Facile Synthesis of FeCo/Fe3O4 Nanocomposite with High Wave-Absorbing Properties

The FeCo/Fe₃O₄ nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe₃O₄ are formed by one step. The structure of the FeCo/Fe₃O₄ nanocomposite was characterized by means of Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectrometer spectroscopy (EDX). They show that the mass ratio of FeCo/Fe₃O₄ strongly depends on the reaction temperature. Such various architectures follow a stepwise growth mechanism of the composites prepared in various reaction temperatures were also discussed. It indicates that this strategy is facile, effective and controllable for the synthesis of FeCo/Fe₃O₄ by the one-step method. Furthermore, the magnetic and wave-absorbing properties of the nanocomposites with various structures were investigated in detail. The results show that the FeCo/Fe₃O₄ with higher mass ratio has higher magnetic properties. Moreover, the FeCo/Fe₃O₄ nanocomposite shows high wave-absorbing properties (e.g., −37.9 dB), which are expected to apply in microwave absorbing materials.     

Influence of Fe3O4 nanoparticles decoration on dye adsorption and magnetic separation properties of Fe3O4/rGO nanocomposites

Magnetite (Fe₃O₄) nanoparticles were prepared by solvothermal method and its composites with reduced graphene oxide namely FG1, FG2, and FG3 (changing magnetite precursor loading 0.1, 0.5, and 1 respectively) were used as adsorbents for the removal of methyl violet (MV) dye. The structural and morphological results confirm that rGO sheets were decorated with Fe₃O₄ and it ensures the variation of active sites toward dye removal property. The maximum adsorption capacity obtained for FG2 was 196 mg/g. The adsorption isotherms and kinetics better fit Langmuir and pseudo-second-order kinetic model for FG1 and FG2. Increasing of Fe₃O₄ loading on rGO reduces the dye adsorption sites and too low Fe₃O₄ loading affects the magnetic separation. The optimal loading of Fe₃O₄ on rGO is important parameter for the adsorption process and fast separation of adsorbent.     

Hydrothermal synthesis of Co3O4 nanosheets and its application in photoelectrochemical water splitting

In this study, Co₃O₄ nanosheets were synthesized through hydrothermal method using cobalt nitrate hexahydrate. X-ray diffraction, diffuse reflectance spectra, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy were applied to investigate the properties of as-synthesized samples. Ultimately, the electrochemical and photoelectrochemical properties were evaluated by Mott–Schottky analysis and measuring photoconversion efficiency of Co₃O₄ nanosheets. The results indicated that Co₃O₄ nanosheets exhibited a maximum efficiency of 0.92% for water electrolysis under simulated 1.5 global sunlight air mass, which further suggests the excellent potential of Co₃O₄ nanosheets for application in hydrogen generation through photocatalytic water splitting.     

Enhanced removal of lead and cadmium from water by Fe3O4-cross linked-O-phenylenediamine nano-composite

A method is presented for surface encapsulation of nano-Fe₃O₄ by o-phenylenediamine via cross-linking using formaldehyde and glutaraldhyde for the formation of two newly designed magnetic nano-sorbents. These have been characterized by FT-IR, TGA, and SEM and maintained the magnetic and thermal stability characters. The metal capacity values of Pb(II) and Cd(II) have been optimized in presence of different physico-chemical parameters and confirmed the superior selectivity for Pb(II). Maximum capacity values of Pb(II) (7000-10000 ± 250-675 µmol g^?1) and Cd(II) (1500-2250 ± 30-75 µmol g^?1) at optimum conditions and excellent extraction values (94.10-100.0 ± 1.2-3.5%) from industrial wastewater have been identified.     

