2O3 Nanocomposite Research Articles

Synthesis and photocatalytic activity of porous ZnO stabilized by TiO2 and Fe3O4 nanoparticles: investigation of pesticide degradation reaction in water treatment.

The present research studies the photocatalytic degradation of a pesticide using TiO2 and Fe3O4 nanoparticles supported on ZnO mesoporous (mZnO) substrate. Chlorpyrifos is an organophosphate pesticide with a C9H11Cl3NO3PS chemical formula. It is broadly utilized in agricultural fields to control product pests. The chlorpyrifos toxicity is acute and still dangerous to any aquatic organisms. The mZnO/TiO2-Fe3O4 material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and N2 adsorption and desorption (Brunauer-Emmett-Teller; BET). In order to optimize three important operating parameters, i.e., chlorpyrifos concentration, mZnO/TiO2-Fe3O4 nanocomposite amount, and pH, for photocatalytic degradation of chlorpyrifos, response surface methodology (RSM) was applied. The central composite design (CCD) including 20 experiments was used to conduct experiments. The highest photodegradation performance of about 94.8% was obtained for a chlorpyrifos concentration of 8ppm, a pH of 10, and an amount of mZnO/TiO2-Fe3O4 nanocomposite of 60mg. The degradation of chlorpyrifos using mZnO/TiO2-Fe3O4 presented good performance (more than 94%). The photocatalytic reaction followed pseudo-first-order kinetics with a rate constant of 0.058min-1 for chlorpyrifos degradation. The results propose that mZnO/TiO2-Fe3O4 nanocomposite is a suitable alternative for the degradation of chlorpyrifos in aqueous solution. The improved photocatalytic efficiency could be attributed to the effective separation of electron-hole pairs via a Z-scheme mechanism.

Effect of Hematite on the Energy Storage Performance of Polyaniline/Zeolite HY/α-Fe2O3 Nanocomposite Supercapacitor Electrode

The main goal of the present work is the elaboration of new nanocomposite conducting poly(aniline) with α-Fe2O3 nanoparticles in the presence of zeolite HY acid in aqueous electrolyte by chemical oxidative polymerization. Various formulations of the polymer were synthesized (5, 10, and 20% of α-Fe2O3) and the nanocomposites poly(aniline)/HY/α-Fe2O3 have been characterized by X-ray diffraction (XRD), SEM analysis, and FT-IR spectroscopy. The electrical conductivity and the UV–visible spectroscopy of the nanocomposites were also investigated. In addition, the electrochemical properties were studied by cyclic voltammetry. (CV) and electrochemical impedance spectroscopy. The optimal ratio between α-Fe2O3 and poly(aniline)/HY was found to be 5 wt%. The specific capacitances of poly(aniline)/HY and nanocomposite were found to be be 630, and 1000 F g−1 respectively at a scan rate of 5 mV/s. Besides, the material possesses a high energy density of 88.88 Wh kg−1 and a maximum power density of 1632.3 W kg−1. These electrochemical results indicate that the PANI/HY/α-Fe2O3 nanocomposites is an attractive candidate for the application in the high-performance energy storage systems.

Spectroscopic Study of Ultra High Molecular Weight Polyethylene (UHMWPE) and Mg-Ni-doped ZnFe<SUB>2</SUB>O<SUB>3</SUB> Nano Composites

