Narrow Results

Iron silver oxide (Ag_x${\text{Fe}}_{2-x}$O₃; $0<x<2$) structure for photoelectrochemical (PEC) water splitting was grown by RF–DC co-sputtering of an iron–silver target in argon/oxygen plasma mixtures at 300°C, followed by thermal annealing at 560°C. The chemical composition and structure of the deposited film can be tuned by controlling the metal doping and the annealing temperature. The thermal treatment extensively improves the PEC water-splitting performances of the films. XRD patterns of Ag_xFe${}_{2-x}$O₃ shown in the figure can be indexed to the hexagonal structure of silver oxide and the rhombohedral structure of hematite and new X-ray Diffraction (XRD) peaks of Ag_xFe${}_{2-x}$O₃ structure. The annealing and doping process seems to cause a serious change in the crystal structure of the thin film, it showed a serious change in its electrical properties. The electrical parameters of resistance for thin films were measured using the Hall measurement method at room temperature. With Hall measurements, the n-type carrier concentration of the Fe₂O₃ structure was calculated, and it was observed that its resistance was 1M$\mathrm{\Omega }$. Likewise, it was observed that Ag_xFe${}_{2-x}$O₃ exhibited an n-type carrier concentration, and its resistance was calculated to be 0.5M$\mathrm{\Omega }$. The conductivity change is based on silver doping. The doping process seems to cause a change in the bandgap of the thin film, it showed a change in its optical properties. The film’s optical absorption was measured by UV–Vis photo spectroscopy. Subsequently, the structural and topographic properties of Ag_xFe${}_{2-x}$O₃ structures were investigated by high-precision characterization devices.

In this study, forming limit diagrams (FLDs), fracture toughness (FT), mechanical, magnetic, and electro-physical properties of Al/Fe₂O₃ composites have been investigated experimentally. Accumulative-roll-bonding (ARB) process was used to manufacture composite samples. Then, Al/Fe₂O₃ composites have been produced at 300^∘C up to eight ARB passes. Also, magnetic composites have been fabricated with 0, 5% and 10wt.% of particles. The interlayer bonding quality was improved at higher passes. By studying the SEM rapture morphology, it was shown that the rapture mode changed to shear ductile for samples with more passes. For composite samples fabricated at higher passes and in comparison with the annealed sample, elongated dimples were turned to shallow dimples. FLDs area as the main forming criterion dropped severely after pass one and then began to improve at higher passes. Fracture test results showed that after the 8th pass, the value of FT improved gradually to the maximum value of 34.3MPam${}^{1∕2}$.

We have studied the effect of applying an external magnetic field on the characteristics of iron oxide (IO) nanoparticles (NPs) synthesized by pulsed laser ablation in dimethylformamide (DMF). The NPs synthesized with and without applying of magnetic field were characterized by Fourier transformation infrared spectroscopy (FT-IR), UV–Vis absorption, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray diffraction (XRD). SEM results confirmed that the particle size was decreased after applying magnetic field.

The crystal structure and atomic dynamics of Fe₃O₄ nanoparticles have been studied. The crystal structure of iron oxide nanoparticles was determined by X-ray diffraction. The analysis showed that the crystal structure of $d\approx$ 50–100 nm dimensional iron oxide corresponds to a high symmetry cubic crystal structure. Calculations have shown that there are four infrared active, five Raman active and seven hyper-Raman active modes in the space group Fd-3m with cubic symmetry. Four of these modes have been observed using Raman spectroscopy: 213, 271, 380 and 591 cm${}^{-1}$. The vibrational modes are interpreted by Gaussian function. It was found that these vibration modes correspond to the vibration of O–Fe–O bonds and iron-oxygen polyhedra.

Iron oxide (FeO) nanoparticles have gained considerable interest from researchers over the past few decades and have a massive effect on wave absorption materials, magnetic fluid, adsorbent, and a variety of industrial applications. In this study, ferric nitrate, sodium hydroxide, and ammonium hydroxide coalesced to form FeO nanoparticles using the chemical co-precipitation approach. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), UV-VIS analysis, Photoluminesence (PL) spectrum analysis, and electrochemical measurements were used to characterize FeO nanoparticles. As per XRD, the sample’s crystallite size was 22.63nm and 22.64nm after it was annealed at 300^∘C and 400^∘C, respectively. Utilizing XRD, the diffraction patterns were seen. The particles appear to have a fine surface and smooth shape, as seen by SEM photographs. For the detection of FeO nanoparticles, optical and electrochemical examinations were carried out.

