Preparation and drug-loading properties of Fe3O4/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

International Nuclear Information System (INIS)

Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

2013-01-01

Fe 3 O 4 /poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe 3 O 4 nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50–120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe 3 O 4 nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release

Magnetic ordered mesoporous Fe3O4/CeO2 composites with synergy of adsorption and Fenton catalysis

Science.gov (United States)

Li, Keyan; Zhao, Yongqin; Song, Chunshan; Guo, Xinwen

2017-12-01

Magnetic Fe3O4/CeO2 composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO2 as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N2 adsorption/desorption analysis. The mesoporous Fe3O4/CeO2 composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe3O4/CeO2 was much higher than that of irregular porous Fe3O4/CeO2. The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO2, high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce3+ content and the synergistic effect between Fe and Ce. The mesoporous Fe3O4/CeO2 composite presented low metal leaching (iron 0.22 mg L-1 and cerium 0.63 mg L-1), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.

Facile preparation of magnetic mesoporous Fe_3O_4/C/Cu composites as high performance Fenton-like catalysts

International Nuclear Information System (INIS)

Li, Keyan; Zhao, Yongqin; Janik, Michael J.; Song, Chunshan; Guo, Xinwen

2017-01-01

Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe_3O_4/C/Cu was obtained by calcining tartrate under N_2. • Fe_3O_4/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe_2O_3/CuO and α-Fe_2O_3/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe_3O_4/C/Cu was obtained by calcining the tartrate precursor under N_2 atmosphere at 500 °C. The Fe_3O_4/C/Cu composite possessed mesoporous structure and large surface area up to 133 m"2 g"−"1. The Fenton catalytic performance of Fe_3O_4/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe"3"+ to Fe"2"+, which accelerated the Fe"3"+/Fe"2"+ cycles and favored H_2O_2 decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe"3"+ and Cu"2"+, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe_3O_4/C/Cu-H_2O_2 system, and MB (100 mg L"−"1) was nearly removed within 60 min. The Fe_3O_4/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile, cheap and green method for the synthesis of mesoporous composites as excellent Fenton-like catalysts, without any additional reductants or organic

Fabrication, structure, and properties of Fe{sub 3}O{sub 4}-C encapsulated with YVO{sub 4}:Eu{sup 3+} composites

Energy Technology Data Exchange (ETDEWEB)

Shi Jianhui; Tong Lizhu; Liu Deming; Yang Hua, E-mail: huayang86@sina.com [Jilin University, College of Chemistry (China)

2012-03-15

The use of carbon shells offers many advantages in surface coating or surface modification due to their surface with activated carboxyl and carbonyl groups. In this study, the Fe{sub 3}O{sub 4}-C-YVO{sub 4}:Eu{sup 3+} composites were prepared through a simple sol-gel process. Reactive carbon interlayer was introduced as a key component, which separates lanthanide-based luminescent component from the magnetite, more importantly, it effectively prevent oxidation of the Fe{sub 3}O{sub 4} core during the whole preparation process. The morphology, structure, magnetic, and luminescent properties of the composites were characterized by transmission electron microscopy (TEM), high-resolution TEM, X-ray diffraction, X-ray photoelectron spectra, VSM, and photoluminescent spectrophotometer. As a result, the Fe{sub 3}O{sub 4}-C/YVO{sub 4}:Eu{sup 3+} composites with well-crystallized and core-shell structure were prepared and the YVO{sub 4}:Eu{sup 3+} luminescent layer decorating the Fe{sub 3}O{sub 4}-C core-shell microspheres are about 10 nm. In addition, the Fe{sub 3}O{sub 4}-C-YVO{sub 4}:Eu{sup 3+} composites have the excellent magnetic and luminescent properties, which allow them great potential for bioapplications such as magnetic bioseparation, magnetic resonance imaging, and drug/gene delivery.

Controllable synthesis and characterization of Fe3O4/Au composite nanoparticles

International Nuclear Information System (INIS)

Xing, Yan; Jin, Yan-Yan; Si, Jian-Chao; Peng, Ming-Li; Wang, Xiao-Fang; Chen, Chao; Cui, Ya-Li

2015-01-01

Fe 3 O 4 /Au composite nanoparticles (GoldMag NPs) have received considerable attention because of their advantageous properties arisen from both individual Au and Fe 3 O 4 nanoparticles. Many efforts have been devoted to the synthesis of these composite nanoparticles. Herein, GoldMag NPs were reported to be synthesized by two-step method. Fe 3 O 4 nanoparticles were prepared by co-precipitation and modified by the citric acid, and then citric acid-coated Fe 3 O 4 nanoparticles were used as seeds in sodium citrate solution to reduce the HAuCl 4 . The size of obtained nanoparticles was geared from 25 to 300 nm by controlling the concentration of reactants. The GoldMag NPs were characterized by UV–vis spectrometer, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The GoldMag NPs showed good superparamagnetism at room temperature and were well dispersed in water with surface plasmon resonance absorption peak varied from 538 nm to 570 nm. - Highlights: • A low cost, simple manipulation and nontoxic approach was designed for preparation of magnetic Fe 3 O 4 /Au (GoldMag NPs) nanocomposites. • The size of GoldMag NPs could be controlled from 25 to 300 nm by varying the concentration of reactants. • GoldMag NPs possessed good magnetic response, high dispersion, and good stability

Preparation and photoelectric properties of p-CaFe2O4/n-WO3 composites

International Nuclear Information System (INIS)

Wan, Ruiqin; Jia, Caihong; Zhang, Weifeng

2012-01-01

Highlights: ► Surface photovoltage spectroscopy investigation on p-CaFe 2 O 4 /n-WO 3 composites. ► The photovoltaic response is enhanced in p-CaFe 2 O 4 /n-WO 3 composites. ► The multielectron process and high rate of carrier migration in WO 3 . - Abstract: Composites of p-CaFe 2 O 4 /n-WO 3 are prepared via a sol–gel technique. Their structures and optical properties are characterized with X-ray diffraction, scanning electron microscopy and UV–vis absorption spectroscopy. The photoelectric characteristics are investigated by surface photovoltage spectroscopy combined with electric field induced surface photovoltage spectroscopy. The results indicate that CaFe 2 O 4 can well form a p–n type composite with WO 3 , and the intensity and spectral region of surface photovoltaic response for the composites are strongly dependent on the molar ratio of two components. The enhancement in photoelectric properties and the effective separation of photogenerated carriers could be attributed to the energy level matching between the two components, multielectron process and the high migration rate in WO 3 .

Hydrothermal synthesis of magnetic Fe{sub 3}O{sub 4}/graphene composites with good electromagnetic microwave absorbing performances

Energy Technology Data Exchange (ETDEWEB)

Zhu, Lingyu; Zeng, Xiaojun; Li, Xiaopan; Yang, B., E-mail: byang@buaa.edu.cn; Yu, Ronghai, E-mail: rhyu@buaa.edu.cn

2017-03-15

The Fe{sub 3}O{sub 4} sub-microspheres have been embedded uniformly into the reduced graphene oxide (rGO) to form a new-type Fe{sub 3}O{sub 4}/rGO composites through a one-pot solvothermal method. The dielectric properties for these magnetic Fe{sub 3}O{sub 4}/rGO composites can be greatly tuned by their different rGO additions. A good impedance matching from the balanced dielectric and magnetic loss is achieved in the Fe{sub 3}O{sub 4}/rGO composites with 4 wt% rGO addition, which dominates their excellent microwave absorbing performances including the minimum reflection loss (RL) value of −45 dB at a frequency of 8.96 GHz with a sample thickness of 3.5 mm and an effective absorption bandwidth of 3.2 GHz (below −10 dB) superior to those of the most magnetic materials and carbon-based composites. The controlled Fe{sub 3}O{sub 4}/rGO composite structure also exhibits high chemical stability and low density, which shows great potential application in high-performance electromagnetic microwave-absorbing materials. - Highlights: • Magnetic Fe{sub 3}O{sub 4}/rGO composites are fabricated by a facile solvothermal method. • The dielectric properties for the Fe{sub 3}O{sub 4}/rGO composites can be tuned. • The Fe{sub 3}O{sub 4}/rGO composites exhibits high chemical stability and low density. • Excellent microwave absorption performances for the composites are obtained.

Preparation and characterization of Fe3O4@Au-C225 composite targeted nanoparticles for MRI of human glioma.

Science.gov (United States)

Ge, Yaoqi; Zhong, Yuejiao; Ji, Guozhong; Lu, Qianling; Dai, Xinyu; Guo, Zhirui; Zhang, Peng; Peng, Gang; Zhang, Kangzhen; Li, Yuntao

2018-01-01

To study the characterization of Fe3O4@Au-C225 composite targeted MNPs. Fe3O4@Au-C225 was prepared by the absorption method. The immunosorbent assay was used to evaluate its absorption efficiency at C225 Fc. ZETA SIZER3000 laser particle size analyzer, ultraviolet photometer and its characteristics were analyzed by VSM. the targeting effect of Fe3O4@Au-C225 composite targeted MNPs on U251 cells in vitro were detected by 7.0 Tesla Micro-MR; and subcutaneous transplanted human glioma in nude mice were performed the targeting effect in vivo after tail vein injection of Fe3O4@Au-C225 composite targeted MNPs by MRI. The self-prepared Fe3O4@Au composite MNPs can adsorb C225 with high efficiency of adsorption so that Fe3O4@Au-C225 composite targeted MNPs were prepared successfully. Fe3O4@Au-C225 composite targeted MNPs favorably targeted human glioma cell line U251 in vitro; Fe3O4@Au-C225 composite targeted MNPs have good targeting ability to xenografted glioma on nude mice in vivo, and can be traced by MRI. The Fe3O4@Au-C225 composite targeted MNPs have the potential to be used as a tracer for glioma in vivo.

Magneto electric effects in BaTiO3-CoFe2O4 bulk composites

Science.gov (United States)

Agarwal, Shivani; Caltun, O. F.; Sreenivas, K.

2012-11-01

Influence of a static magnetic field (HDC) on the hysteresis and remanence in the longitudinal and transverse magneto electric voltage coefficients (MEVC) observed in [BaTiO3]1-x-[CoFe2O4]x bulk composites are analyzed. Remanence in MEVC at zero bias (HDC=0) is stronger in the transverse configuration over the longitudinal case. The observed hysteretic behavior in MEVC vs. HDC is correlated with the changes observed in the magnetostriction characteristics (λ and dλ/dH) reported for [BaTiO3]1-x-[CoFe2O4]x bulk composites.

Mechanical and Thermal Properties of Palm-Based Polyurethane Composites Filled with Fe3O4, PANI and PANI/ Fe3O4

International Nuclear Information System (INIS)

Hao, L.C.; Sahrim Ahmad; Khairiah Badri

2011-01-01

In-situ polymerization method was used to prepare palm-based polyurethane (PU) composites loading with 15 wt % magnetite (Fe 3 O 4 ), poly aniline (PANI) and Fe 3 O 4 coated with PANI labeled as PU15, PP and PPM, respectively. FTIR spectroscopy analysis indicated a shift in the carbonyl, C=O and NH in PP. The shift of the peak indicated that there was hydrogen bonding between the C=O (proton acceptor) of urethane with NH (proton-donator) of PANI. PPM gave the highest impact and flexural strengths at 4875 kJ/ m 2 and 42 MPa, respectively but with the lowest flexural modulus (1050 MPa). Two-stage degradation behavior was observed in the TGA thermo gram. (author)

Facile preparation and enhanced microwave absorption properties of flake carbonyl iron/Fe{sub 3}O{sub 4} composite

Energy Technology Data Exchange (ETDEWEB)

Min, Dandan, E-mail: mdd4776@126.com; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

2017-08-01

Highlights: • Flake carbonyl iron/Fe{sub 3}O{sub 4} composites were prepared by surface oxidation technique. • Lower permittivity and modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. • Enhanced absorption efficiency and broader absorption band were obtained. - Abstract: Flake carbonyl iron/Fe{sub 3}O{sub 4} (FCI/Fe{sub 3}O{sub 4}) composites with enhanced microwave absorption properties were prepared by a direct and flexible surface oxidation technique. The phase structures, morphology, magnetic properties, frequency-dependent electromagnetic and microwave absorption properties of the composites were investigated. The measurement results showed that lower permittivity as well as modest permeability was obtained by the FCI/Fe{sub 3}O{sub 4} composites. The calculated microwave absorption properties indicated that enhanced absorption efficiency and broader absorption band were obtained by the FCI/Fe{sub 3}O{sub 4} composite comparing with the FCI composite. The absorption frequency range with reflection loss (RL) below −5 dB of FCI/Fe{sub 3}O{sub 4} composites at reaction time of 90 min at thickness of 1.5 mm is 13.3 GHz from 4.7 to 18 GHz, while the bandwidth of the FCI composite is only 5.9 GHz from 2.6 to 8.5 GHz at the same thickness. Thus, such absorbers could act as effective and wide broadband microwave absorbers in the GHz range.