The present study aims at investigating the effect of incorporating nano scale MgxNixZn1-xFe2O3 (where x=0.15) as nano fillers on the physical and chemical stability of ultra high molecular weight polyethylene (UHMWPE). The effect of adding 1% and 2% (by weight) nano fillers on the physicochemical properties of UHMWPE/MgxNixZn1-xFe2O3 nano composites have also been investigated by using FTIR, Raman, and UV-VIS spectroscopy. FTIR data of UHMWPE/MgxNixZn1-xFe2O3 nano composites reveal that the addition of MgxNixZn1-xFe2O3 up to 1% induces significant chemical and physical structural alterations in UHMWPE matrix. However, this behavior is found to reduce on increasing the concentration of nano fillers from 1% to 2%. Raman spectroscopic data shows that crystalline contents of UHMWPE remain unaffected with the addition of nano fillers, however; a significant increase in amorphous contents and decrease in all-trans interphase region is observed. This behavior is attributed to the chain scission reactions due to addition of MgxNixZn1-xFe2O3 followed by compression moulding process at high pressure and elevated temperature. Absorption spectroscopy analysis revealed that the incorporation of MgxNixZn1-xFe2O3 results in decrease of energy band gaps from 2.14 eV to 2.08 eV (for direct transition) and from 1.54 eV to 1.38eV (for indirect transition) due to band gap energy which is induced because of MgxNixZn1-xFe2O3 incorporation as nano fillers within the PE matrix.

Strong interfacial charge transfer between hausmannite manganese oxide and alumina for efficient photocatalysis

Well crystalline manganese oxide (Mn3O4) nanoparticles anchored on gamma alumina (γ-Al2O3) have been successfully tailored via a proficient and cost effective chemical process as an efficient material for photo catalysis. XRD indicated the composite formation of γ-Al2O3 and hausmannite structure of Mn3O4. SEM and TEM revealed that hetero structure of Mn3O4/γ-Al2O3 exhibits an amalgam of aggregated nanoparticles and nanorods. XPS demonstrated the chemical states of binary nanocomposite. The band gap tuning has been performed with γ-Al2O3 nanoparticles by assimilating hausmannite Mn3O4 particles into flower like microstructure of Al2O3. The photoluminescence spectra affirmed the enhancement in charge separation in Mn3O4/γ-Al2O3 binary hybrid photocatalyst. The band gap becomes narrow with the increase in concentrations of Mn3O4. The narrowing of band gap is concorded with crystalline domains of primary aggregated particles. To elucidate the mechanism of the photocatalytic activity linear sweep voltammetry was performed. The results showed that Mn3O4/γ-Al2O3 nanocomposite revealed the enhancement in current density as compared to pure γ-Al2O3 which confirmed the electron transfer from Mn3O4 to γ-Al2O3 through the interfacial potential gradient in conduction bands. The optimum concentration of 6.0% Mn3O4/γ-Al2O3 for hybrid structure showed an excellent photocatalytic activity under visible light due to narrow band gap energy. High degree distribution of Mn3O4 nano architects overlying on γ-Al2O3 induces a significant synergic effect between γ-Al2O3 and hausmannite phase of manganese oxide (Mn3O4). This strong interfacial contact between γ-Al2O3 and Mn3O4 endures the quick transfer of photo generated charge carriers across interface.

The Composition and Magnetic Structure of Fe3O4/γ-Fe2O3 Core–Shell Nanocomposites at 300 and 80 K: Mössbauer Study (Part I)

The magnetic structure and the composition of Fe3O4/γ-Fe2O3 nanoparticles are studied at 300 and 80 K with Mossbauer spectroscopy. We found that the Fe3O4/γ-Fe2O3 particles are a core–shell nanocomposite (NC), in which magnetite Fe3O4 is covered with a maghemite shell (γ-Fe2O3). We showed that the thickness of the maghemite shell (γ-Fe2O3) depends on synthesis technology. We found that a layer, whose magnetic structure differs from that of the inner part of the shell (γ-Fe2O3), is formed on the surface of the maghemite shell (γ-Fe2O3) in the Fe3O4/γ-Fe2O3 NC. An intermediate layer is formed in the spin-glass state between the core and the shell. The data on structure of core–shell nanocomposites open up prospects to explain the properties of such particles, which are of great interest to use in various fields, including biomedicine.

