Deposition Of Iron Oxide Nanoparticles Research Articles

Direct laser writing of 3D microstructures at solid-liquid interfaces by plasmonic bubbles

Plasmonic microbubbles produced by laser irradiated gold nanoparticles (GNPs) in various liquids have emerged in numerous innovative applications. The nucleation of these bubbles inherently involves rich phenomena. In this paper, we systematically investigate the physicochemical hydrodynamics of plasmonic bubbles upon irradiation of a continuous wave (CW) laser on a GNP decorated sample surface in ferric nitrate solution. Surprisingly, we observe the direct formation of well-defined micro-domes on the sample surface. This reveals that the nucleation of a plasmonic bubble is associated with the solvothermal decomposition of ferric nitrate in the solution. The plasmonic bubble acts as a template for the deposition of iron oxide nanoparticles. It first forms a rim, then a micro-shell, which eventually becomes a solid micro-dome. Experimental results show that the micro-dome radius Rd exhibits an obvious Rd ∝ t1/3 dependence on time t, which can be well interpreted theoretically. Our findings reveal the rich phenomena associated with plasmonic bubble nucleation in a thermally decomposable solution, paving the way for a plasmonic bubble based approach to fabricating three dimensional microstructures using an ordinary CW laser.

Deposition of iron oxide nanoparticles on glass mat using DC magnetron sputtering method-magnetic properties

Magnetic nanoparticles have important applications in industrial textiles and can be used as filters for separating color and heavy metals from factory wastewater. One of the most important magnetic materials is iron oxide(Fe3O4). In this research, different sputtering systems were used for depositing iron oxide nanoparticles on the surface of the glass mat. Three-angle sputtering machine, DC sputtering, and DC magnetron sputtering were used for the deposition of Iron Oxide nanoparticles. Deposition of Iron oxide nanoparticles with three angel and DC sputter systems was not satisfactory, as the rate of sputtering is very low in these machines. Therefore, these two methods were discarded and the study was performed on the next method. The results related to DC magnetron sputtering were satisfactory. The glass mat was deposited by Iron Oxide with different exposure times of 2, 3, and 4 h. The thickness of the layer, structural shape, and existing elements on the surface, were investigated using different analytical instruments. The magnetic properties of deposited fabrics were studied with a vibrating-sample magnetometer (VSM) and photocatalytic properties were also discussed.

Magnetothermally-responsive nanocarriers using confined phosphorylated halloysite nanoreactor for in situ iron oxide nanoparticle synthesis: A MW-assisted solvothermal approach

A family of easily recoverable magnetic and thermally responsive composite materials, with nanoscale dimensions, were synthesized by a rapid and simple solvothermal approach. The synthesis was thermally activated, accelerated, and controlled using a coaxial antenna to directly apply the microwave energy inside the solvothermal reactor. The composite materials were made up by a confined phosphorylated nanoreactor, namely halloysite nanotubes grafted on the inner lumen with phosphoric acid (HNTs-(H+-PO4)), that promoted the urea hydrolysis thus favoring the formation of a local alkaline environment to catalyze the homogeneous in situ precipitation of superparamagnetic iron oxide nanoparticles (IONs) selectively on their inner or outer surface. Two new MW-assisted solvothermal methodologies were used: 1) in the first the solvent is directly loaded into the MW-assisted reactor together with HNTs-(H+-PO4) mechanically preloaded with iron chloride and urea in the lumen 2) in the second the synthesis is preceded by a further pre-functionalization step of the iron salt with clove essential oil (EO) as a green functionalization agent. Structural, morphological, textural, and magnetic properties were assessed by TEM, N2 physisorption, TG-FTIR, ICP, XRD, magnetic and magnetic hyperthermia measurements. The MW-assisted solvothermal deposition of IONs was fully controlled using the phosphorylated nanoreactor, in short synthesis times, by a simple methodology following the principles of sustainable chemistry. IONs were selectively deposited on the outer surface or in the inner lumen of HNTs yielding easily recoverable superparamagnetic and thermally responsive nanocarriers suitable for applications like targeted hyperthermia therapy.