Preparation and property characterization of PAA/Fe3O4 nanocomposite

PAA/Fe₃O₄ nanocomposites were prepared by mixing nano-Fe₃O₄ and polyacrylic acid (PAA) ethanol solution and then evaporating the solvent. The materials were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscope (FTIR), thermogravimetry analysis (TGA), dynamic ultra-micro hardness tester (DUMHT) and superconducting quantum interference device (SQUID) magnetometer. Results showed that PAA coordinated with nano-Fe₃O₄ to form a cross-linking structure. The presence of nano-Fe₃O₄ enhanced the thermal stability of the nanocomposite. The elasticity and hardness of the nanocomposite increased, and the indentation depth reduced with the increase of Fe₃O₄ content in the composites. The nanocomposites showed superparamagnetic properties at 300 K. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(5): 47–50 [译自: 中山大学学报 (自然科学版)]     

Platanus orientalis leaves based hierarchical porous carbon microspheres as high efficiency adsorbents for organic dyes removal

Water contamination caused by hazardous organic dyes has drawn considerable attention, among all of the techniques released, adsorption has been widely used, which however to a large degree is dependent on the development of high efficiency adsorbents. Waste biomass based porous carbon is becoming the new star class of adsorbents, and thus contribute more to the sustainable development of the society. In this work, for the first time to the best of our knowledge, abundant waste fallen Platanus orientalis leaves are employed as the raw material for hierarchical activated porous carbon(APC) microspheres via a mild hydrothermal carbonization(210 °C,12.0 h) followed by one-step calcination(750 °C, 1.0 h). The APC microspheres exhibit a specific surface area of1355.53 m~2·g~(-1) and abundant functional groups such as O—H and C=O. Furthermore, the APC microspheres are used as the adsorbents for removal of Rh B and MO, with the maximum adsorption capabilities of 557.06 mg·g~(-1) and 327.49 mg·g~(-1), respectively, higher than those of the most porous carbon originated from biomass. The adsorption rates rapidly approach to 98.2%(Rh B) and 95.4%(MO) within 10 min. The adsorption data can be well fitted by Langmuir isotherm model and the pseudo-second-order kinetic model, meanwhile the intra-particle diffusion and Boyd models simultaneously indicate that the diffusion within the pores is the main rate-limiting step. Besides, the APC microspheres also demonstrate good recyclability, and may also be applied to other areas such as heterogeneous catalysis and energy storage.     

Efficient solar photocatalyst based on cobalt oxide/iron oxide composite nanofibers for the detoxification of organic pollutants

A Co₃O₄/Fe₂O₃ composite nanofiber-based solar photocatalyst has been prepared, and its catalytic performance was evaluated by degrading acridine orange (AO) and brilliant cresyl blue (BCB) beneath solar light. The morphological and physiochemical structure of the synthesized solar photocatalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). FESEM indicates that the Co₃O₄/Fe₂O₃ composite has fiber-like nanostructures with an average diameter of approximately 20 nm. These nanofibers are made of aggregated nanoparticles having approximately 8.0 nm of average diameter. The optical properties were examined by UV-visible spectrophotometry, and the band gap of the solar photocatalyst was found to be 2.12 eV. The as-grown solar photocatalyst exhibited high catalytic degradation in a short time by applying to degrade AO and BCB. The pH had an effect on the catalytic performance of the as-grown solar photocatalyst, and it was found that the synthesized solar photocatalyst is more efficient at high pH. The kinetics study of both AO and BCB degradation indicates that the as-grown nanocatalyst would be a talented and efficient solar photocatalyst for the removal of hazardous and toxic organic materials.     

Hydrothermal preparation of octadecahedron Fe3O4 thin film for use in an electrochemical supercapacitor

A Fe₃O₄ film with regularly edge-affected cubic (octadecahedron) morphology was successfully prepared on stainless steel foil by a simple and benign hydrothermal process. The potential for the use of the film in a supercapacitor was tested by investigating the electrochemical behavior of the Fe₃O₄ film using cyclic voltammetry (CV) and galvanostatic charge/discharge tests. The Fe₃O₄ film showed a CV indicative of a typical pseudocapactive behavior in 1 mol L⁻¹ Na₂SO₃ solution. Furthermore, this film exhibited a specific capacitance of 118.2 F g⁻¹ at the current of 6 mA between −1 and 0.1 V with a capacity retention of 88.75% after 500 cycles.     

