Controlled synthesis of Au–Fe₃O₄ hybrid hollow spheres with excellent SERS activity and catalytic properties

Abstract

Au-Fe3O4 hybrid hollow spheres have been successfully synthesized by a one-pot process via the hydrothermal treatment of FeCl3, HAuCl4, citrate, urea, and polyacrylamide (PAM). The amount of Au nanoparticles located in the hybrid hollow spheres can be tuned by changing the molar ratio of Au/Fe precursors. A possible synthetic mechanism of the Au-Fe3O4 hybrid hollow spheres has been proposed. The obtained hybrids exhibit not only a superior surface-enhanced Raman scattering (SERS) sensitivity, but also an excellent catalytic activity. The detection limit of the Au-Fe3O4 hybrid hollow spheres (the Au/Fe molar ratio is 0.2, Au-Fe3O4-0.2) for R6G can reach up to 10(-10) M, which can meet the required concentration level for ultratrace detection of analytes using SERS. Furthermore, the catalytic experiments of the Au-Fe3O4-0.2 hybrid hollow spheres demonstrate that the model of 4-nitrophenol (4-NP) molecules can be degraded within 3 min and the catalytic activity can be recovered without sharp activity loss in six runs, which indicates their superior catalytic degradation activity. The reason may be due to the highly efficient partial charge transfer between Au and Fe3O4 at the nanoscale interface. The results indicate that the bifunctional Au-Fe3O4 hybrid hollow spheres can serve as promising materials in trace detection and industrial waste water treatment.

Hybrid Nanoparticles Based on Cobalt Ferrite and Gold: Preparation and Characterization

“…Such a hybrid catalyst material has higher efficiency and lower cost due to the larger Au surface area, compared with gold NPs. It is also worth noting that it is possible to separate the catalyst using an external magnetic field [4,5,[20][21][22][23][24][25][26]. The catalytic properties of gold-coated magnetic nanoparticles can be varied by the type of coating (thick shell or decoration with nanoclusters) and the morphology and size of gold nanoparticles on the surface.…”

Star-Shaped Fe3-xO4-Au Core-Shell Nanoparticles: From Synthesis to SERS Application

“…Star-shaped Fe 3-x O 4 -Au core-satellites and core-shell nanoparticles provide interesting magnetic and optical properties, making them appealing to broaden advances in magnetically assisted surface-enhanced Raman spectroscopy (SERS) applications [1][2][3][4][5][6][7]. On one hand, the anisotropic, in shape continuous or discontinuous gold structure with a thickness of less than 100 nm produces local high electric field enhancement, proceeding at the end of the gold tips and/or at their junctions (hot spots), for which the concentration of free electrons is high.…”

Iron Oxide and Gold Based Magneto-Plasmonic Nanostructures for Medical Applications: A Review

“…In the second strategy, the produced aggregates [ 28 , 29 , 30 , 31 , 32 , 33 ] including hollow aggregates, possess random and polydispersed NPs of iron oxide and plasmonic NPs, mainly gold. These structures are built thanks to a strong metal–oxide interaction at the interface of the two kinds of involved particles.…”

“…Hollow ones provide high specific surface and low density [ 30 , 31 , 32 , 33 ], leading to an interest in the field of high drug-loading capacity. In addition, their plasmonic components exhibit not only a superior surface-enhanced Raman scattering (SERS) sensitivity, but also an excellent catalytic activity [ 28 , 29 ].…”