Graphene Fe3O4 Research Articles

Bioinspired 2D-Carbon Flakes and Fe3O4 Nanoparticles Composite for Arsenite Removal.

Development of carbon-based materials has received tremendous attention owing to their multifunctional properties. Biomaterials often serve as an inspiration for the preparation of new carbon materials. Herein, we present a facile synthesis of a new bioinspired graphene oxide-like 2D-carbon flake (CF) using a natural resource, waste onion sheathing (Allium cepa). The 2D-CF was further decorated with crystalline Fe3O4 nanoparticles for applications. Superparamagnetic Fe3O4 nanoparticles (7 nm) were well-dispersed on the surface of the 2D-CF, which was characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, Raman spectrometry, and transmission electron microscopy. Batch As(III) adsorption experiments showed that aqueous arsenic ions strongly adsorbed to the Fe3O4@2D-CF composite. The adsorption capacity of the Fe3O4@2D-CF composite for As(III) was 57.47 mg g(-1). The synergetic effect of both graphene oxide-like 2D-CF and Fe3O4 nanoparticles aided in excellent As(III) adsorption. An As(III) ion adsorption kinetics study showed that adsorption was very fast at the initial stage, and equilibrium was reached within 60 min following a pseudo-second-order rate model. Owing to the excellent superparamagnetic properties (52.6 emu g(-1)), the Fe3O4@2D-CF composite exhibited superb reusability with the shortest recovery time (28 s) among reported materials. This study indicated that Fe3O4@2D-CF composites can be used for practical applications as a global economic material for future generations.

Magnetic reduced graphene oxide nanocomposite as an effective electromagnetic wave absorber and its absorbing mechanism

A magnetic reduced graphene oxide (MRGO) composite consisting of graphene oxide and Fe3O4 particles in the range of 5–20nm has been prepared by the one-pot hydrothermal process. RGO nanosheets provide flexible substrates for nanoparticle decoration, while Fe3O4 nanoparticles can also effectively prevent nanosheets to restack each other. Compared with previously literature, the synthesized RGO-Fe3O4 composite exhibits excellent electromagnetic wave absorption. The minimum reflection loss (RL) value of −49.05dB has been observed at 14.16GHz with a thickness of 2.08mm. The absorption bandwidth (RL<−10dB) corresponding to the minimum RL is 4.60GHz. The electromagnetic wave absorption properties of the RGO-Fe3O4 composite have been interpreted through the quarter-wavelength matching model.

Optically Active Particles with Tunable Morphology: Prepared by Embedding Graphene Oxide/Fe3O4 in Helical Polyacetylene.

We report a novel and straightforward methodology for constructing hybrid particles with tunable morphology (spherical vs nonspherical) by embedding inorganic components (graphene oxide and/or Fe3O4 nanoparticles) inside chiral helical polyacetylene. Scanning electron microscopic images ascertain the spherical or nonspherical morphology of the particles. The intense circular dichroism effects demonstrate that the hybrid particles (spherical, ellipsoid-like, and cake-like) possess remarkable optical activity. The use of the chiral magnetic hybrid particles in enantioselective crystallization of racemic phenylalanine demonstrates the kind of particles' significant potential applications in chiral technologies and chiral processes. The study not only creates an unprecedented type of chiral hybrid particles, but also provides a versatile strategy for preparing advanced functional hybrid particles with tunable morphology from polymers and even from inorganic and metallic materials.

A novel biosensor based on electro-co-deposition of sodium alginate-Fe3O4-graphene composite on the carbon ionic liquid electrode for the direct electrochemistry and electrocatalysis of myoglobin

A novel biosensor based on electro-co-deposition of myoglobin (Mb), sodium alginate (SA), Fe3O4-graphene (Fe3O4-GR) composite on the carbon ionic liquid electrode (CILE) was fabricated using Nafion as the film forming material to improve the stability of protein immobilized on the electrode surface, and the modified electrode was abbreviated as Nafion/Mb-SA-Fe3O4-GR/CILE. FT-IR and UV–vis absorption spectra suggested that Mb could retain its native structure after being immobilized in the SA-Fe3O4-GR composite film. The electrochemical behavior of the modified electrode was studied by cyclic voltammetry, and a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode, which was ascribed to the good electrocatalytic capability of Fe3O4-GR composite, the good biocompatibility of SA and the synergistic effects of SA and Fe3O4-GR composite. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α) and the electron transfer rate constant (k s) were calculated as 0.982, 0.357 and 0.234 s−1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) with wide linear range from 1.4 to 119.4 mmol/L, low detection limit as 0.174 mmol/L (3σ), good stability and reproducibility.