Structural and magnetic properties of superconductor NiBi3/α-Bi2O3 synthesized by mechanical alloying

A nanostructured NiBi3/α-Bi2O3 superconductor composite has been synthesized by the process of mechanical alloying through 19 h of high energy ball milling. The kinetics of formation is analyzed in detail by x-ray diffraction and the Rietveld method. A simple method is proposed to determine the crystallinity of the resulting sample by using the background Rietveld fitting that permits a quantitative analysis of the diffuse x-ray profile taking into account the air and Compton scattering. The diffuse scattering is attributed to the formation of a nanocluster of α-Bi2O3 which is confirmed by high-resolution transmission electron microscopy and Raman measurements. The magnetic measurements show superconducting transition at around 4 K and the existence of NiBi3/α-Bi2O3 nanophases with a low irreversibility field at around 1.01 T at 2 K. Analysis of magnetic susceptibility and isothermal magnetic hysteresis of the NiBi3/α-Bi2O3 nanocomposite indicates the simultaneous existence of bulk superconductivity and ferromagnetism below 4 K.

Three-Phase Boundary in Cross-Coupled Micro-Mesoporous Networks Enabling 3D-Printed and Ionogel-Based Quasi-Solid-State Micro-Supercapacitors.

The construction of advanced micro-supercapacitors (MSCs) with both wide working-voltage and high energy density is promising but still challenging. In this work, a series of nitrogen-doped, cross-coupled micro-mesoporous carbon-metal networks (N-STC/Mx Oy ) is developed as robust additives to 3D printing inks for MSCs fabrication. Taking the N-STC/Fe2 O3 nanocomposite as an example, both experimental results and theoretical simulations reveal that the well-developed hierarchical networks with abundantly decorated ultrafine Fe2 O3 nanoparticles not only significantly facilitate the ion adsorption at its three-phase boundaries (Fe2 O3 , N-STC, and electrolyte), but also greatly favor ionic diffusion/transport with shortened pathways. Consequently, the as-prepared N-STC/Fe2 O3 electrode delivers a high gravimetric capacitance (267 F g-1 at 2 mV s-1 ) and outstanding stability in a liquid-electrolyte-based symmetric device, as well as a record-high energy density of 114 Wh kg-1 for an asymmetric supercapacitor. Particularly, the gravimetric capacitance of the ionogel-based quasi-solid-state MSCs by 3D printing reaches 377 F g-1 and the device can operate under a wide temperature range (-10 to 60 °C).

Enhanced microwave absorption characteristic of decorated MWCNTs with La0.9Bi0.1Fe0.8Co0.2O3 multiferroic nanoparticles via coating by PEDOT/Polyaniline co-polymer

The microstructural and microwave absorption characteristics of multiferroic nanocomposite (La0.9Bi0.1Fe0.8Co0.2O3 and MWCNTs) coated with PEDOT/Polyaniline co-polymer, was studied systematically. First, MWCNTs/La0.9Bi0.1Fe0.8Co0.2O3 nanocomposite was synthesized using sol-gel auto-ignition and then PEDOT/Polyaniline polymers were coated on MWCNTs/La0.9Bi0.1Fe0.8Co0.2O3 powder via in-situ polymerization method. The effects of the copolymers coating on the structure, morphology, magnetic and electromagnetic performances of the prepared multiferroic nanocomposite surface were comprehensively investigated via XRD, FESEM, VSM and VNA analysis. Enhanced interfacial dielectric relaxation and also perfectly tuned in impedance matching characteristics were achieved by coating nanocomposite with co-polymers. Coating multiferroic nanocomposite with PEDOT/Polyaniline polymers were leading to decrease in matching thickness. Moreover, the significant improvement in microwave absorption properties were also investigated. It was noticed that the coated nanocomposite achieved maximum reflection loss of −60 dB at 11.8 GHz matching frequency with 3.9 GHz bandwidth.