Preparation of hollow porous Cu2O microspheres and photocatalytic activity under visible light irradiation

Cu₂O p-type semiconductor hollow porous microspheres have been prepared by using a simple soft-template method at room temperature. The morphology of as-synthesized samples is hollow spherical structures with the diameter ranging from 200 to 500 nm, and the surfaces of the spheres are rough, porous and with lots of channels and folds. The photocatalytic activity of degradation of methyl orange (MO) under visible light irradiation was investigated by UV-visible spectroscopy. The results show that the hollow porous Cu₂O particles were uniform in diameters and have an excellent ability in visible light-induced degradation of MO. Meanwhile, the growth mechanism of the prepared Cu₂O was also analyzed. We find that sodium dodecyl sulfate acted the role of soft templates in the synthesis process. The hollow porous structure was not only sensitive to the soft template but also to the amount of reagents.     

A novel method for the synthesis of Fe3O4 nanoparticles/CdS nanowires heterostructure nanocomposite and uses in photodegradation of methylene blue

We report here a simple, efficient, practical, and novel method for the preparation of Fe₃O₄ nanoparticles (NPs)/CdS nanowires. The CdS nanowire/Fe₃O₄ NP reported here was characterized by transmission electron microscopy (TEM), X-ray Diffraction (XRD), vibrating sample magnetometer (VSM), and energy-dispersive X-ray. Cadmium diethyl dithiophosphate has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality one-dimensional Fe₃O₄ NPs/CdS nanowires using a simple hydrothermal method in the presence of Fe₃O₄ NPs in water. Photocatalytic activity studies show that the nanocomposite has good photocatalytic activity toward the photodegradation of methylene blue in an aqueous solution.     

Synthesis of new electromagnetic nanocomposite based on modified Fe3O4 nanoparticles with enhanced magnetic,conductive, and catalytic properties

A new method for the fabrication of an electromagnetic nanocomposite based on Fe₃O₄ and polyaniline (PANI) is offered. The authors focused on improvement of the physical and electromagnetic properties of the nanocomposite using a new synthetic method. Supermagnetic Fe₃O₄ nanoparticles were synthesized through coprecipitation method. As a chemical modification, the third generation of poly (amidoamine) dendrimer was grafted on the surface of the nanoparticles. PANI was grafted from –NH₂ functional groups of dendrimer via in situ polymerization of aniline. Finally, Au nanoparticles were loaded on the nanocomposite and its catalytic activity for reduction reactions was studied.     

Fe3O4 Nanozymes Improve Neuroblast Differentiation and Blood-Brain Barrier Integrity of the Hippocampal Dentate Gyrus in D-Galactose-Induced Aged Mice

Aging is a process associated with blood–brain barrier (BBB) damage and the reduction in neurogenesis, and is the greatest known risk factor for neurodegenerative disorders. However, the effects of Fe₃O₄ nanozymes on neurogenesis have rarely been studied. This study examined the effects of Fe₃O₄ nanozymes on neuronal differentiation in the dentate gyrus (DG) and BBB integrity of D-galactose-induced aged mice. Long-term treatment with Fe₃O₄ nanozymes (10 μg/mL diluted in ddH₂O daily) markedly increased the doublecortin (DCX) immunoreactivity and decreased BBB injury induced by D-galactose treatment. In addition, the decreases in the levels of antioxidant proteins including superoxide dismutase (SOD) and catalase as well as autophagy-related proteins such as Becin-1, LC3II/I, and Atg7 induced by D-galactose treatment were significantly ameliorated by Fe₃O₄ nanozymes in the DG of the mouse hippocampus. Furthermore, Fe₃O₄ nanozyme treatment showed an inhibitory effect against apoptosis in the hippocampus. In conclusion, Fe₃O₄ nanozymes can relieve neuroblast damage and promote neuroblast differentiation in the hippocampal DG by regulating oxidative stress, apoptosis, and autophagy.     

