Superparamagnetic Ag@Fe3O4 core–shell nanospheres: fabrication, characterization and application as reusable nanocatalysts

Abstract

Superparamagnetic Ag@Fe(3)O(4) nanospheres with core-shell nanostructures have been prepared by a facile one-pot method. The diameter of the as-synthesized nanospheres was about 200 nm and the core sizes were between 50 and 100 nm. By varying the concentrations, particles with tunable core size and total size are successfully achieved. Time dependent experiments were constructed to investigate the synthesis mechanism, which indicated that the present method corresponded to an Ostwald ripening progress. The BET area of the core-shell nanospheres is about 22.6 m(2)/g and this result indicates that the product shows a porous character. The saturated magnetization of the superparamagnetic Ag@Fe(3)O(4) nanospheres is 27.4 emu g(-1) at room temperature, which enables them to be recycled from the solution by simply applying a small magnet. Due to the unique nanostructure, these particles show high performance in catalytic reduction of 4-nitrophenol and can be used as reusable nanocatalysts.

Biomolecule functionalized magnetite nanoparticles efficiently adsorb and remove heavy metals from contaminated water

“…However, MNP ST , and MNP CS were found less agglomerated, which reveals that starch and casein capping can prevent the agglomeration of MNPs (Fig. (B,C)) . Further, we confirmed that the average size of the MNP ST and MNP CS were ∼7.1 and ∼9.0 nm respectively.…”

“…1(B,C)). 41 Further, we confirmed that the average size of the MNP ST and MNP CS were ∼7.1 and ∼9.0 nm respectively.…”

A Facile Synthesis of Multifunctional Iron Oxide@Ag Core–Shell Nanoparticles and Their Catalytic Applications

“…Fe 3 O 4 @Ag nanoparticles, reported by Xuan et al, took about 40 min for the catalytic reduction with a rate constant of 8 × 10 –4 s –1 62. Jiang et al have reported iron oxide@silver core–shell nanocomposite for the reduction, and the time taken is about 30 min 63. Zhu et al have reported the conversion of 4‐nitrophenol to 4‐aminophenol in 4 min using Fe 2 O 3 @C@silver core–shell nanostructures, and the rate constant was found to be 1.03 min –1 25.…”

Fabrication and evaluation of controllable core/shell magnetic molecular imprinted polymers based on konjac glucomannan for trichlorfon

“…As shown in Figure (d), EDS demonstrated that Fe 3 O 4 contained more Fe and less C. The Fe signal consisted of the characteristic peaks of the magnetite nanoparticles, and the less intense C signal might originate from the carbon‐coated copper grid . The N signal as shown in Figure (e,f) was assigned to the graft monomer (AM), which proved that the polymer shell was successfully coated on the surface of the Fe 3 O 4 nanoparticles .…”