Synthesis and characterizations of Pd/Mn(Mn1.36Pd0.64)O4 nanocomposite: An experimental and theoretical approach

Due to the growing environmental issues and high energy consumption, there is an emergent need to synthesize the multifunctional materials to reduce energy consumption. Hence, we synthesized the Pd/Mn(Mn1·36Pd0.64)O4 nanocomposite by a simple sol-gel process, and studied their Crystal structure, surface morphology, optical absorbance, electrochemical and magnetic properties. Phase analysis, crystalline structures and crystallite sizes of the nanocomposite were revealed using the X-ray diffraction. Nanosize, globular shape morphologies were revealed using SEM and TEM bright field images. The optical energy band-gap from the optical absorbance spectra was estimated to be 2.22 eV. The electrochemical properties of the composite were observed by cyclic voltammetry studies. The symmetric behavior of the voltammetry plots indicates that the nanocomposite is a favorable candidate used for the fast redox reactions with higher specific capacitance. The vibrating sample magnetometer studies confirm the paramagnetic behavior at room temperature. Electronic structures of the composite reveal the half-metallicity and magnetic behavior of Pd/Mn(Mn1·36Pd0.64)O4 structure.

Significantly enhanced electrostatic energy storage performance of P(VDF-HFP)/BaTiO3-Bi(Li0.5Nb0.5)O3 nanocomposites

Abstract Microelectronics and electrical power systems require dielectric polymer-based dielectrics with high energy density that are simple to process. However, the currently available polymer-based dielectric materials require demanding process conditions and relatively low energy density. Herein, we propose P(VDF-HFP)-based nanocomposite by a simple and practical mechanical method based on a combination of solid phase reaction and sieving to prepare 0.88BaTiO3-0.12Bi(Li0.5Nb0.5)O3 nanoparticles (BT-BLN nps). The experimental and simulation result verify that the BT-BLN nps significantly improve the breakdown strength and energy storage performance of dielectric materials. Remarkably, the highest discharge energy density of the BT-BLN/P(VDF-HFP) nanocomposite film reached 14.2 J/cm3 with the addition of 3 vol% BT-BLN nanofiller at 497 MV/m, which is much higher than that of pure P(VDF- HFP) (Ud ≈ 6.6 J/cm3 and Eb ≈ 391.3 MV/m). Encouragingly, the Young's modulus of BLN-3vol%/P(VDF-HFP) reached 2.6 GPa, which is approximately 2.65 times higher than that of pure P(VDF-HFP) (0.98 GPa). This work established a simple and effective strategy, for solution casting processable dielectrics with performance comparable to that of fillers prepared by the liquid phase method.

Design, synthesis and antiamoebic activity of dysprosium-based nanoparticles using contact lenses as carriers against Acanthamoeba sp.

Contact lenses have direct contact with the corneal surface and can induce sight-threatening infection of the cornea known as Acanthamoeba keratitis. The objective of this study was to evaluate the dysprosium-based nanoparticles (Dy-based NPs), namely Fe3 O4 -PEG-Dy2 O3 nanocomposites and Dy(OH)3 nanorods, as an active component against Acanthamoeba sp., as well as the possibility of their loading onto contact lenses as the drug administering vehicle to treat Acanthamoeba keratitis (AK). The Dy-based NPs were synthesized, and they were loaded onto commercial contact lenses. The loading content of the NPs and their release kinetics was determined based on the absorbance of their colloidal solution before and after soaking the contact lenses. The cytotoxicity of the NPs was evaluated, and the IC50 values of their antiamoebic activity against Acanthamoeba sp. were determined by MTT colorimetric assay, followed by observation on the morphological changes by using light microscopy. The mechanism of action of the Dy-based NPs against Acanthamoeba sp. was evaluated by DNA laddering assays. The loading efficiencies of the Dy-based NPs onto the contact lens were in the range of 30.6-36.1% with respect to their initial concentration (0.5mgml-1 ). The Dy NPs were released with the flux approximately 5.5-11μgcm-2 hr-1 , and the release was completed within 10hr. The emission of the NPs consistently showed a peak at 575nm due to Dy3+ ion, offering the possible monitoring and tracking of the NPs. The SEM images indicated the NPs are aggregated on the surface of the contact lenses. The DNA ladder assay suggested that the cells underwent DNA fragmentation, and the cell death was due most probably to necrosis, rather than apoptosis. The cytotoxicity assay of Acanthamoeba sp. suggested that Fe3 O4 -PEG, Fe3 O4 -PEG-Dy2 O3 , Dy(NO3 )3 .6H2 O and Dy(OH)3 NPs have an antiamoebic activity with the IC50 value being 4.5, 5.0, 9.5 and 22.5μgml-1 , respectively. Overall findings in this study suggested that the Dy-based NPs can be considered as active antiamoebic agents and possess the potential as drugs against Acanthamoeba sp. The NPs could be loaded onto the contact lenses; thus, they can be potentially utilized to treat Acanthamoeba keratitis (AK).