Molecular [(Fe3)–(Fe3)] and [(Fe4)–(Fe4)] coordination cluster pairs as single or composite arrays.

Science.gov (United States)

Sañudo, E Carolina; Uber, Jorge Salinas; Pons Balagué, Alba; Roubeau, Olivier; Aromí, Guillem

2012-08-06

The synthesis of molecular cluster pairs is a challenge for coordination chemists due to the potential applications of these species in molecular spintronics or quantum computing. The ligand H(4)L, 1,3-bis-(3-oxo-3-(2-hydroxyphenyl)-propionyl)-2-methoxybenzene, has been successfully used to obtain a series of such complexes using the basic Fe(III) trinuclear carboxylates as starting materials. Synthetic control has allowed the isolation of the two molecular cluster pairs that form the composite [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2)[Fe(3)O(PhCO(2))(5)(py)(H(2)L)](2) (1). The dimers of trinuclear units, [Fe(3)O(PhCO(2))(5)(H(2)O)(H(2)L)](2) (2) and [Fe(3)O(o-MePhCO(2))(5)(H(2)L)(py)](2) (3), and the dimers of tetranuclear units, [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2) (4) and [Fe(4)O(2)(o-MePhCO(2))(6)(H(2)L)(pz)](2) (5), are presented here. The magnetic properties of the reported aggregates show that they are pairs of semi-independent clusters weakly interacting magnetically as required for two-qubit quantum gates.

Synthesis and magnetic properties of hard magnetic (CoFe{sub 2}O{sub 4})-soft magnetic (Fe{sub 3}O{sub 4}) nano-composite ceramics by SPS technology

Energy Technology Data Exchange (ETDEWEB)

Fei Chunlong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Zhang Yue [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Yang Zhi; Liu Yong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Xiong Rui, E-mail: wudawujiron@163.co [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China) and Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Shi Jing [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); International Center for Materials Physics, Shen Yang 110015 (China); Ruan Xuefeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China)

2011-07-15

CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were synthesized by Spark Plasma Sintering. The X-ray diffraction patterns show that all samples are composed of CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} phases when the sintering temperature is below 900 {sup o}C. It is found that the magnetic properties strongly depend on the sintering temperature. The two-step hysteresis loops for samples sintered below 500 {sup o}C are observed, but when sintering temperature reaches 500 {sup o}C, the step disappears, which indicates that the CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} are well exchange coupled. As the sintering temperature increases from 500 to 800 {sup o}C, the results of X-ray diffractometer indicate the constriction of crystalline regions due to the ion diffusion at the interfaces of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} phases, which have great impact on the magnetic properties. - Research highlights: In this work, a series of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were prepared through SPS. The magnetic properties of these ceramics have been studied in detail. It is found that the magnetic properties strongly depend on the sintering temperature.

Graphene derivatives/Fe{sub 3}O{sub 4}/polymer nanocomposite films: Optical and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Hatel, Rhizlane [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco); Goumri, Meryem [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco); XLIM UMR 7252- University of Limoges/CNRS, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); Ratier, Bernard [XLIM UMR 7252- University of Limoges/CNRS, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); Baitoul, Mimouna, E-mail: baitoul@yahoo.fr [University Sidi Mohammed Ben Abdellah, Faculty of Sciences Dhar El Mahraz, Laboratory of Solid State Physics, Group of Polymers and Nanomaterials, PO Box 1796, Atlas, Fez 30000 (Morocco)

2017-06-01

This paper reports a simple solution casting method for the preparation of nanocomposite films in which graphene oxide (GO)/Fe{sub 3}O{sub 4} nanocomposites are incorporated into poly (vinyl alcohol) (PVA) matrix. The films obtained with different weight percent of GO/Fe{sub 3}O{sub 4} (0.5, 0.7 and 1 wt%) are subjected an in situ chemical and thermal reduction in order to explore the evolution and interactions between these components under different treatments and get an insight into on how this can affects the optical and electrical properties of these nanocomposites. Characterization was carried out using, UV–Vis absorption, Photoluminescence, electrical conductivity measurements, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Strong covalent functionalization occurs between the polymer and graphene derivatives (GD)/Fe{sub 3}O{sub 4} hybrids. The experimental results obtained for our nanocomposites films exhibit significant enhancement in properties highlighted the efficiency of the in situ thermal reduction. The high absorption with strong photoluminescence and electrical conductivity achieved might promote these nanocomposites for opto-electronic devices in near future. - Highlights: • Novel inorganic-organic hybrid flexible films were successfully prepared. • Good interfacial interaction between the graphene/Fe{sub 3}O{sub 4} and the hydroxyl-rich PVA. • Optical and electrical properties of Graphene Derivatives/Fe{sub 3}O{sub 4}/PVA were investigated. • Thermally reduced GO/Fe{sub 3}O{sub 4}/PVA films show high absorption and strong photoluminescence.

Preparation and characterization of Fe3O4/SiO2/Bi2MoO6 composite as magnetically separable photocatalyst

International Nuclear Information System (INIS)

Hou, Xuemei; Tian, Yanlong; Zhang, Xiang; Dou, Shuliang; Pan, Lei; Wang, Wenjia; Li, Yao; Zhao, Jiupeng

2015-01-01

Highlights: • Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 composite was prepared by a hydrothermal method. • The composite has an enhanced visible absorption compared with pure Bi 2 MoO 6 . • The magnetic photocatalyst displayed excellent stability and reusability. • O 2 ·− and · OH play a major role during the photocatalytic process. - Abstract: In this paper, Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 microspheres were prepared by a facile hydrothermal method. The scanning electron microscope (SEM) results revealed that flower-like three dimensional (3D) Bi 2 MoO 6 microspheres were decorated with Fe 3 O 4 /SiO 2 magnetic nanoparticles. The UV–vis diffuse reflection spectra showed extended absorption within the visible light range compared with pure Bi 2 MoO 6 . We evaluated the photocatalytic activities of Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 microspheres on the degradation of Rhodamine B (RhB) under visible light irradiation and found that the obtained composite exhibited higher photocatalytic activity than pure Bi 2 MoO 6 and P25. Moreover, the Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 composite also displayed excellent stability and their photocatalytic activity decreased slightly after reusing 5 cycles. Meanwhile, the composite could be easily separated by applying an external magnetic field. The trapping experiment results suggest that superoxide radical species O 2 ·− and hydroxyl radicals · OH play a major role in Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 system under visible light irradiation. The combination of flower-like three dimensional (3D) Bi 2 MoO 6 microspheres and Fe 3 O 4 /SiO 2 magnetic nanospheres provides a useful strategy for designing multifunctional nanostructure materials with enhanced photocatalytic activities in the potential applications of water purification

Mössbauer Studies of Core-Shell FeO/Fe3O4 Nanoparticles

Science.gov (United States)

Kamzin, A. S.; Valiullin, A. A.; Khurshid, H.; Nemati, Z.; Srikanth, H.; Phan, M. H.

2018-02-01

FeO/Fe3O4 nanoparticles were synthesized by thermal decomposition. Electron microscopy revealed that these nanoparticles were of the core-shell type and had a spherical shape with an average size of 20 nm. It was found that the obtained FeO/Fe3O4 nanoparticles had exchange coupling. The effect of anisotropy on the efficiency of heating (hyperthermic effect) of FeO/Fe3O4 nanoparticles by an external alternating magnetic field was examined. The specific absorption rate (SAR) of the studied nanoparticles was 135 W/g in the experiment with an external alternating magnetic field with a strength of 600 Oe and a frequency of 310 kHz. These data led to an important insight: the saturation magnetization is not the only factor governing the SAR, and the efficiency of heating of magnetic FeO/Fe3O4 nanoparticles may be increased by enhancing the effective anisotropy. Mössbauer spectroscopy of the phase composition of the synthesized nanoparticles clearly revealed the simultaneous presence of three phases: magnetite Fe3O4, maghemite γ-Fe2O3, and wustite FeO.

Electrospun ZnFe{sub 2}O{sub 4}-based nanofiber composites with enhanced supercapacitive properties

Energy Technology Data Exchange (ETDEWEB)

Agyemang, Frank Ofori; Kim, Hern, E-mail: hernkim@mju.ac.kr

2016-09-15

Highlights: • Electrospun ZnFe{sub 2}O{sub 4}-based nanofibers were successfully fabricated. • The electrochemical properties of ZnFe{sub 2}O{sub 4} were enhanced by addition of ZnO and Fe{sub 2}O{sub 3.} • A specific capacitance of 590 F g{sup −1} was achieved from a CV curve at a scan rate of 5 mV s{sup −1.} • The electrode materials poses excellent cycling stability even after 3000 cycles. - Abstract: Herein, we are reporting a facile method to synthesis ZnFe{sub 2}O{sub 4}-based nanofibers (ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}) via the electrospinning technique using zinc acetonate and ferric acetonate as the metal oxide precursor and polyvinyl pyrrolidone (PVP) as the polymer. The as-prepared electrospun nanofiber composites were calcined at 500 °C to obtain crystalline porous nanofibers. The effect of different compositions on the morphology of each sample as well as their electrochemical properties when employed as electrode materials was studied. The results show that the as-prepared electrodes exhibited excellent performance with their specific capacitances calculated from the CV curves as 590, 490 and 450 F g{sup −1} for Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} respectively at a scan rate of 5 mV s{sup −1}. Excellent stability of the electrodes was also observed even after 3000 cycles. The results obtained suggest these electrode materials might be promising candidates for supercapacitor application.

PENGUJIAN AKTIVITAS KOMPOSIT Fe2O3-SiO2 SEBAGAI FOTOKATALIS PADA FOTODEGRADASI 4-KLOROFENOL (The Activity Test of Fe2O3-SiO2 Composite As Photocatalyst on 4-Chlorophenol Photodegradation

Directory of Open Access Journals (Sweden)

Eko Sri Kunarti

2009-03-01

Full Text Available ABSTRAK  Pada penelitian ini telah dilakukan pengujian aktivitas komposit Fe2O3-SiO2 sebagai fotokatalis pada fotodegradasi 4-klorofenol. Penelitian diawali dengan preparasi dan karakterisasi fotokatalis Fe2O3-SiO2. Preparasi dilakukan dengan metode sol-gel pada temperatur kamar menggunakan tetraetil ortosilikat (TEOS dan besi (III nitrat sebagai prekursor diikuti dengan perlakuan termal pada temperature 500 oC. Karakterisasi dilakukan dengan metode spektrometri inframerah, difraksi sinar-X dan spektrometri fluoresensi sinar-X. Uji aktivitas komposit untuk fotodegradasi 4-klorofenol dilakukan dalam reaktor tertutup yang dilengkapi dengan lampu UV. Pada uji ini telah dipelajari pengaruh waktu penyinaran dan pH larutan terhadap efektivitas fotodegradasi 4-klorofenol. Hasil penelitian menunjukkan bahwa komposit Fe2O3-SiO2 dapat dipreparasi dengan metode sol-gel pada temperatur kamar diikuti perlakuan termal. Komposit Fe2O3-SiO2 dapat meningkatkan efektivitas fotodegradasi 4-klorofenol dari 11,86 % menjadi 55,38 %. Efektivitas fotodegradasi 4- klorofenol dipengaruhi waktu penyinaran dan pH larutan yang semakin lama waktu penyinaran efektifitas fotodegradasi semakin tinggi, namun waktu penyinaran yang lebih lama dari 4 jam dapat menurunkan efektivitasnya. pH larutan memberikan pengaruh yang berbeda-beda pada efektivitas fotodegradasi 4-klorofenol.   ABSTRACT The activity test of Fe2O3-SiO2 composite as photocatalyst on 4-chlorophenol photodegradation has been studied. The research was initiated by preparation of Fe2O3-SiO2 photocatalyst and followed by characterization. The preparation was conducted by sol-gel method at room temperature using tetraethylorthosilicate (TEOS and iron (III nitrate as precursors followed by thermal treatment at a temperature of 500oC. The characterizations were performed by X-ray Diffraction (XRD, Infrared and X-ray Fluorescence Spectrophotometry. The photocatalytic activity test of composites for 4 chlorophenol

Facile synthesis of monodisperse superparamagnetic Fe{sub 3}O{sub 4}/PMMA composite nanospheres with high magnetization

Energy Technology Data Exchange (ETDEWEB)

Lan Fang; Liu Kexia; Jiang Wen; Zeng Xiaobo; Wu Yao; Gu Zhongwei, E-mail: Yaowu_amanda@126.com, E-mail: zwgu@scu.edu.cn [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

2011-06-03

Monodisperse superparamagnetic Fe{sub 3}O{sub 4}/polymethyl methacrylate (PMMA) composite nanospheres with high saturation magnetization were successfully prepared by a facile novel miniemulsion polymerization method. The ferrofluid, MMA monomer and surfactants were co-sonicated and emulsified to form stable miniemulsion for polymerization. The samples were characterized by DLS, TEM, FTIR, XRD, TGA and VSM. The diameter of the Fe{sub 3}O{sub 4}/PMMA composite nanospheres by DLS was close to 90 nm with corresponding polydispersity index (PDI) as small as 0.099, which indicated that the nanospheres have excellent homogeneity in aqueous medium. The TEM results implied that the Fe{sub 3}O{sub 4}/PMMA composite nanospheres had a perfect core-shell structure with about 3 nm thin PMMA shells, and the core was composed of many homogeneous and closely packed Fe{sub 3}O{sub 4} nanoparticles. VSM and TGA showed that the Fe{sub 3}O{sub 4}/PMMA composite nanospheres with at least 65% high magnetite content were superparamagnetic, and the saturation magnetization was as high as around 39 emu g{sup -1} (total mass), which was only decreased by 17% compared with the initial bare Fe{sub 3}O{sub 4} nanoparticles.