Facile preparation of amino functionalized graphene oxide decorated with Fe3O4 nanoparticles for the adsorption of Cr(VI)

A novel ternary magnetic composite consisting of graphene oxide (GO), diethylenetriamine and Fe3O4 nanoparticles (AMGO) were synthesized by a facile one-step reaction route and characterized. The AMGO was applied as a magnetic adsorbent for the Cr(VI) removal from aqueous solutions and the magnetic separation process only took 40s. The maximum adsorption capacity of the AMGO for Cr(VI) was 123.4mg/g, displaying a high efficiency for the removal of Cr(VI), which was much higher than that of MGO. The removal process was pH dependence, endothermic and spontaneous. The pseudo-second-order model described well the adsorption kinetic data and the Langmuir isotherm model fitted the experimental data better than the Freundlich isotherm model. XPS analysis revealed that the Cr(VI) was reduced to the low-toxicity Cr(III) during the adsorption process. Both the Cr(VI) adsorption and subsequent reduction of adsorbed Cr(VI) to Cr(III) contributed to the Cr(VI) removal. In addition, the excellent reproducibility indicate that the AMGO may be a promising adsorption material for the separation and preconcentration of Cr(VI) ions from aqueous solutions in environmental pollution cleanup.

Optically Active Hybrid Materials Constructed from Helically Substituted Polyacetylenes.

Functional materials derived from synthetic helical polymers are attracting increasing interest. Helically substituted polyacetylenes (HSPAs) are especially interesting as typical artificial helical polymers. In recent years, we designed and prepared a series of functional materials based on HSPAs and inorganic materials. The target is to establish some novel hybrid materials that combine the superior properties of both. The examined inorganic materials include silica, graphene, and magnetic Fe3 O4 nanoparticles. Such new functional materials hold great promise and are expected to find practical applications, for instance, as chiral absorbents, chiral sensors, chiral selectors for inducing enantioselective crystallization, chiral catalysts towards asymmetric catalysis, and chiral carriers for enantioselective release. The Personal Account summarizes our major achievements in preparing optically active hybrid materials. We hope it will speed up progress in chiral-related research areas.

Recent developments in hybrid iron oxide–noble metal nanocatalysts for organic reactions

A review of recent developments in the synthesis of hybrid iron oxide–noble metal nanocomposites and their application to various organic reactions is presented herein. Focus is placed on various strategies for achieving (1) Au nanoparticles (NPs) on Fe3O4@polymer catalysts, (2) optimized dispersion and stability of Fe3O4/Pd catalysts, (3) Au NPs supported on Fe2O3–graphene oxide hybrid nanosheets and (4) rose-like Pd–Fe3O4 hybrid nanocomposite-supported Au nanocatalysts. Further application of such hybrid nanocomposites as catalysts for various organic reactions is discussed in brief.

Effect of GO-Fe3O4 and rotating magnetic field on cellular metabolic activity of mammalian cells

The effect of hybrid material-graphene flakes with Fe3O4 nanospheres (GO-Fe3O4), graphene oxide (GO) and magnetite nanospheres (Fe3O4) in rotating magnetic field on mammalian cells metabolism has been studied. Several reports shown that exposure to magnetic field may have influence on cellular membrane permeability. Thus, the aim of presented study was to determine the cellular response of L929 fibroblast cells to nanomaterials and rotating magnetic field for 8-h exposure experiment. The GO had tendency to adsorb proteins, thus cell metabolism was decreased and the effect of that mechanism was enhanced by impact of nanospheres and rotating magnetic field. The highest reduction of cellular metabolism was recorded for WST-1 and NR assays at concentration 100 µg/mL of all tested nanomaterials and magnetic induction value 10.06 mT. The lactate dehydrogenase leakage assay has shown significant changes in membrane permeability. Further studies need to be carried out to precisely determine the mechanism of that process.