Effects of different graphene-based nanomaterials as elicitors on growth and ganoderic acid production by Ganoderma lucidum.

Graphene-based nanomaterials (GBNs) have attracted considerable interest nowadays due to their wide range of applications. However, very little attention has been paid to the application of nanomaterials as potential elicitors for production of valuable metabolites. Herein, aiming to earn insight into effects of nanomaterials on secondary metabolite biosynthesis by medicinal fungi, we evaluated the influence of GBNs on growth and production of ganoderic acid (GA) by Ganoderma lucidum in submerged culture. Graphene oxide (GO), reduced graphene oxide (rGO), and rGO/Fe3 O4 nanocomposite were synthesized successfully and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy analysis. The prepared nanomaterials were added to the culture of G. lucidum at final concentrations of 50, 100, and 150 mg/L on Day 5. The results showed that the elicitation of G. lucidum with GO and rGO decreased the cell dry weight and GA production slightly, especially in higher concentrations. However, rGO/Fe3 O4 nanocomposite not negatively affected cell growth and improved GA production. G. lucidum growth rate responded to elicitation experiments differently and depended on the type of nanomaterials and their concentrations, but almost all GBNs caused an increase in GA content (mg/100 mg dry weight). Also, field emission scanning electron microscopy morphological study showed that under elicitation, mycelia were more condensed and tightly stacked together. The findings from this study may suggest that GBNs in low concentrations could be applied as elicitors to secondary metabolites production from higher fungus, but further environmental, physiological, and biological studies required.

Structural, morphological and optical properties of multifunctional magnetic-luminescent ZnO@Fe3O4 nanocomposite

In the present work, non-toxic luminescent ZnO nanoparticles (NPs) and magnetic Fe3O4 NPs were separately prepared by co-precipitation method. In order to get the [email protected]3O4 nanocomposite (NCs), both these NPs were embedded in silica matrix. Powder XRD reveals that the formation hexagonal wurzite structure of ZnO and cubic inverse spinel structure of Fe3O4. Both phases were combined in the prepared [email protected]3O4 NCs. FT-IR spectra showed the absorption peaks confirmed the presence of metal-oxygen stretching bands in ZnO NPs, Fe3O4 NPs and [email protected]3O4 NCs samples. VSM results showed both magnetite and [email protected]3O4 have superparamagnetic, whereas the saturation value for [email protected]3O4 NCs was tremendously decreased. Photoluminescence (PL) spectra of ZnO and [email protected]3O4 illustrated that both samples have very good luminescence property. PL intensity of [email protected]3O4 NCs has been reduced as compared to the intensity of bare ZnO NPs. However, [email protected]3O4 still hold very good luminescence property. The as-prepared [email protected]3O4 NCs were successfully demonstrated for magnetic resonance imaging contrast agent application. Hence, it can be simultaneously used for MRI contrast agent as well as optical imaging applications.