Controllable synthesis, magnetic and biocompatible properties of Fe3O4 and α-Fe2O3 nanocrystals

International Nuclear Information System (INIS)

Zhou, Xi; Shi, Yanfeng; Ren, Lei; Bao, Shixiong; Han, Yu; Wu, Shichao; Zhang, Honggang; Zhong, Lubin; Zhang, Qiqing

2012-01-01

Iron oxide nanocrystals (NCs) with a series of well-controlled morphologies (octahedron, rod, wire, cube and plate) and compositions (Fe 3 O 4 and α-Fe 2 O 3 ) were synthesized via a facile hydrothermal process. The morphological and compositional control of various iron oxide NCs was based on the regulations of precursor thermolysis kinetics and surfactants. The obtained samples were characterized by XRD, SEM, TEM, SQUID and cytotoxicity test. These as-prepared iron oxide NCs showed excellent magnetic properties and good biocompatibility, paving the way for their high-efficiency bio-separation and bio-detection applications. - Graphical Abstract: Schematic illustration for the formation of iron oxide NCs (Fe 3 O 4 and α-Fe 2 O 3 ) with different controlled morphologies and compositions. Highlights: ► Iron oxide NCs with a series of well-controlled morphologies (octahedron, rod, wire, cube, and plate) and compositions (Fe 3 O 4 and α-Fe 2 O 3 ) were synthesized via a facile hydrothermal method. ► The mechanism of the morphological and compositional control process is directly related to precursor thermolysis kinetics and surfactants. ► These iron oxide NCs exhibited excellent magnetic response and good biocompatibility, which should have great applications in the cell separation and biodetection.

Rapid removal of uranium from aqueous solutions using magnetic Fe3O4@SiO2 composite particles.

Science.gov (United States)

Fan, Fang-Li; Qin, Zhi; Bai, Jing; Rong, Wei-Dong; Fan, Fu-You; Tian, Wei; Wu, Xiao-Lei; Wang, Yang; Zhao, Liang

2012-04-01

Rapid removal of U(VI) from aqueous solutions was investigated using magnetic Fe(3)O(4)@SiO(2) composite particles as the novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time and initial U(VI) concentrations on uranium sorption efficiency as well as the desorbing of U(VI). The sorption of uranium on Fe(3)O(4)@SiO(2) composite particles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium can be reached within 180 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 20-200 mg/L. The maximum uranium sorption capacity onto magnetic Fe(3)O(4)@SiO(2) composite particles was estimated to be about 52 mg/g at 25 °C. The highest values of uranium desorption (98%) was achieved using 0.01 M HCl as the desorbing agent. Fe(3)O(4)@SiO(2) composite particles showed a good selectivity for uranium from aqueous solution with other interfering cation ions. Present study suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

Preparation and drug-loading properties of Fe{sub 3}O{sub 4}/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Lu, Wensheng [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China); Shen, Yuhua, E-mail: s_yuhua@163.com [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Xie, Anjian [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Zhang, Weiqiang [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China)

2013-11-15

Fe{sub 3}O{sub 4}/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe{sub 3}O{sub 4} nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50–120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe{sub 3}O{sub 4} nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

Efficient reduced graphene oxide grafted porous Fe3O4 composite as a high performance anode material for Li-ion batteries.

Science.gov (United States)

Bhuvaneswari, Subramani; Pratheeksha, Parakandy Muzhikara; Anandan, Srinivasan; Rangappa, Dinesh; Gopalan, Raghavan; Rao, Tata Narasinga

2014-03-21

Here, we report facile fabrication of Fe3O4-reduced graphene oxide (Fe3O4-RGO) composite by a novel approach, i.e., microwave assisted combustion synthesis of porous Fe3O4 particles followed by decoration of Fe3O4 by RGO. The characterization studies of Fe3O4-RGO composite demonstrate formation of face centered cubic hexagonal crystalline Fe3O4, and homogeneous grafting of Fe3O4 particles by RGO. The nitrogen adsorption-desorption isotherm shows presence of a porous structure with a surface area and a pore volume of 81.67 m(2) g(-1), and 0.106 cm(3) g(-1) respectively. Raman spectroscopic studies of Fe3O4-RGO composite confirm the existence of graphitic carbon. Electrochemical studies reveal that the composite exhibits high reversible Li-ion storage capacity with enhanced cycle life and high coulombic efficiency. The Fe3O4-RGO composite showed a reversible capacity ∼612, 543, and ∼446 mA h g(-1) at current rates of 1 C, 3 C and 5 C, respectively, with a coulombic efficiency of 98% after 50 cycles, which is higher than graphite, and Fe3O4-carbon composite. The cyclic voltammetry experiment reveals the irreversible and reversible Li-ion storage in Fe3O4-RGO composite during the starting and subsequent cycles. The results emphasize the importance of our strategy which exhibited promising electrochemical performance in terms of high capacity retention and good cycling stability. The synergistic properties, (i) improved ionic diffusion by porous Fe3O4 particles with a high surface area and pore volume, and (ii) increased electronic conductivity by RGO grafting attributed to the excellent electrochemical performance of Fe3O4, which make this material attractive to use as anode materials for lithium ion storage.

Facile preparation of magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu composites as high performance Fenton-like catalysts

Energy Technology Data Exchange (ETDEWEB)

Li, Keyan; Zhao, Yongqin [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Janik, Michael J. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Song, Chunshan [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Guo, Xinwen, E-mail: guoxw@dlut.edu.cn [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)

2017-02-28

Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining tartrate under N{sub 2}. • Fe{sub 3}O{sub 4}/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe{sub 2}O{sub 3}/CuO and α-Fe{sub 2}O{sub 3}/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining the tartrate precursor under N{sub 2} atmosphere at 500 °C. The Fe{sub 3}O{sub 4}/C/Cu composite possessed mesoporous structure and large surface area up to 133 m{sup 2} g{sup −1}. The Fenton catalytic performance of Fe{sub 3}O{sub 4}/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe{sup 3+} to Fe{sup 2+}, which accelerated the Fe{sup 3+}/Fe{sup 2+} cycles and favored H{sub 2}O{sub 2} decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe{sup 3+} and Cu{sup 2+}, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe{sub 3}O{sub 4}/C/Cu-H{sub 2}O{sub 2} system, and MB (100 mg L{sup −1}) was nearly removed within 60 min. The Fe{sub 3}O{sub 4}/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile

Fe{sub 3}O{sub 4}@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes

Energy Technology Data Exchange (ETDEWEB)

He, Guangyu [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu, Weifeng; Sun, Xiaoqiang [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Chen, Qun, E-mail: chenqunjpu@yahoo.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Wang, Xin [Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen, Haiqun, E-mail: hqchenyf@hotmail.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China)

2013-05-15

Highlights: ► The Fe{sub 3}O{sub 4}@GO composite was prepared by a facile co-precipitation method. ► Fe{sub 3}O{sub 4} nanoparticles are well distributed on GO nanosheets. ► Fe{sub 3}O{sub 4}@GO was for the first time explored as a catalyst to reduce nitroarenes. ► Fe{sub 3}O{sub 4}@GO exhibits higher catalytic activity. ► The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe{sub 3}O{sub 4}@graphene oxide (Fe{sub 3}O{sub 4}@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N{sub 2} adsorption–desorption measurements. The results demonstrated that the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe{sub 3}O{sub 4}@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min{sup −1}, forty five times that of the commercial Fe{sub 3}O{sub 4} NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability.

Fabrication of hierarchical graphene@Fe3O4@SiO2@polyaniline quaternary composite and its improved electrochemical performance

International Nuclear Information System (INIS)

Wang, Lei; Zhu, Jianfeng; Yang, Haibo; Wang, Fen; Qin, Yi; Zhao, Ting; Zhang, Pei

2015-01-01

Highlights: • Graphene@Fe 3 O 4 @SiO 2 @polyaniline hierarchical structures have been fabricated. • The reflection loss of the composites is below −10 dB in 10.5–16.3 GHz. • The maximum absorption of the composites is −40.7 dB at 12.5 GHz. - Abstract: Hierarchical graphene@Fe 3 O 4 @SiO 2 @polyaniline quaternary composite is fabricated subtly. Their microwave absorption properties are also investigated in the 2–18 GHz frequency range. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) reveal that Fe 3 O 4 @SiO 2 @polyaniline core@shell@shell heteronanostructures are densely covered on the surfaces of graphene, and form hierarchical structures. Compared with two-dimensional binary nanocomposites of graphene@Fe 3 O 4 , the hierarchical structure exhibits enhanced EM absorption in terms of both the maximum reflection loss value and the absorption bandwidth. The maximum reflection loss value can reach −40.7 dB at 12.5 GHz with a thickness of 2.5 mm and the bandwidth corresponding to the reflection loss below −10 dB is 5.8 GHz (from 10.5 to 16.3 GHz)

Facile synthesis of Fe3O4/g-C3N4/HKUST-1 composites as a novel biosensor platform for ochratoxin A.

Science.gov (United States)

Hu, Shuisheng; Ouyang, Wenjun; Guo, Longhua; Lin, Zhenyu; Jiang, Xiaohua; Qiu, Bin; Chen, Guonan

2017-06-15

A fluorescent biosensor for ochratoxin A was fabricated on the basis of a new nanocomposite (Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites). Fe 3 O 4 /g-C 3 N 4 /HKUST-1 was synthesized in this work for the first time, which combined HKUST-1 with g-C 3 N 4 to improve its chemical stability. Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites have strong adsorption capacity for dye-labeled aptamer and are able to completely quench the fluorescence of the dye through the photoinduced electron transfer (PET) mechanism. In the presence of ochratoxin A (OTA), it can bind with the aptamer with high affinity, causing the releasing of the dye-labeled aptamer from the Fe 3 O 4 /g-C 3 N 4 /HKUST-1 and therefore results in the recovery of fluorescence. The fluorescence intensity of the biosensor has a linear relationship with the OTA concentration in the range of 5.0-160.0ng/mL. The LOD of sensor is 2.57ng/mL (S/N=3). This fluorescence sensor based on the Fe 3 O 4 /g-C 3 N 4 /HKUST-1 composites has been applied to detect OTA in corn with satisfying results. Copyright © 2016. Published by Elsevier B.V.

Fe3O4@Au composite magnetic nanoparticles modified with cetuximab for targeted magneto-photothermal therapy of glioma cells.

Science.gov (United States)

Lu, Qianling; Dai, Xinyu; Zhang, Peng; Tan, Xiao; Zhong, Yuejiao; Yao, Cheng; Song, Mei; Song, Guili; Zhang, Zhenghai; Peng, Gang; Guo, Zhirui; Ge, Yaoqi; Zhang, Kangzhen; Li, Yuntao

2018-01-01

Thermoresponsive nanoparticles have become an attractive candidate for designing combined multimodal therapy strategies because of the onset of hyperthermia and their advantages in synergistic cancer treatment. In this paper, novel cetuximab (C225)-encapsulated core-shell Fe 3 O 4 @Au magnetic nanoparticles (Fe 3 O 4 @Au-C225 composite-targeted MNPs) were created and applied as a therapeutic nanocarrier to conduct targeted magneto-photothermal therapy against glioma cells. The core-shell Fe 3 O 4 @Au magnetic nanoparticles (MNPs) were prepared, and then C225 was further absorbed to synthesize Fe 3 O 4 @Au-C225 composite-targeted MNPs. Their morphology, mean particle size, zeta potential, optical property, magnetic property and thermal dynamic profiles were characterized. After that, the glioma-destructive effect of magnetic fluid hyperthermia (MFH) combined with near-infrared (NIR) hyperthermia mediated by Fe 3 O 4 @Au-C225 composite-targeted MNPs was evaluated through in vitro and in vivo experiments. The inhibitory and apoptotic rates of Fe 3 O 4 @Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group were significantly higher than other groups in vitro and the marked upregulation of caspase-3, caspase-8, and caspase-9 expression indicated excellent antitumor effect by inducing intrinsic apoptosis. Furthermore, Fe 3 O 4 @Au-C225 composite-targeted MNPs-mediated combined hyperthermia (MFH+NIR) group exhibited significant tumor growth suppression compared with other groups in vivo. Our studies illustrated that Fe 3 O 4 @Au-C225 composite-targeted MNPs have great potential as a promising nanoplatform for human glioma therapy and could be of great value in medical use in the future.

