone(PVP)as coreducing agent and morphology-directing agent,a corolla-shaped gold nanoplates with(110)crystal plane was successfully synthesized.Based on the energy sequence of different gold crystal planes ?(111)<?(100)<?(110),the(110)plane has the highest surface energy in the low refractive index plane.In this work,gold nanocrystals exposed to high energy(110)planes were prepared.Through SEM,TEM,XRD,XPS and electrochemical characterization,the structure and formation mechanism of the corolla gold nanoplates were explored.