Sodium-Ion Storage Properties of FeS-Reduced Graphene Oxide Composite Powder with a Crumpled Structure.

The sodium-ion storage properties of FeS-reduced graphene oxide (rGO) and Fe3O4 -rGO composite powders with crumpled structures have been studied. The Fe3 O4 -rGO composite powder, prepared by one-pot spray pyrolysis, could be transformed to an FeS-rGO composite powder through a simple sulfidation treatment. The mean size of the Fe3O4 nanocrystals in the Fe3O4 -rGO composite powder was 4.4 nm. After sulfidation, FeS nanocrystals of size several hundred nanometers were confined within the crumpled structure of the rGO matrix. The initial discharge capacities of the FeS-rGO and Fe3O4 -rGO composite powders were 740 and 442 mA h g(-1), and their initial charge capacities were 530 and 165 mA h g(-1), respectively. The discharge capacities of the FeS-rGO and Fe3O4 -rGO composite powders at the 50th cycle were 547 and 150 mA h g(-1), respectively. The FeS-rGO composite powder showed superior sodium-ion storage performance compared to the Fe3O4 -rGO composite powder.

A fluorescent imaging assay of cast in renal disease based on graphene quantum dots and Fe3O4 nanoparticles

BackgroundRenal disease has become a global public health problem. Cast is a useful disease marker of kidney injury and renal failure. Hence, a cast-targeted fluorescent imaging assay is developed for the laboratory diagnosis of renal disease. MethodsFirstly, graphene quantum dots (GQDs) were stripped from graphene oxide sheets and amine-modified. Then, anti-human IgG antibody was conjugated with Fe3O4 nanoparticles to identify the cast in urine. Furthermore, the modified GQDs were linked onto the surface of Fe3O4/anti-IgG nanocomposites. Lastly, this Fe3O4/GQD fluorescent probe was added into the sample to detect the cast through fluorescent imaging. ResultsPreliminary application of this probe in clinical detection showed that the common types of casts in urine (including RBC, WBC, fatty and granular casts) could be detected by this fluorescent imaging assay. The method has the advantages of fast speed, high sensitivity (lowest detection limit to 2casts/ml), good selectivity, and wide linear range (2–2000casts/ml). Regression analysis also showed that there was a good linear relationship (y=0.9495×+10.974, R2=0.9879) between the fluorescent counts and the casts in urine. ConclusionThis cast-targeted fluorescent imaging assay may be a potential method for the laboratory diagnosis of renal disease.

One-step preparation of graphene nanosheets via ball milling of graphite and the application in lithium-ion batteries

An improved method for mass production of good-quality graphene nanosheets (GNs) via ball milling pristine graphite with dry ice is presented. We also report the enhanced performance of these GNs as working electrode in lithium-ion batteries (LIBs). In this improved method, the decrease of necessary ball milling time from 48 to 24 h and the increase of Brunauer–Emmett–Teller surface area from 389.4 to 490 m2/g might be resulted from the proper mixing of stainless steel balls with different diameters and the optimization of agitation speed. The as-prepared GNs are investigated in detail using a number of techniques, such as scanning electron microscope, atomic force microscope, high-resolution transmission electron microscopy, selected area electron diffraction, X-ray diffractometer, and Fourier transform infrared spectroscopic. To demonstrate the potential applications of these GNs, the performances of the LIBs with pure Fe3O4 electrode and Fe3O4/graphene (Fe3O4/G) composite electrode were carefully evaluated. Compared to Fe3O4-LIBs, Fe3O4/G-LIBs exhibited prominently enhanced performance and a reversible specific capacity of 900 mAh g−1 after 5 cycles at 100 and 490 mAh g−1 after 5 cycles at 800 mA g−1. The improved cyclic stability and enhanced rate capability were also obtained.

Super-paramagnetic nano-architecture and its tunable removal efficiency for organic pollutants

In this work, super-paramagnetic nano-architecture was designed to remove the organic pollutants effectively from the waste water. The nano-architectures are composed of super-paramagnetic Fe3O4 hollow spheres, conductive polymer and graphene sheets (RGO) to form binary and ternary nano-architectures. They could be magnetically separated and well-distributed into wastewater again for recycle use. Due to the special function of PPy shell, the binary Fe3O4@PPy core-shell structure exhibits pH-responsive removal efficiency for organic pollutants. Assembling the Fe3O4@PPy core-shell material with RGO sheets could largely improve their surface area, pore volume, and enhance their chemical stability in acid and alkaline solution. Therefore, the Fe3O4@PPy@RGO ternary nano-adsorbents could show favorable and robust removal performance for organic pollutants no matter in neutral, acidic and alkaline environment.