Fe2O3/Reduced Graphene Oxide/Fe3O4 Composite in Situ Grown on Fe Foil for High-Performance Supercapacitors.

Science.gov (United States)

Zhao, Chongjun; Shao, Xiaoxiao; Zhang, Yuxiao; Qian, Xiuzhen

2016-11-09

A Fe 2 O 3 /reduced graphene oxide (RGO)/Fe 3 O 4 nanocomposite in situ grown on Fe foil was synthesized via a simple one-step hydrothermal growth process, where the iron foil served as support, reductant of graphene oxide, Fe source of Fe 3 O 4 , and also the current collector of the electrode. When it directly acted as the electrode of a supercapacitor, as-synthesized Fe 2 O 3 /RGO/Fe 3 O 4 @Fe exhibited excellent electrochemical performance with a high capability of 337.5 mF/cm 2 at 20 mA/cm 2 and a superior cyclability with 2.3% capacity loss from the 600th to the 2000th cycle.

Efficient removal of arsenic by strategically designed and layer-by-layer assembled PS@+rGO@GO@Fe3O4 composites.

Science.gov (United States)

Kang, Bong Kyun; Lim, Byeong Seok; Yoon, Yeojoon; Kwag, Sung Hoon; Park, Won Kyu; Song, Young Hyun; Yang, Woo Seok; Ahn, Yong-Tae; Kang, Joon-Wun; Yoon, Dae Ho

2017-10-01

The PS@+rGO@GO@Fe 3 O 4 (PG-Fe 3 O 4 ) hybrid composites for Arsenic removal were successfully fabricated and well dispersed using layer-by-layer assembly and a hydrothermal method. The PG-Fe 3 O 4 hybrid composites were composed of uniformly coated Fe 3 O 4 nanoparticles on graphene oxide layers with water flow space between 3D structures providing many contact area and adsorption sites for Arsenic adsorption. The PG-Fe 3 O 4 hybrid composite has large surface adsorption sites and exhibits high adsorption capacities of 104 mg/g for As (III) and 68 mg/g for As (V) at 25 °C and pH 7 comparison with pure Fe 3 O 4 and P-Fe 3 O 4 samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composited reduced graphene oxide into LiFePO4/Li2SiO3 and its electrochemical impedance spectroscopy properties

Science.gov (United States)

Arifin, M.; Rus, Y. B.; Aimon, A. H.; Iskandar, F.; Winata, T.; Abdullah, M.; Khairurrijal, K.

2017-03-01

LiFePO4 is commonly used as cathode material for Li-ion batteries due to its stable operational voltage and high specific capacity. However, it suffers from certain disadvantages such as low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to analyse the effect of reduced graphene oxide (rGO) on the electrochemical properties of LiFePO4/Li2SiO3 composite. This composite was synthesized by a hydrothermal method. Fourier transform infrared spectroscopy measurement identified the O-P-O, Fe-O, P-O, and O-Si-O- bands in the LiFePO4/Li2SiO3 composite. X-ray diffraction measurement confirmed the formation of LiFePO4. Meanwhile, Raman spectroscopy confirmed the number of rGO layers. Further, scanning electron microscopy images showed that rGO was distributed around the LiFePO4/Li2SiO3 particles. Finally, the electrochemical impedance spectroscopy results showed that the addition of 1 wt% of rGO to the LiFePO4/Li2SiO3 composite reduced charge transfer resistance. It may be concluded that the addition of 1 wt% rGO to LiFePO4/Li2SiO3 composite can enhance its electrochemical performance as a cathode material.

Magnetism and Microwave Absorption Properties of Fe3O4 Microflake-Paraffin Composites Without and With Magnetic Orientation

Science.gov (United States)

Wang, Peng; Zhang, Junming; Chen, Yuanwei; Wang, Guowu; Wang, Dian; Wang, Tao; Li, Fashen

2018-01-01

We have synthesized thin Fe3O4 microflakes by a simple hydrothermal method and prepared Fe3O4 microflake-paraffin composites without and with magnetic orientation using the method of simple ultrasonic mixing and rotating samples in a magnetic field. X-ray diffractometer, Mössbauer spectrum, scanning electron microscope and vibrating sample magnetometer were used to characterize the samples. The complex permittivity and permeability of Fe3O4 microflake-paraffin composites without and with magnetic orientation were measured in the frequency range of 0.1-18 GHz by a vector network analyzer using a coaxial method. The reflection loss (RL) was calculated by the measured electromagnetic parameters using transmission line theory. The measurement of electromagnetic parameters shows that magnetic orientation makes the complex permittivity and permeability increase. The calculated RL shows that the Fe3O4 microflake-paraffin composite with magnetic orientation has enhanced microwave absorption properties in the frequency range of 1-3 GHz and the thickness range of 2.9-3.5 mm, indicating that the Fe3O4 microflake-paraffin composite with magnetic orientation is a promising thin microwave absorption material in the L-S band.

The microwave absorbing properties of ZnO/Fe3O4/paraffin composites in low frequency band

Science.gov (United States)

Yin, Pengfei; Deng, Yu; Zhang, Limin; Huang, Juan; Li, Huayao; Li, Youhongyu; Qi, Yali; Tao, Yu

2018-02-01

ZnO/Fe3O4/paraffin composites with good microwave absorption performance in low frequency band were prepared by physical blending technology. The morphology, phase structures, frequency-dependent electromagnetic and microwave absorbing properties of the composites were investigated. The results showed that the addition content of ZnO can adjust the microwave absorbing properties i.e. the position, intensity, and absorption bandwidth of composites, and the synergetic consequence of dielectric loss and magnetic loss is the main microwave absorption mechanism of the composites. The bandwidths with RL below -10 dB over different frequency ranges were obtained in the low frequency range of 0.5 ˜ 3 GHz at a thickness of 5 mm, e.g. 0.93 GHz from 1.59 to 2.52 GHz and 0.85 GHz from 1.26 to 2.11 GHz corresponding to the mass ratios of ZnO and Fe3O4 are 1:2 and 1:4, respectively. Thus, such absorbers can be applied as effective microwave absorbers in low frequency range of 0.5 ˜ 3 GHz.

A facile method for preparing porous, optically active, magnetic Fe3 O4 @poly(N-acryloyl-leucine) inverse core/shell composite microspheres.

Science.gov (United States)

Liu, Dong; Deng, Jianping; Yang, Wantai

2014-01-01

The first synthesis of porous, optically active, magnetic Fe3 O4 @poly(N-acryloyl-leucine) inverse core/shell composite microspheres is reported, in which the core is constructed of chiral polymer and the shell is constructed of Fe3 O4 NPs. The microspheres integrate three significant concepts, "porosity", "chirality", and "magneticity", in one single microspheric entity. The microspheres consist of Fe3 O4 nanoparticles and porous optically active microspheres, and thus combine the advantages of both magnetic nanoparticles and porous optically active microspheres. The pore size and specific surface area of the microspheres are characterized by N2 adsorption, from which it is found that the composite microspheres possess a desirable porous structure. Circular dichroism and UV-vis absorption spectroscopy measurements demonstrate that the microspheres exhibit the expected optical activity. The microspheres also have high saturation magnetization of 14.7 emu g(-1) and rapid magnetic responsivity. After further optimization, these novel microspheres may potentially find applications in areas such as asymmetric catalysis, chiral adsorption, etc. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposited Mn3O4-NiO-Co3O4 as a composite electrode material for electrochemical capacitor

International Nuclear Information System (INIS)

Rusi; Majid, S.R.

2015-01-01

Highlights: • Composite electrodes were synthesized by in situ electrodeposition method. • The highest specific capacitance of composite electrode is 7404 F g −1 . • The power density of composite electrode is 99 kW kg −1 at current density of 20 A g −1 . • The addition of K 3 Fe(CN) 6 in KOH electrolyte has improved the electrochemical performance. - Abstract: A simple and easy galvanostatic electrodeposition method is used to synthesise a composite electrode consisting of manganese oxide (Mn 3 O 4 ), nickel oxide (NiO) and cobalt oxide (Co 3 O 4 ). The influence of Co 3 O 4 on the morphology of fixed Mn 3 O 4 -NiO particles is investigated with a field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The nature and elemental of the composite are examined by means of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The electrochemical performances of an Mn 3 O 4 -NiO-Co 3 O 4 nanostructure/SS composite electrode are studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (CD) in various electrolytes, i.e. 0.5 M Na 2 SO 4 , 0.5 M KOH, 0.5 M Na 2 SO 4 /0.04 M K 3 Fe(CN) 6 and 0.5 M KOH/0.04 M K 3 Fe(CN) 6 electrolytes. The composite electrode prepared from 0.15 M Co deposition solution exhibits the optimum specific capacitance of 7404 F g −1 with high energy and power density of 1028 Wh kg −1 and 99 kW kg −1 at 20 A g −1 in mix KOH/0.04 M K 3 Fe(CN) 6 electrolyte, respectively. The results show that the incorporation of K 3 Fe(CN) 6 in KOH electrolyte influences the capacitance of Mn 3 O 4 -NiO-Co 3 O 4 composite electrodes

Biocompatibility of Fe3O4@Au composite magnetic nanoparticles in vitro and in vivo

Directory of Open Access Journals (Sweden)

Li Y

2011-11-01

Full Text Available Yuntao Li1,2, Jing Liu1, Yuejiao Zhong3, Jia Zhang1, Ziyu Wang1, Li Wang1, Yanli An1, Mei Lin1, Zhiqiang Gao2, Dongsheng Zhang11School of Medicine, Southeast University, Nanjing, Jiangsu Province, People's Republic of China; 2Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China; 3Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research, Nanjing, Jiangsu Province, People's Republic of ChinaPurpose: This research was conducted to assess the biocompatibility of the core-shell Fe3O4@Au composite magnetic nanoparticles (MNPs, which have potential application in tumor hyperthermia. Methods: Fe3O4@Au composite MNPs with core-shell structure were synthesized by reduction of Au3+ in the presence of Fe3O4-MNPs prepared by improved co-precipitation. Cytotoxicity assay, hemolysis test, micronucleus (MN assay, and detection of acute toxicity in mice and beagle dogs were then carried out.Results: The result of cytotoxicity assay showed that the toxicity grade of this material on mouse fibroblast cell line (L-929 was classified as grade 1, which belongs to no cytotoxicity. Hemolysis rates showed 0.278%, 0.232%, and 0.197%, far less than 5%, after treatment with different concentrations of Fe3O4@Au composite MNPs. In the MN assay, there was no significant difference in MN formation rates between the experimental groups and negative control (P > 0.05, but there was a significant difference between the experimental groups and the positive control (P < 0.05. The median lethal dose of the Fe3O4@Au composite MNPs after intraperitoneal administration in mice was 8.39 g/kg, and the 95% confidence interval was 6.58-10.72 g/kg, suggesting that these nanoparticles have a wide safety margin. Acute toxicity testing in beagle dogs also showed no significant difference in body weight between the treatment groups at 1, 2, 3, and 4 weeks after liver injection and no behavioral changes. Furthermore, blood

Graphene oxide-Fe{sub 3}O{sub 4} nanoparticle composite with high transverse proton relaxivity value for magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Venkatesha, N.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Poojar, Pavan; Geethanath, Sairam [Medical Imaging Research Centre, Dayananda Sagar Institutions, Bangalore 560078 (India); Qurishi, Yasrib [Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012 (India)

2015-04-21

The potential of graphene oxide–Fe{sub 3}O{sub 4} nanoparticle (GO-Fe{sub 3}O{sub 4}) composite as an image contrast enhancing material in magnetic resonance imaging has been investigated. Proton relaxivity values were obtained in three different homogeneous dispersions of GO-Fe{sub 3}O{sub 4} composites synthesized by precipitating Fe{sub 3}O{sub 4} nanoparticles in three different reaction mixtures containing 0.01 g, 0.1 g, and 0.2 g of graphene oxide. A noticeable difference in proton relaxivity values was observed between the three cases. A comprehensive structural and magnetic characterization revealed discrete differences in the extent of reduction of the graphene oxide and spacing between the graphene oxide sheets in the three composites. The GO-Fe{sub 3}O{sub 4} composite framework that contained graphene oxide with least extent of reduction of the carboxyl groups and largest spacing between the graphene oxide sheets provided the optimum structure for yielding a very high transverse proton relaxivity value. It was found that the GO-Fe{sub 3}O{sub 4} composites possessed good biocompatibility with normal cell lines, whereas they exhibited considerable toxicity towards breast cancer cells.

