A novel Fe3O4–graphene–Au multifunctional nanocomposite: green synthesis and catalytic application

Abstract

A facile, economical, and low-toxicity approach was proposed to coat gold nanoparticles (Au NPs) on the surface of graphene-encapsulated magnetic microspheres. The current method makes it possible to integrate Fe 3 O 4 NPs and metal NPs with graphene without any interference or site competition. Dopamine serves as a reducing agent as well as a coupling agent for the assembly of reduced graphene oxide (RGO) and Au NPs on magnetic cores, so that no additional chemicals and thermal treatments are needed. The X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) results demonstrate that GO is successfully deoxygenated by the reduction of the PDA layer, while transmission electron microscopy (TEM), scanning electron microscopy (SEM), and inductively coupled plasma mass spectrometry (ICP-MS) results indicate that plenty of Au NPs (about 7.3 nm in diameter) are homogeneously distributed onto the surface of RGO and the Au content of the composite is 13.58 wt%. The high Au content endows the nanocatalyst with great catalytic performance towards the reduction of o-nitroaniline to benzenediamine by NaBH 4 (completely transformation within 4 min). Furthermore, the as-prepared catalyst can be easily recovered and reused at least ten times due to the high magnetization and stability.

A double-shelled yolk-like structure as an ideal magnetic support of tiny gold nanoparticles for nitrophenol reduction

“…Fig. 4a shows the XRD pattern of the core-shell SiO 2 @Fe 3 16 The XRD pattern of yolk-shell SiO 2 @ Fe 3 O 4 /C (Fig. 4b) exhibits similar features to the core-shell structure, indicating that the phase structure of the magnetic component was well retained aer silica etching.…”

Synthesis of TiO2-Ag Nanocomposites via Green Route for Dye Degradation and Antimicrobial Studies

“…The antimicrobial activity was assessed by observing and measuring inhibition zones formed around the discs after incubation period. The zone of inhibition around Penicillin and TiO 2 -Ag nanocomposite discs are shown in fig (11) while numerical value of the diameter of inhibition zones was compiled in fig (12). It is noticed from the results that the diameter of inhibition zone is higher for gram negative bacteria Escherichia coli(21 mm) than that of gram positive bacteria Bacillus subtilis (13 mm).…”

“…The broad peak at 500-900 cm -1 corresponds to the Ti-O-Ti stretching vibrations, whereas the peak at 1384 cm -1 indicates vibrations of the Ti Ligands, peak at 1633 cm -1 O-H bonds in water, peak at 3450 cm -1 stretching vibrations of hydroxyl groups of Ti-OH on the surface. Further, the peak at 3884 cm -1 attributes to the -OH stretching vibrations of alcohol [11], [12]. …”

Synthesis of akageneite (beta-FeOOH)/reduced graphene oxide nanocomposites for oxidative decomposition of 2-chlorophenol by Fenton-like reaction

“…Among these materials, graphenebased composite material has gained considerable attention due to its excellent electronic properties and high surface area as well as edge reactivity [17]. The nanoparticles loaded on the graphene are not only able to prevent the aggregation of graphene from stacking but also improve the overall catalytic performance owing to the strong synergistic interaction between both components [18,19].…”