Tribological performance and thermal conductivity of graphene–Fe3O4/poly(phenol-formaldehyde resin) hybrid reinforced carbon fiber composites

Poly(phenol-formaldehyde resin)/carbon fiber composites with different ratios of graphene–Fe3O4 were manufactured through a molding press process.

Enhanced Analytical Performance of Paper Microfluidic Devices by Using Fe3O4 Nanoparticles, MWCNT, and Graphene Oxide.

Spheres, tubes, and planar-shaped nanomaterials as Fe3O4 nanoparticles (MNPs), multiwalled carbon nanotubes (MWCNT), and graphene oxide (GO) were used for the first time to treat microfluidic paper-based analytical devices (μPADs) and create a biocompatible layer with high catalytic surface. Once glucose measurements are critical for diabetes or glycosuria detection and monitoring, the analytical performance of the proposed devices was studied by using bienzymatic colorimetric detection of this carbohydrate. The limit of detection values achieved for glucose with μPADs treated with MNPs, MWCNT, and GO were 43, 62, and 18 μM, respectively. The paper surface modification solves problems associated with the lack of homogeneity on color measurements that compromise the sensitivity and detectability levels in clinical diagnosis.

Electromagnetic response of magnetic graphene hybrid fillers and their evolutionary behaviors

To understand the principles and mechanisms of the graphene-based electromagnetic response composites, we prepare magnetic graphene–Fe3O4 (G–F) hybrid materials and study the electromagnetic properties in the frequency region of 2–18 GHz. The introduction of Fe3O4 nanoparticles is found to play a dominant role in the complex permittivity, resulting in changing the surface polarization and interfacial resistivity of the graphene-based fillers. These influences have been found to greatly impact the corresponding microwave absorption and electromagnetic shielding performance. Owing to the syngeneic effects of G and Fe3O4, the wax-based composites with G–F presented effective microwave absorption ( 20 dB) in the investigated region. The associated mechanisms based on tuning the electromagnetic response of the graphene-based composites via the unique Fe3O4 interfaces have been intensively discussed, which promises great guidance in rationally designing and fabricating advanced graphene-based electromagnetic response materials.

Comparative evaluation of magnetite–graphene oxide and magnetite-reduced graphene oxide composite for As(III) and As(V) removal

Arsenic removal using Fe3O4–graphene oxide composite (M-GO) and Fe3O4-reduced graphene oxide composite (M-rGO) was investigated. The M-GO was more effective to adsorb both As(III) and As(V) than M-rGO, because the more functional groups existing on the M-GO could lead to synthesize more Fe3O4 with M-GO. As(III) was more favorable to be adsorbed than As(V) onto both M-GO and M-rGO. According to the effect of pH on arsenic removal, the electrostatic interaction between the positively charged surface of Fe3O4–graphene based adsorbents and anionic As(V) species was a major factor to adsorb As(V). The adsorption mechanism of As(III), on the other hand, was strongly affected by a surface complexation, rather than electrostatic interactions. Consequently, in terms of the process energy consumption, energy saving could be achieved via omitting the reduction process to fabricate M-rGO from M-GO and the pre-oxidation process to convert As(III) to As(V).

Difunctional Graphene–Fe3O4 Hybrid Nanosheet/Polydimethylsiloxane Nanocomposites with High Positive Piezoresistive and Superparamagnetism Properties as Flexible Touch Sensors