Design of chitosan nanocomposite hydrogel for sensitive detection and removal of organic pollutants

In this project, cerium oxide-cobalt oxide (CeO2-Co2O3) nanocomposite-based material have been simply synthesized and intercalated to chitosan (CH) hydrogel to prepare CH/CeO2-Co2O3 nanocomposite hydrogel. CH/CeO2-Co2O3 nanocomposite was applied to nitrophenols reduction where it displayed perfect catalytic activity for 4-nitrophenol as compared to 2-nitrophenol and 2,6-dinitrophenol. Various factors were tested for optimization of catalytic removal approach. Farther, CH/CeO2-Co2O3 nanocomposite catalyst was coated on cotton cloth (CC) as support, which provided high catalytic performance even after reusing three times. CeO2-Co2O3 nanocomposites was also employed as electrochemical sensor where CeO2-Co2O3 was coated on pencil-graphite lead electrode (PGLE) and glassy carbon electrode (GCE) and used as working electrodes to detect different nitrophenols electrochemically via cyclic voltammetry. CeO2-Co2O3 was more selective toward 4-nitrophenol and the reduction peak of 4-nitrophenol was much more enhanced with increase in concentration ranging from 11.80 to 48.75 μM. The detection limit was found to be 0.46 μM (S/N = 5). Thus, the prepared materials were selective for detection and removal of 4-nitrophenol. Various factors were tested to optimize best conditions for developed nanocomposite materials in electrochemical sensing and catalytic removal approaches. Thus, it is expected that the designed nanocomposite will be able to employ as promising material for providing clean water.

Remarkable phosphate removal and recovery from wastewater by magnetically recyclable La2O2CO3/γ-Fe2O3 nanocomposites

Owing to the twin problems of eutrophication and global phosphorus (P) scarcity, the removal and recovery of phosphate from water and wastewater have received increasing attention. Herein, magnetically recyclable La2O2CO3/γ-Fe2O3 adsorbents were rationally designed by derivation from La/Fe binary metal organic framework (MOF) precursors via calcination treatment. Based upon preliminary screening of as-prepared La2O2CO3/γ-Fe2O3 nanocomposites with different La-to-Fe molar ratios in terms of phosphate sorption capacity and magnetic property as well as La content, La2O2CO3/γ-Fe2O3 nanocomposite with a La-to-Fe molar ratio of 2:1 was selected for further characterization and adsorption performance evaluation. Batch adsorption experiments showed that La2O2CO3/γ-Fe2O3 (2:1) adsorbent exhibited a remarkable phosphate sorption capacity of 134.82 mg P/g, a fast sorption kinetic, strong selectivity for phosphate in the presence of co-existing anions, and a wide applicable pH range of 3−9. Furthermore, La2O2CO3/γ-Fe2O3 (2:1) sorbent displayed an excellent sorption performance for low-concentration wastewater, a low dosage of 0.1 g/L was sufficiently enough for reducing P-concentration from 0.5 mg P/L to below 10 μg P/L within 20 min. In a real sewage of 2.68 mg P/L, 0.2 g/L of sorbent could reduce the concentration of phosphate to <0.01 mg P/L within 50 min. Moreover, over 83.1 % of original sorption capacity could be retained after 5 consecutive regeneration cycles, showing great regenerative performance of the adsorbent. These development is expected to be meaningful for practical water purification.

Hybrid nanomaterial of ZnFe2O4/α-Fe2O3 implanted graphene for electrochemical glucose sensing application

Nonenzymatic electrochemical glucose sensing of ZnFe2O4/α-Fe2O3 implanted graphene (ZFGr) was investigated by exploiting the electrocatalytic property of ZnFe2O4/α-Fe2O3 nanocomposite and electrical conductivity of graphene. The ZnFe2O4/α-Fe2O3 nanocomposite was implanted on graphene sheets with a process involving combustion and characterized using XRD, FTIR, Raman, XPS, FESEM, and TEM analyses. The electron microscopic images demonstrated the implantation of ZnFe2O4/α-Fe2O3 nanocomposite on graphene and the effects of implantation on the optical, magnetic and electrochemical properties of ZnFe2O4/α-Fe2O3 nanocomposite were discussed. The electrocatalytic efficiency of ZFGr hybrid nanomaterial towards glucose was investigated by employing EIS, CV, and chronoamperometry techniques. The electrochemical analysis revealed the application prospects of this hybrid nanomagnetic materials in electrochemistry due to its significant amperometric response for the electrochemical detection of glucose with a sensitivity of 609 μA(mM)−1 cm−2.