Electrophoretic deposition of iron oxide nanoparticles to achieve thick nickel/iron oxide magnetic nanocomposite films

For modern switching power supplies, current bulk magnetic materials, such as ferrites or magnetic metal alloys, cannot provide both low loss and high magnetic saturation to function with both high power density and high efficiency at high frequencies (10-100 MHz). Magnetic nanocomposites comprised of a ferrite and magnetic metal alloy provide the opportunity to achieve these desired magnetic properties, but previously investigated thin-film fabrication techniques have difficulty achieving multi-micrometer film thicknesses which are necessary to provide practical magnetic energy storage and power handling. Here, we present a versatile technique to fabricate thick magnetic nanocomposites via a two-step process, consisting of the electrophoretic deposition of an iron oxide nanoparticle phase into a mold on a substrate, followed by electro-infiltration of a nickel matrix. The deposited films are imaged via scanning electron microscopy and energy dispersive X-ray spectroscopy to identify the presence of iron and nickel, confirming the infiltration of the nickel between the iron oxide nanoparticles. A film thickness of ∼7 μm was measured via stylus profilometry. Further confirmation of successful composite formation is obtained with vibrating sample magnetometry, showing the saturation magnetization value of the composite (473 kA/m) falls between that of the iron oxide nanoparticles (280 kA/m) and the nickel matrix (555 kA/m). These results demonstrate the potential of electrophoretic deposition coupled with electro-infiltration to fabricate magnetic nanocomposite films.

Surface Functionalization of Polyester Fibers via One-step Green Formation and Assembling of Iron Oxide Nanoparticles with Photo and Magneto Activities

In this research for the first time, surface functionalization of polyester fibers was performed via one-step, facile and clean strategy through green synthesis and deposition of iron oxide nanoparticles for photocatalytic and magnetic applications. The commercial ash of Seidlitzia Rosmarinus plant was used as a natural alkaline source for nanoparticles synthesis as well as surface modification of polyester substrate and iron sulfate as metal precursor. The presence of iron oxide nanoparticles on polyester fibers was proved by X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, mapping, field-emission scanning electron microscope images and Fourier transform infrared spectra. The fabricated samples exhibited very good photocatalytic activities toward methylene blue decoloration about 95.45% after 48 h exposing to sunlight irradiation. In addition, they indicated appropriate magnetic properties with saturated magnetization of 2.30 and 1.69 emu/g at room temperature. The coloring effect, weight change and wettability behavior of the fabricated samples were also investigated. The mentioned route in this paper can simply be scaled up as an eco-friendly and scalable route for surface functionalization of polymeric substrates via synthesis and deposition of iron oxide nanoparticles to acquire durable photo and magneto activities on polymers for different applications.

Deposition of iron oxide nanoparticles on mesoporous alumina network by wet-combustion technology

Abstract The physico-chemical functionality within mesoporous networks dictates their performance as magnets, catalysts, and electro-thermal conductive materials. In this work, a method of wet-combustion was developed for functionalization of a mesoporous network of alumina nanofibres by iron oxide nanoparticles. As the basic fuels, urea and glycine were used. Iron nitrate was applied as an oxidant and a precursor of iron. The fuel type and oxidizer-to-fuel ratio dominantly affects the formation of the final product. The yielded wet-combusted product varies from iron (II) oxides [FeAl2O4] with crystallite size of 12 nm when glycine is used to iron (III) oxides [AlFeO3] with crystallite size of 21 nm when urea is used as a fuel. The agglomerates of spherical nanoparticles of γ-Fe2O3 with an average crystallite size less than 15 nm were homogenously distributed throughout the mesoporous alumina network in both cases. The magnetization curves reveal saturation point is around 6.3 emu.g−1 alongside the Fe2O3 coated-mesoporous alumina nanofibers, and 6 emu.g−1 for a transversal field.

Spontaneous selective deposition of iron oxide nanoparticles on graphite as model catalysts.

Iron oxide nanomaterials participate in redox processes that give them ideal properties for their use as earth-abundant catalysts. Fabricating nanocatalysts for such applications requires detailed knowledge of the deposition and growth. We report the spontaneous deposition of iron oxide nanoparticles on HOPG in defect areas and on step edges from a metal precursor solution. To study the nucleation and growth of iron oxide nanoparticles, tailored defects were created on the surface of HOPG using various ion sources that serve as the target sites for iron oxide nucleation. After solution deposition and annealing, the iron oxide nanoparticles were found to nucleate and coalesce at 400 °C. AFM revealed that the particles on the sp3 carbon sites enabled the nanoparticles to aggregate into larger particles. The iron oxide nanoparticles were characterized as having an Fe3+ oxidation state and two different oxygen species, Fe–O and Fe–OH/Fe–OOH, as determined by XPS. STEM imaging and EDS mapping confirmed that the majority of the nanoparticles grown were converted to hematite after annealing at 400 °C. A mechanism of spontaneous and selective deposition on the HOPG surface and transformation of the iron oxide nanoparticles is proposed. These results suggest a simple method for growing nanoparticles as a model catalyst.