The importance of Methanol can be guessed from its usage as in the preparation of methyl tertiary butyl ether (MTBE) fuel, ascetic acid, formaldehyde, metabolize food, biodiesel, pharmaceutical ingredients and products, energy related applications and many more. In this research work, we numerically analyze the impact of temperature-dependent viscosity on flow and heat transfer of Methanol Iron oxide, CH₃OH–Fe₃O₄ nanofluid through annular sector duct. The effects of pertinent parameters corresponding to temperature-dependent viscosity, m, Fe₃O₄ nanoparticles’ contribution, n and geometrical configuration (i.e. $\widehat{R}$ and N), are revealed graphically by velocity contours, isotherms, velocity and temperature profiles, and discussed physically. Both parameters m and n suppress the velocity and temperature profiles by increasing the friction factor $f\mathrm{\text{Re}}$ and average Nusselt number $\mathrm{\text{Nu}}$. Same impacts of m and n have been observed for all values of $\widehat{R}$ and N.

Pre-annealing as part of a two-step thermal oxidation process has a significant effect on the growth of hematite ($\alpha$-Fe₂O₃) nanowires on Fe foil. High-density aligned nanowires were obtained on iron foils pre-annealed at 300${}^{\circ }$C under a dry air flow for 30min. The X-ray diffraction (XRD) patterns indicate that the nanowires are transformed from the small $\alpha$-Fe₂O₃ grains and uniquely grow in the (110) direction. The formation of a high-density of small grains by pre-annealing improved the alignment and density of the $\alpha$-Fe₂O₃ nanowires.

Titanium dioxide (TiO₂) and iron oxide (Fe₂O₃) nanoparticles (NPs) were successfully deposited on multiwall carbon nanotubes (MWCNTs) films using a low-cost and simple sparking process. The as-deposited film was annealed at $350^{\circ }$C for 2h to improve their crystallinity. The results show the anatase TiO₂ and hematite Fe₂O₃ NPs with the size of 5–10nm are coated on MWCNTs. The bandgap energy of the as-prepared and the annealed films were 2.3eV and 2.7eV. Photocatalytic activity of the annealed films under visible irradiation is greater than the as-prepared films. Moreover, TiO₂:Fe₂O₃ with the ratio of 3:1 was the optimized condition. Interestingly, the relative current of the annealed films increased to 0.75 when increasing the irradiation time for 5h. This result confirmed that the excited electron from photocatalytic activity can be transferred through the MWCNTs. This is an alternative way to produce the electric current from photocatalysis in the future.

High-quality hydrophobic or hydrophilic ferrofluid based on magnetite (Fe₃O₄) nanoparticles can be synthesized by one-pot direct synthesis which involves thermolysis of Iron(III) acetylacetonate, Fe(acac)₃ in hydrophobic or hydrophilic stabilizing agent, respectively. The structure of the nanoparticles dispersed in the ferrofluid was studied using XRD, FTIR, XPS, and TGA analysis, while morphology and size of the nanoparticles were determined by TEM. The magnetic properties of the samples were measured using VSM and SQUID measurement. The results show that oleylamine (OM) and tri(ethylene glycol) (TREG) coated Fe₃O₄ nanoparticles which are well stabilized in hydrophobic and hydrophilic ferrofluid, respectively, are relatively monodisperse, single crystalline and superparamagnetic in nature with the blocking temperature at around 100 K.

Here, we report single step synthesis of hydrophobic and hydrophilic Fe₃O₄, ZnO, CoO and Y₂O₃:Eu nanoparticles via thermal decomposition of different organometallic complexes in oleylamine (OM) and tri(ethyleneglycol) (TREG) media, respectively. The crystal structure of the as-prepared nanoparticles is identified using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Morphology of the nanoparticles is determined by transmission electron microscopy (TEM) while the magnetic properties are measured using vibrating sample magnetometer (VSM). Thermolysis of appropriate precursors in OM and TREG medium are very capable of producing the highly dispresed hydrophobic and hydrophilic nanoparticles with diverse morphologies.