Influence of Co3O4, Fe2O3 and SiC on microstructure and properties of glass foam from waste cathode ray tube display panel (CRT)

Abstract

In the present study, the effect of temperature and oxidising agents such as Fe₂O₃ and Co₃O₄ on physical and mechanical properties of glass foam is investigated. The glass foam is made of panel glass from dismantled cathode ray tubes and SiC as a foaming agent. In the process, powdered waste glass (mean particle size below 63 μm) in addition to 4 wt-% SiC powder (mean particle size below 45 μm) are combined with Fe₂O₃ and Co₃O₄ (0·4, 0·8 and 1·2 wt-%) have been sintered at 950 and 1050°C. The glass foamed containing 1·2 wt-% Co₃O₄ has good physical properties, with porosity more than 80% and bending strength more than 1·57±0·12 MPa. However, by adding different amounts of Fe₂O₃ in comparison with samples without iron oxide, little changes in porosity and strength are obtained.     

Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

Fe₃O₄/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe₃O₄/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.     

An efficient method for synthesis of some heterocyclic compounds containing 3-iminoisatin and 1,2,4-triazole using Fe3O4 magnetic nanoparticles

1,2,4-triazole derivatives were prepared by reaction of thiocarbohydrazide and some esters in 60% ethanol. Condensation of 1,2,4-triazole derivatives with isatin gave Schiff bases of 3-iminoisatin derivatives. Reaction of malonic or succinic acid dihydrazide with isatin lead to formation of N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)-malonamide 8a and N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)succinamide 8b in good yields under mild reaction conditions. These reactions are catalyzed by Fe₃O₄ MNPs. The chemical structures were confirmed by Fourier transform-infrared, ¹H-NMR, ¹³C-NMR, gas chromatography-mass spectrometry spectroscopy, and elemental analysis.     

Synthesis of MIL-Modified Fe3O4 Magnetic Nanoparticles for Enhancing Uptake and Efficiency of Temozolomide in Glioblastoma Treatment

A nanometric hybrid system consisting of a Fe₃O₄ magnetic nanoparticles modified through the growth of Fe-based Metal-organic frameworks of the MIL (Materials Institute Lavoiser) was developed. The obtained system retains both the nanometer dimensions and the magnetic properties of the Fe₃O₄ nanoparticles and possesses increased the loading capability due to the highly porous Fe-MIL. It was tested to load, carry and release temozolomide (TMZ) for the treatment of glioblastoma multiforme one of the most aggressive and deadly human cancers. The chemical characterization of the hybrid system was performed through various complementary techniques: X-ray-diffraction, thermogravimetric analysis, FT-IR and X-ray photoelectron spectroscopies. The nanomaterial showed low toxicity and an increased adsorption capacity compared to bare Fe₃O₄ magnetic nanoparticles (MNPs). It can load about 12 mg/g of TMZ and carry the drug into A172 cells without degradation. Our experimental data confirm that, after 48 h of treatment, the TMZ-loaded hybrid nanoparticles (15 and 20 μg/mL) suppressed human glioblastoma cell viability much more effectively than the free drug. Finally, we found that the internalization of the MIL-modified system is more evident than bare MNPs at all the used concentrations both in the cytoplasm and in the nucleus suggesting that it can be capable of overcoming the blood-brain barrier and targeting brain tumors. In conclusion, these results indicate that this combined nanoparticle represents a highly promising drug delivery system for TMZ targeting into cancer cells.     