Melamine/Fe3O4 Nanoparticles Based Molecular Imprinted Highly Sensitive Sensor for Determination of Hydrochlorothiazide: An Antihypertensive Drug

A simple, facile and sensitive method for the fabrication of molecularly imprinted sensor is proposed for the determination of hydrochlorothiazide (HCTZ). The sensor is fabricated by the deposition of iron oxide nanoparticles followed by the electropolymerization of melamine monomer in the presence HCTZ at the surface of edge plane pyrolytic graphite. The surface of the imprinted sensor was characterized by using Field Emission Scanning Electron Microscopy, Energy dispersive X-ray analysis, Electrochemical Impedance Spectroscopy, X-ray diffraction, Cyclic Voltammetry and Square Wave Voltammetry. The oxidation of HCTZ occurred in a single, well-defined peak and the peak current was dependent on the concentration of HCTZ in the range 25 × 10−9–10 × 10−6 M. The sensitivity and limit of detection (3σ/b) were found to be 2.342 μM/μA and 4 nM respectively. The proposed method was applied for the determination of HCTZ in the presence of common metabolites present in human system. The obtained results indicated that uric acid, ascorbic acid, hypoxanthine and xanthine did not interfere up to 100 fold concentration. The imprinted sensor was successfully applied for determination of HCTZ in real samples such as pharmaceuticals and urine samples.

Microstructural, electronic and magnetic characterization of Fe-based nanoparticles embedded in Al matrix

Nominal granular iron oxide-aluminum thin films have been prepared by simultaneous deposition of iron oxide nanoparticles, grown by the gas-phase aggregation technique, and an aluminium matrix, grown by conventional magnetron sputtering. Composition, structure and magnetic behavior have been analyzed by different techniques including TEM and AFM microscopies, EDX, RBS, X-ray absorption and Mössbauer spectroscopies and SQUID magnetometry. Both, structure and magnetic behavior, are found to be highly dependent on the preparation conditions. In particular, our work shows that for low matrix/nanoparticle ratios the aluminum is able to partially displace the iron oxide and form a core–shell iron metal-iron oxide structure. For higher ratios, on the other hand, the oxygen atoms become very diluted and their role negligible. In this case a core–shell structure consisting of an iron metal core and an iron–aluminum alloy shell is formed. Magnetization measurements indicate that in the first case the core and the shell are magnetically coupled while in the second case the two phases are magnetically uncoupled, the Fe–Al alloy presenting strong coercivity.

Deposition of Iron Oxide Nanoparticles onto an Oxidic Support Using a Novel Gas-Expanded Liquid Process to Produce Functional Fischer–Tropsch Synthesis Catalysts

Gas expanded liquids (GXL) are solvent systems which enable the controlled deposition of presynthesized iron oxide nanoparticles, based on their size, onto a surface through the use of compressible gas such as CO2. By controlling the applied CO2 pressure, and hence the solvent strength, one can systematically deposit/precipitate nanoparticles of desired sizes. In this study, a technique using a GXL has been developed to controllably deposit iron oxide nanoparticles onto oxidic materials such as alumina and silica. The nanomaterials generated using this technique were then tested for their effectiveness as catalysts in Fischer–Tropsch (FT) synthesis in a fixed bed reactor system under standard low temperature FT conditions. The catalytic performance of these nanoscale iron FT catalysts was compared to control catalysts that were prepared by traditional incipient wetness methods using the same iron loading. Characterization of these GXL-synthesized materials demonstrated that the iron oxide nanoparticles we...

Chemical and magnetic functionalization of graphene oxide as a route to enhance its biocompatibility.

The novel approach for deposition of iron oxide nanoparticles with narrow size distribution supported on different sized graphene oxide was reported. Two different samples with different size distributions of graphene oxide (0.5 to 7 μm and 1 to 3 μm) were selectively prepared, and the influence of the flake size distribution on the mitochondrial activity of L929 with WST1 assay in vitro study was also evaluated. Little reduction of mitochondrial activity of the GO-Fe3O4 samples with broader size distribution (0.5 to 7 μm) was observed. The pristine GO samples (0.5 to 7 μm) in the highest concentrations reduced the mitochondrial activity significantly. For GO-Fe3O4 samples with narrower size distribution, the best biocompatibility was noticed at concentration 12.5 μg/mL. The highest reduction of cell viability was noted at a dose 100 μg/mL for GO (1 to 3 μm). It is worth noting that the chemical functionalization of GO and Fe3O4 is a way to enhance the biocompatibility and makes the system independent of the size distribution of graphene oxide.