Metal-organic frameworks-derived porous α-Fe2O3 spindles decorated with Au nanoparticles for enhanced triethylamine gas-sensing performance

Recently, metal organic frameworks (MOFs) materials with varied shapes and tunable pore sizes have been regarded as ideal templates for preparing porous metal oxides. In this work, porous α-Fe2O3 spindles were prepared by using Fe-MIL-88 as the precursor and successfully combined with Au nanoparticles (Au NPs). Meanwhile, the components and morphologies of Au/α-Fe2O3 nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). Characterization results revealed that Au nanoparticles were homogeneously attached on the surface of porous α-Fe2O3 spindles. Gas-sensing tests exhibit that Au/α-Fe2O3 nanocomposites show higher response, excellent selectivity and fast response and recovery towards triethylamine (TEA). This work confirms the advantages of Au catalyst-loaded and MOF-derived porous nanostructures in gas detection.

Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites.

This paper describes the effects of α-Al2O3 nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al2O3 nanocomposites. The α-Al2O3 nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al2O3 nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al2O3 nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 × 10−13 S/m to 1.04 × 10−13 S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al2O3 nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al2O3 nanocomposites.

Mesoporous Ca2Fe2O5/α-Fe2O3 nanocomposite anode for lithium-ion batteries

In this work, a hybrid strategy for preparing a mesoporous Ca2Fe2O5/α-Fe2O3 nanocomposite has been demonstrated to exhibit great electrochemical performance as anode materials for lithium-ion batteries. The mesoporous Ca2Fe2O5/α-Fe2O3 nanocomposite has been synthesized through the mixture of Ca/Fe-hydroxides and deionized water via a facile solvothermal process followed by calcination at 700 ​°C with air atmosphere. The prepared mesoporous Ca2Fe2O5/α-Fe2O3 nanocomposite shows great rate capability, excellent cycling stability, and high specific capacity associated with surface capacitance-controlled capacity. The high performance can be ascribed to the beneficial effects of the unique mesoporous nanocomposite, which buffers the volume change during electrode reactions, increases the contact area of the electrode/electrolyte, facilitates electrolyte diffuse and favors Li+ transport.

Hydrothermal Synthesis of Activated Carbon/α-Fe2O3 Nanocomposite and Its Application for Removing Tartrazine Dye

Hematite containing activated carbon (AC/α-Fe2O3) nanocomposite has been prepared by hydrothermal method and used as photocatalyst for removing tartrazine dye. Hematite was extracted from iron sand while activated carbon was derived from coffee waste which was activated using hydrochloric acid. The structure and morphology of photocatalyst was characterized by means of X-ray diffraction (XRD), nitrogen adsorption-desorption (BET) and Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). These techniques indicate that the AC/α-Fe2O3 nanocomposite has an average crystallite size of 35.47 nm and specific surface area of 41.52 m2/g. The photocatalytic activity evaluation showed that various factors influencing the removal of tartrazine dye including pH of dye solution, photocatalyst dosage, dye concentration and irradiation time. The results showed that AC/α-Fe2O3 nanocomposite can remove tartrazine up to 91.01% under UV light and 93.69% under solar light which were obtained at pH value of 2, photocatalyst dosage of 250 mg and initial concentration of tartrazine is 15 ppm with irradiation time for 210 min under UV light and 180 min under solar light. The AC/α-Fe2O3 nanocomposite also can remove tartrazine dye contained in noodle waste water up to 94.67% and 97.86 under UV light irradiation for 150 min and 120 min under solar light irradiation, respectively.