This paper analyzes the effects of additives on the properties of Iron oxide. The Iron oxide was synthesized using the co-precipitation method. The X-ray diffraction (XRD) peaks of resultant Iron oxide perfectly matched with JCPDS #860550 ($\alpha$ phase of Iron oxide / Hematite). The additives like Cobalt oxide, Nickel metal, Indium oxide and Tin metal with diverse properties procured in readymade forms were mechanically mixed with Iron oxide in 1:99, 3:97, 5:95 and 7:93 weight ratios, respectively. The XRD peaks for additives were prominent for 7:93 (Additive: Base Material) weight % ratio samples. Therefore, for further studies, only these samples were used. In this study, variations in XRD intensity, lattice parameters, unit cell volume, grain size, micro-strains (W-H analysis), dislocation density and stacking fault probability were analyzed. The specific surface area of particles was calculated by scanning electron microscope analysis. The presence of additives was also confirmed by energy dispersive spectra (EDS). The M-H loops (Vibrating Sample Magnetometer analysis) for samples under investigation showed rare vertical shifts. The weak magnetic behavior of bare Hematite (1.0 emu/gm) sample improved to antiferromagnetic behavior due to the addition of Cobalt oxide (7.89 emu/gm) and Nickel metal (2.76 emu/gm). The addition of Indium oxide (0.65 emu/gm) and Tin metal (0.73 emu/gm) samples showed a decreased magnetic saturation.

Using trirutile-structure layered tantalum–tungsten acid as the layered host, $n$-propylamin as the pre-swelling agent and aqueous solution of [Fe₃(CH₃COO)₇(OH)(H₂O)]NO₃ as the pillaring solution, oligomeric polyhydroxyacetato-Fe(III) species-intercalated layered HTaWO₆ was synthesized by a stepwise ion-exchange way at room temperature. Upon calcining at 673K in air atmosphere, iron oxide-pillared layered HTaWO₆with nanoscale interlayer distance (denoted as Fe₂O₃-HTaWO${}_6)$ was obtained. A series of Fe₂O₃-HTaWO₆ samples with various Fe contents were prepared by using different volume of Fe(III)-pillaring solution. The layered intermediates obtained at each stage of the ions-exchange process and the final layered products were characterized by powder XRD, FT-IR, DR UV-Vis and SEM techniques. The photocatalytic performance of the Fe₂O₃-pillared layered HTaWO₆ samples for degradation of rhodamine B was investigated. Compared with un-pillared layered HTaWO₆, the Fe₂O₃-pillared layered HTaWO₆ exhibited a significantly-improved photo-absorption performance and an enhanced photocatalytic activity. The Fe₂O₃-HTaWO₆ sample with 5.8% (wt) iron showed the best catalytic performance in the photodegradation reaction of rhodamine B.

The purpose of this study is to evaluate the structure, morphology and optical properties of a newly developed hybrid structure that was generated from a Fe₂O₃–Cu–PVA composite matrix. Several methods, such as field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), as well as absorption and transmission spectra, were used to investigate the samples. The addition of copper was found to have no influence on the crystalline arrangement of PVA–Fe₂O₃, according to the findings of crystallography. In the wavelength region from 450nm to 550 nm, the produced composites exhibit significant absorption. It is essential that the region of shorter wavelengths experiences a steady shift toward the region of maximum absorption in these composites when copper is included. The transmittance of PVA–Fe₂O₃ is over 80% in the region of 600–800nm, making it an extremely transparent material. Following the addition of 5% by weight of copper to the nanocomposite, the transmittance of the material dropped to 50% within the same range of wavelengths. The synthesized materials were put to use as anti-cancer cells, and they demonstrated a high level of effectiveness in the process of killing tumor cells, particularly the PVA–Fe₂O₃–Cu combination.

The synthesis of nanosized beads of superparamagnetic iron oxide nanoparticles coated with 3-(aminopropyl)triethoxysilane is reported in this paper. The resulting beads are agglomerates of SPIONs with an open fractal like structure. These beads have been examined by means of transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and attenuated total reflection Fourier transformation infrared spectroscopy (ATR-FTIR). The resulting beads with a size of 88 nm have been further biofunctionalized with avidin and biotinylated oligo(dT).

The pollution of water due to the release of heavy metals are particularly problematic and supplies of clean water have become a major problem worldwide. The heavy metal ions can cause toxicities and serious side effects toward human health; therefore, these metal ions should be removed from water and wastewater. A variety of strategies have been developed for efficient heavy metal removal from waters. Adsorption/ion exchange strategy play a great important role in removing heavy metal ions due to their advantages. Nanomaterials are excellent adsorbents and extensive studies have been performed to remove heavy metals from wastewater by developing and using various nanomaterials. Recent developments for the heavy metals removal by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials in batch and flow systems are described in this review.