Highly efficient enrichment of low-abundance intact proteins by core-shell structured Fe3O4-chitosan@graphene composites.

Science.gov (United States)

Zhang, Peng; Fang, Xiaoni; Yan, Guoquan; Gao, Mingxia; Zhang, Xiangmin

2017-11-01

In proteomics research, the screening and monitoring of disease biomarkers is still a major challenge, mainly due to their low concentration in biological samples. However, the universal enrichment of intact proteins has not been further studied. In this work, we developed a Fe 3 O 4 -chitosan@graphene (Fe 3 O 4 -CS@G) core-shell composite to enrich low-abundance proteins from biological samples. Fe 3 O 4 -CS@G composite holds chitosan layer decorated Fe 3 O 4 core, which improves the hydrophilicity of materials greatly. Meanwhile, the graphene nanosheets shell formed via electrostatic assembly endows the composite with huge surface area (178m 2 /g). The good water dispersibility ensures the sufficient contact opportunities between graphene composites and proteins, and the large surface area provides enough adsorption sites for the enrichment of proteins. Using Fe 3 O 4 -CS@G, four standard proteins Cyt-c, BSA, Myo and OVA were enriched with better adsorption capacity and recovery rate, compared with previously reported magnetic graphene composites. Additionally, the mechanism of compared to" is corrected into "compared with". proteins adsorption on Fe 3 O 4 -CS@G was further studied, which indicates that hydrophobic and electrostatic interaction work together to facilitate the universal and efficient enrichment of proteins. Human plasma sample was employed to further evaluate the enrichment performance of Fe 3 O 4 -CS@G. Eventually, 123 proteins were identified from one of SAX fractions of human plasma, which is much better than commercial Sep-pak C18 enrichment column (39 proteins). All these outstanding performances suggest that Fe 3 O 4 -CS@G is an ideal platform for the enrichment of low-abundance intact proteins and thus holds great potential to facilitate the identification of biomarkers from biological samples in proteomics research. Copyright © 2017 Elsevier B.V. All rights reserved.

Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

Directory of Open Access Journals (Sweden)

Shams Ali Baig

Full Text Available The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C and environment (air and nitrogen were investigated for the adsorptive removal of As(V and As(III from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4 via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2>Fe3O4-HBC (uncalcined>Fe3O4-HBC-400°C(N2>Fe3O4-HBC-400°C(air>Fe3O4-HBC-1000°C(air and the maximum As(V and As(III adsorption capacities were found to be about 3.35 mg g(-1 and 3.07 mg g(-1, respectively. The adsorption of As(V and As(III remained stable in a wider pH range (4-10 using Fe3O4-HBC-1000°C(N2. Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99 rather than pseudo-first-order kinetics model. The adsorption of As(V and As(III onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher strongly inhibited As(V and As(III removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

Science.gov (United States)

Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

2014-01-01

The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g(-1) and 3.07 mg g(-1), respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

Fabrication and magnetic-induced aggregation of Fe3O4–noble metal composites for superior SERS performances

International Nuclear Information System (INIS)

Gan, Zibao; Zhao, Aiwu; Zhang, Maofeng; Wang, Dapeng; Guo, Hongyan; Tao, Wenyu; Gao, Qian; Mao, Ranran; Liu, Erhu

2013-01-01

Fe 3 O 4 –noble metal composites were obtained by combining Au, Ag nanoparticles (NPs) with 3-aminopropyltrimethoxysilane-functionalized Fe 3 O 4 NPs. UV–Visible absorption spectroscopy demonstrates the obtained Fe 3 O 4 –noble metal composites inherit the typical surface plasmon resonance bands of Au, Ag at 533 and 453 nm, respectively. Magnetic measurements also indicated that the superparamagnetic Fe 3 O 4 –noble metal composites have excellent magnetic response behavior. A magnetic-induced idea was introduced to change their aggregated states and take full advantage of their surface-enhanced Raman scattering (SERS) performances. Under the induction of an external magnetic field, the bifunctional Fe 3 O 4 –noble metal aggregates exhibit the unique superiority in SERS detection of Rhodamine 6G (R6G), compared with the naturally dispersed Au, Ag NPs. Especially, the detection limit of the Fe 3 O 4 –Ag aggregates for R6G is as low as 10 −14  M, and the calculated EF reaches up to 1.2 × 10 6 , which meets the requirements for trace detection of analytes. Furthermore, the superiority could be extended to sensitive detection of other organic molecules, such as 4-mercaptopyridine. This work provides a new insight for active adjustment of the aggregated states of SERS substrates and the optimization of SERS performances

Facile Synthesis of CeO2-LaFeO3 Perovskite Composite and Its Application for 4-(Methylnitrosamino-1-(3-Pyridyl-1-Butanone (NNK Degradation

Directory of Open Access Journals (Sweden)

Kaixuan Wang

2016-04-01

Full Text Available A facile and environmentally friendly surface-ion adsorption method using CeCO3OH@C as template was demonstrated to synthesize CeO2-LaFeO3 perovskite composite material. The obtained composite was characterized by X-ray diffraction (XRD, fourier transform infrared spectra (FT-IR, field-emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, thermo-gravimetric analysis and differential scanning calorimetry (TG-DSC, N2 adsorption/desorption isotherms and X-ray photoelectron spectra (XPS measurements. The catalytic degradation of nitrosamine 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK was tested to evaluate catalytic activity of the CeO2-LaFeO3 composite. Much better activity was observed for the CeO2-LaFeO3 composite comparing with CeO2 and LaFeO3. These results suggested that perovskite composite materials are a promising candidate for the degradation of tobacco-specific nitrosamines (TSNAs.

Enhanced microwave absorption property of epoxy nanocomposites based on PANI@Fe3O4@CNFs nanoparticles with three-phase heterostructure

Science.gov (United States)

Yang, Lingfeng; Cai, Haopeng; Zhang, Bin; Huo, Siqi; Chen, Xi

2018-02-01

Novel electromagnetic functionalized carbon nanofibers (CNFs) have been synthesized by coating with Fe3O4 magnetite nanoparticles and conducting polymers polyaniline (PANI) on CNFs through a layer by layer assembly. The Fe3O4@CNFs were first prepared by coating nano-Fe3O4 particles on CNFs via co-precipitation method; Then the PANI was coated on Fe3O4@CNFs using an in situ polymerization process to obtain PANI@Fe3O4@CNFs nanoparticles. The prepared PANI@Fe3O4@CNFs nanoparticles were dispersed in the epoxy matrix to fabricate microwave absorbing nanocomposites. Compared with the Fe3O4@CNFs/epoxy nanocomposites, the PANI@Fe3O4@CNFs/epoxy nanocomposites exhibit better microwave absorbing properties. The composite containing 15 wt% of PANI@Fe3O4@CNFs with the thickness of 2 mm showed a minimum reflection loss (RL) value of -23.7 dB with an effective absorption bandwidth which is about 3.7 GHz (11.9-15.6 GHz) in the frequency range of 1-18 GHz, indicating that it is an attractive candidate for efficient microwave absorber. A potential absorption mechanism was proposed for enhancement of the impedance-matching condition and electromagnetic wave-attenuation characteristic of materials. Specifically, the impedance-matching condition was improved by the combination of conductive polymers and magnetic nanoparticles with CNFs. The electromagnetic wave attenuation characteristic was enhanced by multiple reflections, due to the increased propagation paths.

Synthesis of novel spherical Fe_3O_4@Ni_3S_2 composite as improved anode material for rechargeable nickel-iron batteries

International Nuclear Information System (INIS)

Li, Jing; Guo, Litan; Shangguan, Enbo; Yue, Mingzhu; Xu, Min; Wang, Dong; Chang, Zhaorong; Li, Quanmin

2017-01-01

Highlights: • Fe_3O_4@Ni_3S_2 microspheres are fabricated through a facile method for the first time. • Fe_3O_4@Ni_3S_2 is firstly proposed as alkaline anode materials for Ni/Fe batteries. • Fe_3O_4@Ni_3S_2 shows enhanced high-rate capability and improved cycle stability. • Ni_3S_2 can suppress the passivation and hydrogen evolution behavior of the iron anode. - Abstract: Fe_3O_4@Ni_3S_2 microspheres as a novel alkaline anode material have been successfully fabricated through a four-step process for the first time. In this composite, Ni_3S_2 nanoparticles are coated tightly on the surface of Fe_3O_4 microspheres. Compared with the pure Fe_3O_4 and Fe_3O_4@NiO microspheres, the proposed Fe_3O_4@Ni_3S_2 delivers a significantly improved high-rate performance and enhanced cycling stability. At a high discharge rate of 1200 mA g"−"1, the specific capacity of the Fe_3O_4@Ni_3S_2 is ∼481.2 mAh g"−"1 in comparison with ∼83.7 mAh g"−"1 for the pure Fe_3O_4. After 100 cycles at 120 mA g"−"1, the Fe_3O_4@Ni_3S_2 can achieve a capacity retention of 95.1%, while the value for the pure Fe_3O_4 electrode is only 52.5%. The favorable electrochemical performance of the Fe_3O_4@Ni_3S_2 is mainly attributed to the beneficial impact of Ni_3S_2. The Ni_3S_2 layer as a useful additive is significantly conducive to lessening the formation of Fe(OH)_2 passivation layer, enhancing the electronic conductivity, improving the reaction reversibility and suppressing the hydrogen evolution reaction of the alkaline iron anode. Owing to its outstanding electrochemical properties, we believe that the novel Fe_3O_4@Ni_3S_2 composite is potentially a promising candidate for anode material of alkaline iron-based batteries.

Investigation of P(VDF-TrFE)/ZrO{sub 2}-MMA polymer composites applied to radiation shielding

Energy Technology Data Exchange (ETDEWEB)

Fontainha, C.C.P. [Depto. de Engenharia Nuclear - UFMG, Av. Antonio Carlos 6627, 31270-970 Belo Horizonte, MG (Brazil); Baptista Neto, A.T.; Santos, A.P.; Faria, L.O. [Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antonio Carlos 6627, C.P. 941, 30270-901, Belo Horizonte, MG (Brazil)

2015-07-01

Exposure to high radiation dose in medical diagnostic imaging procedures can lead patients to suffer tissue damaging. However, there are several studies that identify significant dose reduction with the use of radiation protective attenuators, minimizing the delivered dose in the region that covers the main beam, while preserving the diagnostic quality of the generated image. Most radiation attenuator materials are produced from shielding metal containing composites, whose efficiency is the goal of investigations around the world. In this context, polymeric materials were chosen for this investigation in order to provide light-weighted and flexible protective composites, a must in personal protective shielding. Therefore, this work is concerned to the investigation of poly(vinylidene fluoride - try-fluor-ethylene) [P(VDF-TrFE)] copolymers mixed with zirconia nanoparticles. The resulting polymer composites, prepared with 1, 2, 3, 5 and 10 at.% of ZrO{sub 2} nanoparticles, were investigated for application as protective shielding in some interventional radiology procedures. Two variety of composites were produced, one using pure ZrO{sub 2} nanoparticles and the other using sol-gel route with zirconium butoxide as the precursor for zirconium oxide nano-clusters. The P(VDFTrFE)/ ZrO2-MMA polymer composites produced by sol-gel route have provided a much better dispersion of the pure ZrO{sub 2} material into the P(VDF-TrFE) host matrix. UV-Vis and FTIR spectrometry and differential scanning calorimetry (DSC) were used to characterize the composite samples. FTIR data reveal a possible link between the MMA monomers with the P(VDF-TrFE) chain through shared C=O bonds. The radiation shielding characterization was conducted by using a 70 kV x-rays beam which is applicable, for instances, in catheter angiography. The results demonstrate that composites with 10% of ZrO{sub 2}, and only 1.0 mm thick, can attenuate 60% of the x-rays beam. The composite density was evaluated to be

Highly stable and magnetically separable alginate/Fe3O4 composite for the removal of strontium (Sr) from seawater.