Synthesis and in vacuo deposition of iron oxide nanoparticles by microplasma-assisted decomposition of ferrocene

Microplasma-assisted gas-phase nucleation has emerged as an important new approach to produce high-purity, nanometer-sized, and narrowly dispersed particles. This study aims to integrate this technique with vacuum conditions to enable synthesis and deposition in an ultrahigh vacuum compatible environment. The ultimate goal is to combine nanoparticle synthesis with photoemission spectroscopy-based electronic structure analysis. Such measurements require in vacuo deposition to prevent surface contamination from sample transfer, which can be deleterious for nanoscale materials. A homebuilt microplasma reactor was integrated into an existing atomic layer deposition system attached to a surface science multi-chamber system equipped with photoemission spectroscopy. As proof-of-concept, we studied the decomposition of ferrocene vapor in the microplasma to synthesize iron oxide nanoparticles. The injection parameters were optimized to achieve complete precursor decomposition under vacuum conditions, and nanoparticles were successfully deposited. The stoichiometry of the deposited samples was characterized in situ using X-ray photoelectron spectroscopy indicating that iron oxide was formed. Additional transmission electron spectroscopy characterization allowed the determination of the size, shape, and crystal lattice of the particles, confirming their structural properties.

Microwave-assisted catalysis by iron oxide nanoparticles on MCM-41: Effect of the support morphology

Catalytically active heterogeneous catalysts have been prepared via microwave deposition of iron oxide nanoparticles (0.5–1.2wt%) on MCM-41 type silica materials with different morphologies (particles, helical and spheres). This methodology leads to iron oxide nanoparticles composed by a mixture of FeO and Fe2O3 species, being the Fe(II)/Fe(III) peak ratio near to 1.11 by XPS. DRUV spectroscopy indicates the presence of tetrahedral coordinated Fe3+ in the silica framework of the three catalysts as well as some extraframework iron species in the catalysts with particle and sphere-like morphologies. The loading of the nanoparticles does neither affect the mesopore arrangement nor the textural properties of the silica supports, as indicated by SAXS and nitrogen adsorption/desorption isotherms. A detailed investigation of the morphology of the supports in various microwave-assisted catalyzed processes shows that helical mesostructures provide optimum catalytic activities and improved reusabilities in the microwave-assisted redox (selective oxidation of benzyl alcohol) catalyzed process probably due to a combination of lower particle size and higher acidity in comparison with the supports with particle and sphere morphology.

Current Measurements as a Direct Diagnostic for Sub-Monolayer Growth of Nanoparticle Films in Non-Polar Electrophoretic Deposition

Electrophoretic current densities and nanoparticle densities were measured during and after the electrophoretic deposition of iron oxide nanoparticles and were compared to infer the relationship between the quantity of deposited nanoparticles and the measured current. This information led to an assessment of the primary contributors to the measured current during non-polar solvent-based electrophoretic deposition. Such information was employed to monitor and to control sub-monolayer growth of nanoparticle films. Subsequently, the average charge magnitude of each suspended colloidal nanoparticle was calculated to be ±3.2 ± 0.3 electron charges.

MRI Measurement of Regional Lung Deposition in Mice Exposed Nose-Only to Nebulized Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles show potential in magnetic targeting of inhaled aerosols to localized sites within the lung. These particles are also used as contrast agents in magnetic resonance imaging (MRI). In the present work, we examine the feasibility of measuring regional lung deposition of iron oxide nanoparticles using MRI. Mice were exposed nose-only to nebulized superparamagnetic iron oxide nanoparticles. The droplet size distribution in the inhalation chamber was measured using a time-of-flight device. Regional concentrations of iron in the left and right lung were assessed with MRI by measuring the longitudinal relaxation times (T(1)) of the lung tissue in exposed mice, compared to a baseline group. Regional concentrations of iron in the lungs of the mice ranged from 1.1 +/- 0.8 microg/cm(3) (mean +/- one standard deviation, n = 6) in peripheral lung regions to 2.7 +/- 1.4 microg/cm(3) in the central lung, with no significant difference between the left and right lung. The nebulized droplets in the inhalation chamber had mass median aerodynamic diameter (MMAD) of 5.6 +/- 0.8 microm, with a geometric standard deviation (GSD) of 1.30 +/- 0.03 (both values expressed as mean +/- one standard deviation, n = 6). MRI shows promise for in vivo measurement of regional lung concentrations of superparamagnetic iron oxide nanoparticles, and may be useful in studies of lung deposition and clearance.

Novel Magnetically Separable Mesoporous Fe2O3@SBA-15 Nanocomposite with Fully Open Mesochannels for Protein Immobilization

Magnetically separable Fe2O3@SBA-15 nanocomposite with fully open mesochannels and bifunctional surface properties was prepared by selective deposition of iron oxide nanoparticles in the micropores of mesoporous SBA-15 silica with hydrophobic mesopore surface. The iron oxide nanoparticles embedded in the micropores were estimated to be composed of 67% α-Fe2O3 and 33% γ-Fe2O3, and the nanocomposite was found to exhibit superparamagnetic properties. With the bifunctional surface properties, the Fe2O3@SBA-15 nanocomposite showed enhanced adsorption capacity for cytochrome c and a maximum saturated uptake at neutral solution pH.