Magnetic and fluorescent-based sensors have demonstrated widely applications due to their easily recycle and quickly optical response. However, the complex synthesis and weaker function of these sensors limit their practical applications. Herein, an unmodified, magnetic-functionalized carbon dots-based fluorescent sensor has been developed for label-free detection of pH and Cu${}^{2+}$ with high sensitivity. The sensors can not only reversibly quench and recover the fluorescence signals in response to the variation of surrounding environment including pH and Cu${}^{2+}$, but also be used as a high-efficiency recyclable adsorbent for removing Cu${}^{2+}$, Hg${}^{2+}$, Cr${}^{3+}$ and Pb${}^{2+}$ from aqueous solution.

We constructed a multifunctional (Fe₃O₄/nGO)@mSiO₂/GQDs drug carrier for loading and microwave-controlled release of an etoposide (VP16) as the anticancer drug. This nanocomposite consisted of magnetic core Fe₃O₄, microwave-absorbing nanographene oxide (nGO), fluorescent graphene quantum dots (GQDs) and intermediate barrier layer (mesoporous silica). It has a large surface area of 359.8m²/g, excellent fluorescence emission and ample magnetic performance of 36.00emu/g. After microwave irradiation for 140 s, the temperature of (Fe₃O₄/nGO)@mSiO₂/GQDs nanoparticles rapidly went up to 90^∘C. The loading rate of VP16 was as high as 68%, the release rate reached 87% within 280min under microwave irradiation. Therefore, the functionalized (Fe₃O₄/nGO)@mSiO₂/GQDs nanoparticles will have potential application for clinical treatment as drug delivery system.

Highly ordered mesoporous iron oxide (α-Fe₂O₃) material has been successfully obtained from mesoporous silica template, KIT-6 (3-D Cubic Ia3d symmetry), through nano-replication method. The mesoporous α-Fe₂O₃ material thus obtained exhibits well-defined mesopores (2.7 nm in diameter), high surface area (148 m²/g), high pore volume (0.47 cm³/g) and crystalline frameworks. The morphology of the mesoporous α-Fe₂O₃ material is very uniform in spherical shape of which the average particle size is about 100 nm in diameter.

Monodispersed magnetite (Fe₃O₄) nanoparticles can be synthesized by thermal decomposition of iron(III) acetylacetonate, Fe(acac)₃. High saturation magnetization M_S of the magnetite particles is extremely important to realize the full potential of magnetite materials in biomedical application. In this work, we have studied the different effects (time, temperature and surfactant) on structure and magnetic properties of Fe₃O₄ nanoparticles. The M_S of the particles are enhanced after the synthesis at a higher reaction temperature and/or a longer reaction time. However, the increase in reaction temperature and/or reaction time resulted in particle size increase and the broadening of the particle size distribution. In this work, high M_S value of the magnetite particles has been achieved through adopting surfactant or modification of solvent to overcome the temperature and time effects, while the smaller size particles with an acceptable size distribution has been maintained. Size and morphology of the particles were studied by TEM while magnetic properties of the particles were measured using VSM. The saturation magnetization M_S of the particles can be increased at higher reaction temperature and/or longer reaction time, while narrow size distribution of the particles can be maintained either by the selective adsorption of oleic acid to the particle surface or by synthesizing them using solvent free thermal decomposition reaction.

Fulvic acid coated Fe₃O₄ superparamagnetic nanoparticles were synthesized by a coprecipitation technique with iron salts and a small molecule stabilizer-fulvic acid. The prepared nanoparticles were well dispersed in water with about 10 nm in size according to transmission electron microscopy (TEM) observations. Fourier transform infrared spectroscopy (FTIR) revealed that fulvic acid were successfully covalently bonded to Fe₃O₄ through the two adjacent phenolic hydroxyl groups and the carboxyl (-COOH) groups were functionalized to the surface. The vibrating sample magnetometer (VSM) result showed that the nanoparticles were superparamagnetic and the saturation magnetizations were 60 emu/g. Moreover, their efficacy of liver magnetic resonance imaging (MRI) contrast agent was investigated by using live rat and tumor-bearing rabbit models through conventional clinical 1.5T MRI.