Fabrication of PLA/MWCNT/Fe3O4 composite nanofibers for leukemia cancer cells

The efficient delivery of daunorubicin loaded poly (lactic acid) (PLA)/multiwalled carbon nanotubes (MWCNT)/Fe₃O₄ composite nanofibers was investigated. The synthesized nanofibers were characterized using SEM, TEM, and XRD analysis. The proliferation inhibition effect of PLA/MWCNT/Fe₃O₄ nanofibrous scaffolds on leukemia K562 cell lines was investigated. The effect of nanofiber concentration on the daunorubicin delivery in the absence and presence of external magnetic field was also evaluated. The results indicated that the incorporation of daunorubicin into the prepared nanofibrous scaffold under applied magnetic field could have synergistic cytotoxic effect on leukemia cancer cells. The drug release mechanism followed the non-Fickian transport.     

Three-dimensional hierarchical ZnCo2O4 flower-like microspheres assembled from porous nanosheets: Hydrothermal synthesis and electrochemical properties

In this work, three-dimensional hierarchical ZnCo₂O₄ flower-like microspheres have been synthesized on a large scale via a facile and economical citrate-mediated hydrothermal method followed by an annealing process in air. The as-synthesized ZnCo₂O₄ flower-like microspheres are constructed by numerous interweaving porous nanosheets. According to the experimental results, a formation mechanism involving the assembly of the nanosheets from nanoparticles into flower-like microsphere is proposed. As a virtue of their beneficial structural features, the ZnCo₂O₄ flower-like microspheres exhibit a high lithium storage capacity and excellent cycling stability (1136 mA h g⁻¹ at 100 mA g⁻¹ after 50 cycles). This remarkable electrochemical performance can be ascribed to the hierarchical structure and porous structures in the nanosheets, which effectively increases the contact area between the active materials and the electrolyte, shortening the Li⁺ diffusion pathway and buffering the volume variation during cycling.     

A Novel Yolk–Shell Fe3O4@ Mesoporous Carbon Nanoparticle as an Effective Tumor-Targeting Nanocarrier for Improvement of Chemotherapy and Photothermal Therapy

Owing to their good stability and high photothermal conversion efficiency, the development of carbon-based nanoparticles has been intensively investigated, while the limitation of unsatisfactory cellular internalization impedes their further clinical application. Herein, we report a novel strategy for fabrication of Fe₃O₄ yolk–shell mesoporous carbon nanocarriers (Fe₃O₄@hmC) with monodispersity and uniform size, which presented significantly higher cell membrane adsorption and cellular uptake properties in comparison with common solid silica-supported mesoporous carbon nanoparticles with core–shell structure. Moreover, the MRI performance of this novel Fe-based nanoparticle could facilitate precise tumor diagnosis. More importantly, after DOX loading (Fe₃O₄@hmC-DOX), owing to synergistic effect of chemo–phototherapy, this therapeutic agent exhibited predominant tumor cell ablation capability under 808 nm NIR laser irradiation, both in vitro and in vivo. Our work has laid a solid foundation for therapeutics with hollowed carbon shell for solid tumor diagnosis and therapy in clinical trials.     

Fe3O4@SiO2-SnCl4: An Efficient Catalyst for the Synthesis of Xanthene Derivatives under Ultrasonic Irradiation

Grafting of SnCl₄ on the Fe₃O₄@SiO₂ nanoparticles afforded Fe₃O₄@SiO₂-SnCl₄ as a novel inorganic heterogenous catalyst, which was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), Field Emission Scanning Electron Microscopy (FE-SEM), and transmission electron microscopy (TEM). In this research, we report a convenient and efficient direct protocol for the preparation of xanthene derivatives via condensation of β-naphthol, dimedone, or mixture of β-naphthol and dimedone with various aromatic aldehydes in the presence of the catalytic amount of Fe₃O₄@SiO₂-SnCl₄ under ultrasonic irradiation. This procedure has a lot of advantages such as: very easy reaction conditions, absence of any tedious workup, or purification, and much milder method. The corresponding products have been obtained in excellent yields, high purity, and short reaction times.