Synthesis of Au-SiO₂ Composite Nanospheres and Their Catalytic Activity

Abstract

We report a simple and environmentally friendly approach to the synthesis of Au-SiC2 composite nanospheres. Our method presents a route for the decoration of preformed amine functionalized SiO2 nanospheres by in situ formation of Au nanoparticles at three different concentrations of Au precursor (HAuCl4). Herein, the silane coupling agent (KH-550) is used as an intermediary to connect the Au nanoparticles to the surfaces of the SiO2 nanospheres, which helps avoid the aggregation of Au nanoparticles. The crystal structure, chemical elements, morphology and catalytic properties of the Au-SiO2 composite nanospheres were analyzed by transmission electron microscopy (TEM), X-Ray powder diffraction (XRD), UV-vis-spectrophotometer (UV-vis) and X-ray photoelectron spectroscopy (XPS). The analytical results demonstrate that the Au nanoparticles (4-9 nm) were homogeneously distributed on the surface of the SiO2 nanospheres, which had a good FCC crystal structure. Moreover, the Au-SiO2 composite nanospheres exhibited good catalytic properties, measured by their ability to reduce organic dyes. The Au-SiO2 composite nanospheres are promising candidates for applications in catalysis and wastewater treatment.

Competitive Lateral Flow Immunoassay Relying on Au–SiO2 Janus Nanoparticles with an Asymmetric Structure and Function for Furazolidone Residue Monitoring

“…The high-resolution spectrum of Au 4f is fitted by two peaks at 84.0 and 87.7 eV, which could be assigned to 4f 7/2 and 4f 5/2 for metallic Au 0 species (Figure S2). Furthermore, the UV–vis spectra of AuNPs exhibit an absorption peak at 528 nm in Figure F. As the SiO 2 shell formed, Au–SiO 2 Janus NPs exhibit a 5 nm red shift because the coating of silica on Au increased the local refractive index .…”

Replacement of Volatile Acetic Acid by Solid SiO2@COOH Silica (Nano)Beads for (Ep)Oxidation Using Mn and Fe Complexes Containing BPMEN Ligand

“…The syntheses of SiO 2 @COOH (nano)particles were obtained ab initio starting from the synthesis of SiO 2 beads—according to a modified Stöber synthesis—using Si(OEt) 4 (TEOS) as precursor in presence of aqueous ammonia solution and H 2 O in alcohol (ethanol or methanol) as solvent ( Figure 3 ) [ 60 ]. The influence of solvent, [ 61 ] quantity of water, [ 62 , 63 ] concentration of ammonia solution [ 64 ] and temperature [ 65 ] on the size of silica nanoparticles have already been described in different articles [ 66 ].…”