Controlled synthesis and photocatalysis of sea urchin-like Fe₃O₄@TiO₂@Ag nanocomposites

Abstract

Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.

Applications of CTAB modified magnetic nanoparticles for removal of chromium (VI) from contaminated water

“…1 that proceeds from the 311 plane is characteristic of the crystal cubic phase. Zhao et al obtained similar XRD planes when they have prepared Fe 3 O 4 nanocomposite [36].…”

Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation

“…Furthermore, the nanocomposite possessed good magnetic behaviour with a magnetisation saturation of 26.5 emu¨g´1 (Figure 4), which was high enough to facilitate magnetic separation (Figure 4 insert). In addition to the degradation of AMP, the nanocomposite photocatalyst showed remarkable photocatalytic properties towards S. aureus (G + ), E. coli (G´), and A. niger [116]. In another example, improved MO decomposition was realised over Fe 3 O 4 /N-TiO 2 /Ag hollow nanospheres, reaching 99.5% in 80 min of visible light exposure when the Ag loading was 1.0% [121].…”

“…For example, Zhao et al observed enhanced photocatalytic activity towards ampicillin (AMP) over Fe 3 O 4 /TiO 2 /Ag with a sea urchin-like morphology, both under visible and UV light irradiation. The composite photocatalyst reached 98.7% and 91.5% AMP degradation after 360 min of UV and visible light illumination, respectively [116]. Furthermore, the nanocomposite possessed good magnetic behaviour with a magnetisation saturation of 26.5 emu¨g´1 (Figure 4), which was high enough to facilitate magnetic separation (Figure 4 insert).…”

“…Magnetite is by far one of the most widely exploited iron oxide magnetic nanoparticle in the fabrication of magnetic photocatalysts due to its low toxicity, good magnetic properties, biocompatibility, and remarkable adsorption properties [115,116]. The magnetisation saturation for magnetite can reach values of up to 92 emu/g, making it the ideal candidate for synthesis of magnetically separable photocatalysts [103].…”

Recyclable Magnetic Titania Nanocomposite from Ilmenite with Enhanced Photocatalytic Activity

“…In addition, in order to improve the photocatalytic activity of TiO 2 , nanostructured TiO 2 is often expected to exhibit outstanding photocatalytic performance, owing to their larger specific surface area and good dispersion in aqueous solutions [11]. However, in practical treatment processes, finely dispersed TiO 2 particles are difficult to separate and recover from a liquid phase [12]. Therefore, how to separate and recover nano-TiO 2 , and improve the visible-light-driven nano-TiO 2 , have been research hotspots [13,14].…”