Functional materials with excellent electrical and magnetic properties have a potential application in most high‐tech fields. Here, superparamagnetic graphene–Fe3O4 (G–F) nanosheet hybrids are prepared by a facile one‐step hydrothermal process, which will beneficial to well combine with various polymer matrix to get binary functional composites. Polydimethylsiloxane (PDMS) nanocomposites filled with G–F nanosheets are prepared by a three rolling method. The microstructures of G–F nanosheets as well as the electrical, piezoresistive, and magnetic properties of the G–F/PDMS nanocomposites are investigated. Slightly above the percolation threshold ( fc = 3.4 wt%), the G–F/PDMS nanocomposites with 3.65 wt% of G–F nanosheets show a high conductivity, which is about 10 orders of magnitudes higher than that of pure PDMS, showing an obvious insulator–semiconductor transition. Moreover, the resistance of the nanocomposites with G–F filler near the percolation threshold exponentially increases with the uniaxial pressure. The normalized resistance (R/R0) can reach up to 870 at 0.88 MPa with 3.65 wt% G–F nanosheets loading. The G–F/PDMS nanocomposites also show superparamagnetism with saturation magnetization values of 0.21 emu g−1. These results suggest that the G–F/PDMS nanocomposites in this work provide a new route to fabricate difunctional polymer‐based nanocomposites with a potential application as flexible touch sensors.

Self-assembled three-dimensional graphene/Fe3O4 hydrogel for efficient pollutant adsorption and electromagnetic wave absorption

3D composite hydrogels composed of graphene sheets and Fe3O4 nanoparticles (G/Fe3O4) were prepared via a simple hydrothermal method. The composite has an interconnected 3D porous network, and the Fe3O4 nanoparticles with the size of ∼13nm are uniformly dispersed onto the graphene sheets. Due to the synergistic effects of the assembled graphene sheets and Fe3O4 nanoparticles, the resultant G/Fe3O4 exhibited efficient adsorption for organic pollutant using Rhodamine B as the adsorbate and electromagnetic wave absorption. The maximum removal ratio of Rhodamine B was 99.6%, and the G/Fe3O4 hydrogel demonstrated wide and strong wave absorption achieved in the frequency range of 2–20GHz. Present work shows a way to design and prepare lightweight and high performance materials for both electromagnetic wave absorption and wastewater treatment based on 3D graphene and Fe3O4 nanomaterials.

Amino-functionalized Fe3O4–graphene oxide nanocomposite as magnetic solid-phase extraction adsorbent combined with flame atomic absorption spectrometry for copper analysis in food samples

A new amino-functionalized Fe3O4–graphene oxide nanocomposite (AF-Fe3O4–GO) was synthesized. The properties were characterized by Fourier-transform infrared spectrometry and scanning electron microscopy. The obtained adsorption results showed that the AF-Fe3O4–GO had great adsorptive ability toward Cu(II). Based on these, an effective magnetic solid-phase extraction (MSPE) procedure coupled with flame atomic absorption spectrometry for the pre-concentration and determination of Cu(II) in food samples was developed. Various experimental parameters that could affect the extraction efficiency were investigated in detail. Under optimum conditions, enhancement factor of the method for Cu(II) was found to be 95.08. The proposed method was successfully applied for the analysis of food samples with recoveries ranging from 97.2 to 99.1 % and a correlation coefficient (R 2) of 0.999. Good linearity was obtained, ranging from 1 to 100 µg L−1. The limit of detection and precision of the method were 0.9 ng mL−1 and 1.23 %, respectively. It was confirmed that AF-Fe3O4–GO nanocomposite can be a highly effective MSPE adsorbent used for trace Cu(II) analyses.

A nanocomposite consisting of graphene oxide and Fe3O4 magnetic nanoparticles for the extraction of flavonoids from tea, wine and urine samples

We describe a single-step solvothermal method for the preparation of nanocomposites consisting of graphene oxide and Fe3O4 nanoparticles (GO/Fe3O4). This material is shown to be useful as a magnetic sorbent for the extraction of flavonoids from green tea, red wine, and urine samples. The nanocomposite is taking advantage of the high surface area of GO and the magnetic phase separation feature of the magnetic sorbent. The nanocomposite is recyclable and was applied to the extraction of flavonoids prior to their determination by HPLC. The effects of amount of surfactant, pH value of the sample solution, extraction time, and desorption condition on the extraction efficiency, and the regeneration conditions were optimized. The limits of detection for luteolin, quercetin and kaempferol range from 0.2 to 0.5 ng∙ mL−1 in urine, from 3.0 to 6.0 ng∙mL−1 in green tea, and from 1.0 to 2.5 ng∙mL−1 in red wine. The recoveries are between 82.0 and 101.4 %, with relative standard deviations of <9.3 %.