Science.gov (United States)

Hong, Hye-Jin; Jeong, Hyeon Su; Kim, Byoung-Gyu; Hong, Jeongsik; Park, In-Su; Ryu, Taegong; Chung, Kang-Sup; Kim, Hyuncheol; Ryu, Jungho

2016-12-01

In this study, a highly stable alginate/Fe 3 O 4 composite was synthesized, and systematically investigated for the practical application of strontium (Sr) removal in complex media, such as seawater and radioactive wastewater. To overcome the drawbacks of the use of alginate microspheres, high contents of alginic acid and Fe 3 O 4 were used to provide a more rigid structure with little swelling and facile separation, respectively. The synthesized composite was optimized for particle sizes of seawater spiked with 50 mg/L of Sr, the alginate/Fe 3 O 4 composite showed 12.5 mg/g of Sr uptake, despite the highly concentrated ions in seawater. The adsorption experiment for radio-active 90 Sr revealed a removal efficiency of 67% in real seawater, demonstrating the reliability of the alginate/Fe 3 O 4 composite. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis of Fe3O4 cluster microspheres/graphene aerogels composite as anode for high-performance lithium ion battery

Science.gov (United States)

Zhou, Shuai; Zhou, Yu; Jiang, Wei; Guo, Huajun; Wang, Zhixing; Li, Xinhai

2018-05-01

Iron oxides are considered as attractive electrode materials because of their capability of lithium storage, but their poor conductivity and large volume expansion lead to unsatisfactory cycling stability. We designed and synthesized a novel Fe3O4 cluster microspheres/Graphene aerogels composite (Fe3O4/GAs), where Fe3O4 nanoparticles were assembled into cluster microspheres and then embedded in 3D graphene aerogels framework. In the spheres, the sufficient free space between Fe3O4 nanoparticles could accommodate the volume change during cycling process. Graphene aerogel works as flexible and conductive matrix, which can not only significantly increase the mechanical stress, but also further improve the storage properties. The Fe3O4/GAs composite as an anode material exhibits high reversible capability and excellent cyclic capacity for lithium ion batteries (LIBs). A reversible capability of 650 mAh g-1 after 500 cycles at a current density of 1 A g-1 can be maintained. The superior storage capabilities of the composites make them potential anode materials for LIBs.

Study of cerium doped magnetite (Fe 3O 4:Ce)/PMMA nanocomposites

Science.gov (United States)

Padalia, Diwakar; Johri, U. C.; Zaidi, M. G. H.

2012-03-01

The paper presents the synthesis and properties of polymer nanocomposite material based on cerium doped magnetite (Fe 3O 4) as filler material and poly methyl methacrylate (PMMA) as host matrix. The magnetite (Fe 3O 4) particles were synthesized by co-precipitation route using stable ferrous and ferric salts with ammonium hydroxide as precipitating agent. Further, they doped by cerium oxide (CeO 2) non-stoichiometrically. The composite material was fabricated by solvent evaporation method. Here 2.4 GHz microwaves were used to study the effect of microwaves heating on polymerization. The phase and crystal structure is determined by X-ray diffraction (XRD). The average crystallite size of the composites varies from 28 to 35 nm. The chemical structure is confirmed by Fourier transform infrared (FTIR) spectroscopy. The magnetic and thermal properties are investigated by vibrating sample magnetometer (VSM) and differential scanning calorimetry (DSC). The thermal study shows that the microwave heated samples possess higher glass transition temperature ( Tg). The magnetic results suggest that coercivity ( HC) and squareness ( Mr/ Ms) of the loop increases with increasing doping percent of cerium.

Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

International Nuclear Information System (INIS)

Hu Yong; Li Jing-Chao; Shen Ming-Wu; Shi Xiang-Yang

2014-01-01

Recent advances with iron oxide/gold (Fe 3 O 4 /Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe 3 O 4 /Au CNPs is introduced. Potential applications of some developed Fe 3 O 4 /Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail. (topical review - magnetism, magnetic materials, and interdisciplinary research)

Magnetic biodegradable Fe3O4/CS/PVA nanofibrous membranes for bone regeneration

International Nuclear Information System (INIS)

Wei Yan; Zhang Xuehui; Hu Xiaoyang; Deng Xuliang; Song Yu; Lin Yuanhua; Han Bing; Wang Xinzhi

2011-01-01

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe 3 O 4 /chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe 3 O 4 nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe 3 O 4 nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe 3 O 4 /CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe 3 O 4 , CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe 3 O 4 loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe 3 O 4 nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe 3 O 4 nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe 3 O 4 nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe 3 O 4 /CS/PVA nanofibrous membranes can be one of promising biomaterials for facilitation of osteogenesis.

Preparation and photoelectric properties of p-CaFe{sub 2}O{sub 4}/n-WO{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Wan, Ruiqin; Jia, Caihong [Key Laboratory of Photovoltaic Materials of Henan Province and School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Zhang, Weifeng, E-mail: wfzhang@henu.edu.cn [Key Laboratory of Photovoltaic Materials of Henan Province and School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Surface photovoltage spectroscopy investigation on p-CaFe{sub 2}O{sub 4}/n-WO{sub 3} composites. Black-Right-Pointing-Pointer The photovoltaic response is enhanced in p-CaFe{sub 2}O{sub 4}/n-WO{sub 3} composites. Black-Right-Pointing-Pointer The multielectron process and high rate of carrier migration in WO{sub 3}. - Abstract: Composites of p-CaFe{sub 2}O{sub 4}/n-WO{sub 3} are prepared via a sol-gel technique. Their structures and optical properties are characterized with X-ray diffraction, scanning electron microscopy and UV-vis absorption spectroscopy. The photoelectric characteristics are investigated by surface photovoltage spectroscopy combined with electric field induced surface photovoltage spectroscopy. The results indicate that CaFe{sub 2}O{sub 4} can well form a p-n type composite with WO{sub 3}, and the intensity and spectral region of surface photovoltaic response for the composites are strongly dependent on the molar ratio of two components. The enhancement in photoelectric properties and the effective separation of photogenerated carriers could be attributed to the energy level matching between the two components, multielectron process and the high migration rate in WO{sub 3}.

Mechanical properties, microstructure and magnetic properties of composite magnet base on SrO.6Fe_2O_3 (SRM)-thermoplastic and thermoset polymer

International Nuclear Information System (INIS)

Grace Tj Sulungbudi; Aloma Karo Karo; Mujamilah; Sudirman

2010-01-01

The use of magnets in industrial applications do not always require high magnetic properties. Therefore, the use of polymer as a matrix that serves as a binder can be applied to obtain lightweight, flexible and cheap composite magnet. This report discuss composite magnet base on SrO.6Fe_2O_3(SRM)-thermoplastic and thermoset polymer. Thermoplastic polymer consist of polypropylene (PP) type of PP2 and PP10 and polyethylene (PE) type of LDPE were used. For thermoset polymer, epoxy and polyester were used. Synthesis of composite magnet based on thermoplastic polymer (PP2, PP10, LDPE) were carried using the blending method, while the thermoset composites magnet using casting method. Thermoplastic composite magnets were prepared with compositions of 50, 41, 38, 33 and 29 % weight of SRM with the blending temperature of 160 °C for LDPE and 180 °C for PP2 and PP10. For thermoset composite magnets, the compositions were 30, 40, 50 and 60 % by weight of SRM. The mechanical test conducted include tensile strength and elongation at break. Microstructure on the surface of the composite materials were observed using SEM (Scanning Electron Microscope) and the magnetic properties were measured using VSM (Vibrating Sample Magnetometer). The SEM results showed the formation of flat shape powder particle with size of 1.6 µm. In general, the mechanical properties of polypropylene polymer composite magnet are better than that using polyethylene (LDPE) binder. For polypropylene binder PP10 is better than PP2. Magnetic properties are not significantly affected by the change of polymer or binder types. (author)

High-performance magnetic poly (arylene ether nitrile) nanocomposites: Co-modification of Fe3O4 via mussel inspired poly(dopamine) and amino functionalized silane KH550

Science.gov (United States)

Wan, Xinyi; Zhan, Yingqing; Long, Zhihang; Zeng, Guangyong; Ren, Yang; He, Yi

2017-12-01

To develop high-performance magnetic polymer composites, we reported a facial mussel-inspired way to functionalize Fe3O4 microspheres with dopamine (DA) and KH550, followed by compounding with poly (arylene ether nitrile) (PEN), to prepare functional nanocomposite films. Such mussel inspired co-modification of Fe3O4 was characterized and confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Therefore, the outstanding properties of the functionalize Fe3O4/polymer composites were obtained. With the addition of 15 wt% functionalized Fe3O4, the saturation magnetization (Ms) and dielectric permittivity of the PEN composites were increased to 12.49 emu/g and 14.3 (250 Hz), respectively, while the low dielectric loss was maintained. In addition, even the high loading content of Fe3O4 was incorporated, the functional PEN composites still exhibited high mechanical properties and thermal stability, including the significant improvement in glass transition temperature, and the same level of the tensile strength compared with neat PEN. Our work revealed that magnetic and dielectric PEN composites materials along with high comprehensive properties may be potentially used in the electromagnetic fields.

Fe3O4/C composite with hollow spheres in porous 3D-nanostructure as anode material for the lithium-ion batteries

Science.gov (United States)

Yang, Zhao; Su, Danyang; Yang, Jinping; Wang, Jing

2017-09-01

3d transition-metal oxides, especially Fe3O4, as anode materials for the lithium-ion batteries have been attracting intensive attentions in recent years due to their high energy capacity and low toxicity. A new Fe3O4/C composite with hollow spheres in porous three-dimensional (3D) nanostructure, which was synthesized by a facile solvothermal method using FeCl3·6H2O and porous spongy carbon as raw materials. The specific surface area and microstructures of composite were characterized by nitrogen adsorption-desorption isotherm method, FE-SEM and HR-TEM. A homogeneous distribution of hollow Fe3O4 spheres (diameter ranges from 120 nm to 150 nm) in the spongy carbon (pore size > 200 nm) conductive 3D-network significantly reduced the lithium-ion diffusion length and increased the electrochemical reaction area, and further more enhanced the lithium ion battery performance, such as discharge capacity and cycle life. As an anode material for the lithium-ion battery, the title composite exhibit excellent electrochemical properties. The Fe3O4/C composite electrode achieved a relatively high reversible specific capacity of 1450.1 mA h g-1 in the first cycle at 100 mA g-1, and excellent rate capability (69% retention at 1000 mA g-1) with good cycle stability (only 10% loss after 100 cycles).

Structural and magnetic characteristics of PVA/CoFe{sub 2}O{sub 4} nano-composites prepared via mechanical alloying method

Energy Technology Data Exchange (ETDEWEB)

Rashidi, S.; Ataie, A., E-mail: aataie@ut.ac.ir

2016-08-15

Highlights: • Single phase CoFe{sub 2}O{sub 4} nano-particles synthesized in one step by mechanical alloying. • PVA/CoFe{sub 2}O{sub 4} magnetic nano-composites were fabricated via mechanical milling. • FTIR confirmed the interaction between PVA and magnetic CoFe{sub 2}O{sub 4} particles. • Increasing in milling time and PVA amount led to well dispersion of CoFe{sub 2}O{sub 4}. - Abstract: In this research, polyvinyl alcohol/cobalt ferrite nano-composites were successfully synthesized employing a two-step procedure: the spherical single-phase cobalt ferrite of 20 ± 4 nm mean particle size was synthesized via mechanical alloying method and then embedded into polymer matrix by intensive milling. The results revealed that increase in polyvinyl alcohol content and milling time causes cobalt ferrite particles disperse more homogeneously in polymer matrix, while the mean particle size and shape of cobalt ferrite have not been significantly affected. Transmission electron microscope images indicated that polyvinyl alcohol chains have surrounded the cobalt ferrite nano-particles; also, the interaction between polymer and cobalt ferrite particles in nano-composite samples was confirmed. Magnetic properties evaluation showed that saturation magnetization, coercivity and anisotropy constant values decreased in nano-composite samples compared to pure cobalt ferrite. However, the coercivity values of related nano-composite samples enhanced by increasing PVA amount due to domain wall mechanism.

Ni doped Fe3O4 magnetic nanoparticles.

Science.gov (United States)

Larumbe, S; Gómez-Polo, C; Pérez-Landazábal, J I; García-Prieto, A; Alonso, J; Fdez-Gubieda, M L; Cordero, D; Gómez, J

2012-03-01

In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure.

Removal of UO{sup 2+}{sub 2} from aqueous solution using halloysite nanotube-Fe{sub 3}O{sub 4} composite

Energy Technology Data Exchange (ETDEWEB)

He, Wenfang; Chen, Yuantao; Zhang, Wei; Hu, Chunlian; Wang, Jian; Wang, Pingping [Qinghai Normal University, Xining (China)

2016-01-15

Halloysite nanotubes (HNTs) were modified with Fe{sub 3}O{sub 4} to form novel magnetic HNTs-Fe{sub 3}O{sub 4} composites, and the composites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The as-obtained results indicated that Fe{sub 3}O{sub 4} nanoparticles were successfully installed on the surface of HNTs. The adsorption of UO{sup 2+}{sub 2} on HNTs-Fe{sub 3}O{sub 4} was investigated as a function of solid content, contact time, pH, ionic strength and temperature by batch experiments. The consequences revealed that the adsorption of UO{sup 2+}{sub 2} onto HNTs-Fe{sub 3}O{sub 4} was strongly dependent on pH and ionic strength. Equilibrium data fitted well with the Langmuir isotherm. The experimental results demonstrated that the adsorbents with HNTs-Fe{sub 3}O{sub 4} had the largest adsorption capacity of 88.32mg/g for UO{sup 2+}{sub 2}.

Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

Science.gov (United States)

Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

2015-01-01

Fe3O4@SiO2-graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe3O4@SiO2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe3O4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe3O4@SiO2 NPs was 24 ± 0.3 nm, similar to that of Fe3O4@SiO2-NH2. Fe3O4@SiO2-GO composites were synthesized by linking of Fe3O4@SiO2-NH2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe3O4@SiO2-GO composite has potential applications in the production of bioethanol.

Study of cerium doped magnetite (Fe3O4:Ce)/PMMA nanocomposites

International Nuclear Information System (INIS)

Padalia, Diwakar; Johri, U.C.; Zaidi, M.G.H.

2012-01-01

The paper presents the synthesis and properties of polymer nanocomposite material based on cerium doped magnetite (Fe 3 O 4 ) as filler material and poly methyl methacrylate (PMMA) as host matrix. The magnetite (Fe 3 O 4 ) particles were synthesized by co-precipitation route using stable ferrous and ferric salts with ammonium hydroxide as precipitating agent. Further, they doped by cerium oxide (CeO 2 ) non-stoichiometrically. The composite material was fabricated by solvent evaporation method. Here 2.4 GHz microwaves were used to study the effect of microwaves heating on polymerization. The phase and crystal structure is determined by X-ray diffraction (XRD). The average crystallite size of the composites varies from 28 to 35 nm. The chemical structure is confirmed by Fourier transform infrared (FTIR) spectroscopy. The magnetic and thermal properties are investigated by vibrating sample magnetometer (VSM) and differential scanning calorimetry (DSC). The thermal study shows that the microwave heated samples possess higher glass transition temperature (T g ). The magnetic results suggest that coercivity (H C ) and squareness (M r /M s ) of the loop increases with increasing doping percent of cerium.

Lightweight reduced graphene oxide-Fe3O4 nanoparticle composite in the quest for an excellent electromagnetic interference shielding material

Science.gov (United States)

Singh, Ashwani Kumar; Kumar, Ajit; Kamal Haldar, Krishna; Gupta, Vinay; Singh, Kedar

2018-06-01

This work reports a detailed study of reduced graphene oxide (rGO)-Fe3O4 nanoparticle composite as an excellent electromagnetic (EM) interference shielding material in GHz range. A rGO-Fe3O4 nanoparticle composite was synthesized using a facile, one step, and modified solvothermal method with the reaction of FeCl3, ethylenediamine and graphite oxide powder in the presence of ethylene glycol. Various structural, microstructural and optical characterization tools were used to determine its synthesis and various properties. Dielectric, magnetic and EM shielding parameters were also evaluated to estimate its performance as a shielding material for EM waves. X-ray diffraction patterns have provided information about the structural and crystallographic properties of the as-synthesized material. Scanning electron microscopy micrographs revealed the information regarding the exfoliation of graphite into rGO. Well-dispersed Fe3O4 nanoparticles over the surface of the graphene can easily be seen by employing transmission electron microscopy. For comparison, rGO nanosheets and Fe3O4 nanoparticles have also been synthesized and characterized in a similar fashion. A plot of the dielectric and magnetic characterizations provides some useful information related to various losses and the relaxation process. Shielding effectiveness due to reflection (SER), shielding effectiveness due to absorption (SEA), and total shielding effectiveness (SET) were also plotted against frequency over a broad range (8–12 GHz). A significant change in all parameters (SEA value from 5 dB to 35 dB for Fe3O4 nanoparticles to rGO-Fe3O4 nanoparticle composite) was found. An actual shielding effectiveness (SET) up to 55 dB was found in the rGO-Fe3O4 nanoparticle composite. These graphs give glimpses of how significantly this material shows shielding effectiveness over a broad range of frequency.

Lightweight reduced graphene oxide-Fe3O4 nanoparticle composite in the quest for an excellent electromagnetic interference shielding material.

Science.gov (United States)

Singh, Ashwani Kumar; Kumar, Ajit; Haldar, Krishna Kamal; Gupta, Vinay; Singh, Kedar

2018-06-15

This work reports a detailed study of reduced graphene oxide (rGO)-Fe 3 O 4 nanoparticle composite as an excellent electromagnetic (EM) interference shielding material in GHz range. A rGO-Fe 3 O 4 nanoparticle composite was synthesized using a facile, one step, and modified solvothermal method with the reaction of FeCl 3 , ethylenediamine and graphite oxide powder in the presence of ethylene glycol. Various structural, microstructural and optical characterization tools were used to determine its synthesis and various properties. Dielectric, magnetic and EM shielding parameters were also evaluated to estimate its performance as a shielding material for EM waves. X-ray diffraction patterns have provided information about the structural and crystallographic properties of the as-synthesized material. Scanning electron microscopy micrographs revealed the information regarding the exfoliation of graphite into rGO. Well-dispersed Fe 3 O 4 nanoparticles over the surface of the graphene can easily be seen by employing transmission electron microscopy. For comparison, rGO nanosheets and Fe 3 O 4 nanoparticles have also been synthesized and characterized in a similar fashion. A plot of the dielectric and magnetic characterizations provides some useful information related to various losses and the relaxation process. Shielding effectiveness due to reflection (SE R ), shielding effectiveness due to absorption (SE A ), and total shielding effectiveness (SE T ) were also plotted against frequency over a broad range (8-12 GHz). A significant change in all parameters (SE A value from 5 dB to 35 dB for Fe 3 O 4 nanoparticles to rGO-Fe 3 O 4 nanoparticle composite) was found. An actual shielding effectiveness (SE T ) up to 55 dB was found in the rGO-Fe 3 O 4 nanoparticle composite. These graphs give glimpses of how significantly this material shows shielding effectiveness over a broad range of frequency.

Exchange-coupled Fe3O4/CoFe2O4 nanoparticles for advanced magnetic hyperthermia

Science.gov (United States)

Glassell, M.; Robles, J.; Das, R.; Phan, M. H.; Srikanth, H.

Iron oxide nanoparticles especially Fe3O4, γ-Fe2O3 have been extensively studied for magnetic hyperthermia because of their tunable magnetic properties and stable suspension in superparamagnetic regime. However, their relatively low heating capacity hindered practical application. Recently, a large improvement in heating efficiency has been reported in exchange-coupled nanoparticles with exchange coupling between soft and hard magnetic phases. Here, we systematically studied the effect of core and shell size on the heating efficiency of the Fe3O4/CoFe2O4 core/shell nanoparticles. The nanoparticles were synthesized using thermal decomposition of organometallic precursors. Transmission electron microscopy (TEM) showed formation of spherical shaped Fe3O4 and Fe3O-/CoFe2O4 nanoparticles. Magnetic measurements showed high magnetization (≅70 emu/g) and superparamagnetic behavior for the nanoparticles at room temperature. Magnetic hyperthermia results showed a large increase in specific absorption rate (SAR) for 8nm Fe3O4/CoFe2O4 compared to Fe3O4 nanoparticles of the same size. The heating efficiency of the Fe3O4/CoFe2O4 with 1 nm CoFe2O4 (shell) increased from 207 to 220 W/g (for 800 Oe) with increase in core size from 6 to 8 nm. The heating efficiency of the Fe3O4/CoFe2O4 with 2 nm CoFe2O4 (shell) and core size of 8 nm increased from 220 to 460 W/g (for 800 Oe). These exchange-coupled Fe3O4/CoFe2O4 core/shell nanoparticles can be a good candidate for advanced hyperthermia application.

Fe3O4 and metal-organic framework MIL-101(Fe) composites catalyze luminol chemiluminescence for sensitively sensing hydrogen peroxide and glucose.

Science.gov (United States)

Qian Tang, Xue; Dan Zhang, Yi; Wei Jiang, Zhong; Mei Wang, Dong; Zhi Huang, Cheng; Fang Li, Yuan

2018-03-01

In this work, Fe 3 O 4 and metal-organic framework MIL-101(Fe) composites (Fe 3 O 4 /MIL-101(Fe)) was demonstrated to possess excellent catalytic property to directly catalyze luminol chemiluminescence without extra oxidants. We utilized Fe 3 O 4 /MIL-101(Fe) to develop a ultra-sensitive quantitative analytical method for H 2 O 2 and glucose. The possible mechanism of the chemiluminescence reaction had been investigated. Under optimal conditions, the relative chemiluminescence intensity was linearly proportional to the logarithm of H 2 O 2 concentration in the range of 5-150nM with a limit of detection of 3.7nM (signal-to-noise ratio = 3), and glucose could be linearly detected in the range from 5 to 100nM and the detection limit was 4.9nM (signal-to-noise ratio = 3). Furthermore, the present approach was successfully applied to quantitative determination of H 2 O 2 in medical disinfectant and glucose in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Facile fabrication of composited Mn_3O_4/Fe_3O_4 nanoflowers with high electrochemical performance as anode material for lithium ion batteries

International Nuclear Information System (INIS)

Zhao, Dianyun; Hao, Qin; Xu, Caixia

2015-01-01

Graphical abstract: Mn_3O_4/Fe_3O_4 nanoflowers are successfully prepared through one step dealloying of Mn_5Fe_5Al_9_0 alloy at room temperature. This hierarchical flower-like structure with consists of a packed array of uniform regular hexagon-like nanoslices. Combined with the specific hierarchical flower-like architecture and the synergistic effect exerted by Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits enhanced performance as anode material for lithium ion batteries than pure Mn_3O_4 and Fe_3O_4 anode. - Highlights: • Mn_3O_4/Fe_3O_4 nanoflowers are easily prepared by one step dealloying method. • The nanoflowers consist of packed regular nanoslices with interconnected voids. • Mn_3O_4/Fe_3O_4 nanoflowers deliver higher discharge capacity than Mn_3O_4 and Fe_3O_4. • Mn_3O_4/Fe_3O_4 nanoflowers show lower initial irreversible loss than Mn_3O_4 anode. - Abstract: Mn_3O_4/Fe_3O_4 nanoflowers with controllable components are simply fabricated through one step etching of the Mn_5Fe_5Al_9_0 ternary alloy. The as-made hierarchical flower-like structure with interconnected voids consists of a packed array of uniform regular hexagon-like nanoslices. Based on the simple dealloying strategy the target metals are directly converted to uniform nanocomposite composed of Mn_3O_4 and Fe_3O_4 species. With the unique hierarchical flower-like structure and the synergistic effects between Mn_3O_4 and Fe_3O_4, the nanocomposite exhibits higher performance as anode material for lithium ion batteries than that of pure Mn_3O_4 and Fe_3O_4 anodes. The Mn_3O_4/Fe_3O_4 nanocomposite deliver much higher discharge capacity and lower initial irreversible loss than Mn_3O_4 anode. The Mn_3O_4/Fe_3O_4 anode material also shows an excellent cycling stability at the high rate of 1500 mA g"−"1 with outstanding rate capability. With the advantages of simple preparation and excellent electrochemical performance, Mn_3O_4/Fe_3O_4 nanoflowers manifest great application potential as

Study on adsorption of 99Tc on Fe, Fe2O3 and Fe3O4

International Nuclear Information System (INIS)

Liu Dejun; Fan Xianhua; Zhang Yingjie; Yao Jun; Zhou Duo; Wang Yong

2004-01-01

The absorption behavior of 99 Tc on Fe, Fe 2 O 3 and Fe 3 O 4 powders from aqueous 99 TcO 4 - solutions is studied by batch method in atmospheric conditions. After the adsorption reaches equilibrium, the valence state of 99 Tc in the aqueous solution is examined by extraction with tetraphenylarsonium chloride. The experimental results show that the adsorption ratio of 99 Tc on iron powders decreases with the increase of pH (in the range of 5-8) and of CO 3 2- concentration (in the range of 1 x 10 -8 -1 x 10 -2 mol/L). In opposite, the two factors have no significant influence on the absorption of 99 Tc on both Fe 2 O 3 and Fe 3 O 4 powders. The adsorption isotherms of 99 TcO 4 - on Fe, Fe 2 O 3 and Fe 3 O 4 powders can be well described by the Freundlich's equation. The major valence state of 99 Tc is deduced to be Tc(IV) when iron powders is used as the absorbent. In the case of Fe 2 O 3 or Fe 3 O 4 as an absorbent, the 99 Tc remains as the TcO 4 - form

Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

International Nuclear Information System (INIS)

Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

2015-01-01

Fe 3 O 4 @SiO 2 –graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe 3 O 4 @SiO 2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe 3 O 4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO 2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe 3 O 4 @SiO 2 NPs was 24 ± 0.3 nm, similar to that of Fe 3 O 4 @SiO 2 –NH 2 . Fe 3 O 4 @SiO 2 –GO composites were synthesized by linking of Fe 3 O 4 @SiO 2 –NH 2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe 3 O 4 @SiO 2 –GO composite has potential applications in the production of bioethanol

Characterisation of a tertiary mixture of {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Srinivasan, M.P.; Narasimhan, S.V. [Water and Steam Chemistry Laboratory (Chemistry Group, BARC) BARC Facilities, Kalpakkam, Tamil Nadu 603 102. (India)

1998-12-31

A method has been developed to quantify the individual components of a ternary mixture containing {alpha}-Fe{sub 2}O{sub 3}, {gamma}- Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} based on the preferential dissolution of the components at a fixed time (fixed time - depending on the strength of the chelating agent) in a dilute chemical formulation (containing a chelant and an organic acid) both in presence and absence of reductant. A ternary component diagram was constructed based on the percentage dissolution of the individual components in 2,6-Pyridine dicarboxylic acid (PDCA), Nitrilo triacetic acid (NTA) and EDTA based formulation at 60degC both in presence and absence of reductant. In these formulations, the observed behaviour that the {alpha}-Fe{sub 2}O{sub 3} dissolved very little both in presence and absence of reductant and {gamma}-Fe{sub 2}O{sub 3} dissolved very little in absence of reductant were used for resolving the ternary physical mixture composition. Physical mixtures of Fe{sub 3}O{sub 4}, {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} based on mole ratio were taken such that the total quantity of Fe present would be 1.37 mM for complete dissolution. In presence and absence of reductant, dissolution percentage of Fe observed at fixed time in these formulations, when fit into the already constructed three component phase diagram for each formulation at the same fixed duration, the experimentally resolved composition showed good agreement with that based on individual components. This method is useful to resolve different polymorphs of metal oxides having the metal ions in single and/or multiple oxidation states. (author)

Fabrication and magnetic-induced aggregation of Fe{sub 3}O{sub 4}–noble metal composites for superior SERS performances

Energy Technology Data Exchange (ETDEWEB)

Gan, Zibao; Zhao, Aiwu, E-mail: awzhao@iim.ac.cn; Zhang, Maofeng; Wang, Dapeng; Guo, Hongyan; Tao, Wenyu; Gao, Qian; Mao, Ranran; Liu, Erhu [Chinese Academy of Sciences, Institute of Intelligent Machines (China)

2013-11-15

Fe{sub 3}O{sub 4}–noble metal composites were obtained by combining Au, Ag nanoparticles (NPs) with 3-aminopropyltrimethoxysilane-functionalized Fe{sub 3}O{sub 4} NPs. UV–Visible absorption spectroscopy demonstrates the obtained Fe{sub 3}O{sub 4}–noble metal composites inherit the typical surface plasmon resonance bands of Au, Ag at 533 and 453 nm, respectively. Magnetic measurements also indicated that the superparamagnetic Fe{sub 3}O{sub 4}–noble metal composites have excellent magnetic response behavior. A magnetic-induced idea was introduced to change their aggregated states and take full advantage of their surface-enhanced Raman scattering (SERS) performances. Under the induction of an external magnetic field, the bifunctional Fe{sub 3}O{sub 4}–noble metal aggregates exhibit the unique superiority in SERS detection of Rhodamine 6G (R6G), compared with the naturally dispersed Au, Ag NPs. Especially, the detection limit of the Fe{sub 3}O{sub 4}–Ag aggregates for R6G is as low as 10{sup −14} M, and the calculated EF reaches up to 1.2 × 10{sup 6}, which meets the requirements for trace detection of analytes. Furthermore, the superiority could be extended to sensitive detection of other organic molecules, such as 4-mercaptopyridine. This work provides a new insight for active adjustment of the aggregated states of SERS substrates and the optimization of SERS performances.

Profound Interfacial Effects in CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4 Core/Shell Nanoparticles

Science.gov (United States)

Polishchuk, Dmytro; Nedelko, Natalia; Solopan, Sergii; Ślawska-Waniewska, Anna; Zamorskyi, Vladyslav; Tovstolytkin, Alexandr; Belous, Anatolii

2018-03-01

Two sets of core/shell magnetic nanoparticles, CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4, with a fixed diameter of the core ( 4.1 and 6.3 nm for the former and latter sets, respectively) and thickness of shells up to 2.5 nm were synthesized from metal chlorides in a diethylene glycol solution. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The analysis of the results of magnetic measurements shows that coating of magnetic nanoparticles with the shells results in two simultaneous effects: first, it modifies the parameters of the core-shell interface, and second, it makes the particles acquire combined features of the core and the shell. The first effect becomes especially prominent when the parameters of core and shell strongly differ from each other. The results obtained are useful for optimizing and tailoring the parameters of core/shell spinel ferrite magnetic nanoparticles for their use in various technological and biomedical applications.

Fe3O4@HKUST-1 and Pd/Fe3O4@ HKUST-1 as magnetically recyclable catalysts prepared via conversion from a Cu-based ceramic

OpenAIRE

Toyao, Takashi; Styles, Mark J.; Yago, Tokuichiro; Sadiq, Muhammad M.; Ricco, Raffaele; Suzuki, Kiyonori; Horiuchi, Yu; Takahashi, Masahide; Matsuoka, Masaya; Falcaro, Paolo

2017-01-01

Nanocomposites obtained by integrating iron oxide magnetic nanoparticles (Fe3O4) into a metal-organic framework (HKUST-1 or Cu-3(BTC)(2), BTC = 1,3,5-benzenetricarboxylate) are synthesized through conversion from a composite of a Cu-based ceramic material and Fe3O4. In situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements reveal that the presence of Fe3O4 leads to the fast conversion and synthesis of HKUST-1 with small particle sizes. The prepared MOF co...

Polarized neutron reflectivity studies of magnetic oxidic Fe3O4/NiO and Fe3O4/CoO multilayers

NARCIS (Netherlands)

Ball, A.R.; Fredrikze, H.; Lind, D.M.; Wolf, R.M.; Bloemen, P.J.H.; Rekveldt, M.Th.; Zaag, van der P.J.

1996-01-01

The magnetic properties of [1 0 0] oriented Fe3O4/NiO and Fe3O4/CoO multilayers, MBE-grown on MgO(0 0 1) substrates, have been studied by polarized neutron reflectometry. In both samples, the Fe3O4 layer exhibits a depth-dependent magnetic profile characterized by a reduction in the magnetization

Polyaniline/Fe3O4-RGO Nanocomposites for Microwave Absorption

Science.gov (United States)

Mathew, Jithin; Sathishkumar, M.; Kothurkar, Nikhil K.; Senthilkumar, R.; Sabarish Narayanan, B.

2018-02-01

Fe3O4 nanoparticles were synthesized by co-precipitation of ferric chloride (FeCl3) and ferrous chloride (FeCl2). Reduced graphene oxide (RGO) was prepared by reducing the graphene oxide, which was synthesized by Hummer’s method, using hydrazine hydrate. Three nanocomposites based on sodium dodecyl benzene sulphonate (SDBS)-doped polyaniline were synthesized through in situ polymerization in the presence of the fillers (i) Fe3O4, (ii) reduced graphene oxide (RGO) and (iii) Fe3O4-decorated RGO respectively. The synthesized PANI and the composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Their microstructures, electrical conductivities, and EMI shielding effectiveness were studied. The nanocomposite containing 10 % RGO showed the maximum electrical conductivity and the one with 10 % RGO and 10 % Fe3O4 showed the maximum EMI shielding effectiveness of 7.5 dB for a 1 mm thick sample.

Radio frequency shielding behaviour of silane treated Fe2O3/E-glass fibre reinforced epoxy hybrid composite

Science.gov (United States)

Arun prakash, V. R.; Rajadurai, A.

2016-10-01

In this work, radio frequency shielding behaviour of polymer (epoxy) matrixes composed of E-glass fibres and Fe2O3 fillers have been studied. The principal aim of this project is to prepare suitable shielding material for RFID application. When RFID unit is pasted on a metal plate without shielding material, the sensing distance is reduced, resulting in a less than useful RFID system. To improve RF shielding of epoxy, fibres and fillers were utilized. Magnetic behaviour of epoxy polymer composites was measured by hysteresis graphs (B-H) followed by radio frequency identifier setup. Fe2O3 particles of sizes 800, 200 and 100 nm and E-glass fibre woven mat of 600 g/m2 were used to make composites. Particle sizes of 800 nm and 200 nm were prepared by high-energy ball milling, whereas particles of 100 nm were prepared by sol-gel method. To enhance better dispersion of particles within the epoxy matrix, a surface modification process was carried out on fillers by an amino functional coupling agent called 3-Aminopropyltrimethoxysilane (APTMS). Crystalline and functional groups of siliconized Fe2O3 particles were characterized by XRD and FTIR spectroscopy analysis. Variable quantity of E-glass fibre (25, 35, and 45 vol%) was laid down along with 0.5 and 1.0 vol% of 800, 200, and 100 nm size Fe2O3 particles into the matrix, to fabricate the hybrid composites. Scanning electron microscopy and transmission electron microscopy images reveal the shape and size of Fe2O3 particles for different milling times and particle dispersion in the epoxy matrix. The maximum improved sensing distance of 45.2, 39.4 and 43.5 % was observed for low-, high-, and ultra-high radio frequency identifier setup along with shielding composite consist of epoxy, 1 vol% 200 nm Fe2O3 particles and 45 vol% of E-glass fibre.

Photodegradation of Methylene Blue by TiO2-Fe3O4-Bentonite Magnetic Nanocomposite

Directory of Open Access Journals (Sweden)

Wei Chen

2015-01-01

Full Text Available Fe3O4-bentonite nanoparticles have been prepared by a coprecipitation technique under a nitrogen atmosphere. An aqueous suspension of bentonite was first modified with FeCl2 and FeCl3. TiO2 was then loaded onto the surface of the Fe3O4-bentonite by a sol-gel method. After sufficient drying, the colloidal solution was placed in a muffle furnace at 773 K to obtain the TiO2-Fe3O4-bentonite composite. The material has been characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD analysis, and vibrating sample magnetometry (VSM. Morphological observation showed that Fe3O4 and TiO2 nanoparticles had been adsorbed on the surface of bentonite nanoneedles. The material was then applied for the photodegradation of the azo dye methylene blue (MB. It was found that the removal efficiency of MB exceeded 90% under UV illumination, and that only a 20% mass loss was incurred after six cycles. The composite material thus showed good photocatalytic performance and recycling properties.

Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

Science.gov (United States)

Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

2014-09-01

In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

International Nuclear Information System (INIS)

Pham, Gia Vu; Trinh, Anh Truc; Hang To, Thi Xuan; Nguyen, Thuy Duong; Nguyen, Thu Trang; Nguyen, Xuan Hoan

2014-01-01

In this study Fe 3 O 4 /CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe 3 O 4 ) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe 3 O 4 /CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe 3 O 4 /CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe 3 O 4 /CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe 3 O 4 /CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe 3 O 4 /CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe 3 O 4 /CNTs composite in the epoxy matrix. (paper)

Thermal decomposition study of Mn doped Fe3O4 nanoparticles

Science.gov (United States)

Malek, Tasmira J.; Chaki, S. H.; Tailor, J. P.; Deshpande, M. P.

2016-05-01

Fe3O4 is an excellent magnetic material among iron oxides. It has a cubic inverse spinel structure exhibiting distinguished electric and magnetic properties. In this paper the authors report the synthesis of Mn doped Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its thermal characterization. Ferric chloride hexa-hydrate (FeCl3•6H2O), manganese chloride tetra-hydrate (MnCl2•4H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the as-synthesized Mn doped Fe3O4 nanoparticles were determined by energy dispersive analysis of X-rays (EDAX) technique. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out on the Mn doped Fe3O4 nanoparticles in the temperature range of ambient to 1124 K. The thermo-curves revealed that the particles decompose by four steps. The kinetic parameters were evaluated using non-mechanistic equations for the thermal decomposition.

Photocatalytic Performance of a Novel MOF/BiFeO3 Composite

Directory of Open Access Journals (Sweden)

Yunhui Si

2017-10-01

Full Text Available In this study, MOF/BiFeO3 composite (MOF, metal-organic framework has been synthesized successfully through a one-pot hydrothermal method. The MOF/BiFeO3 composite samples, pure MOF samples and BiFeO3 samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, and by UV–vis spectrophotometry. The results and analysis reveal that MOF/BiFeO3 composite has better photocatalytic behavior for methylene blue (MB compared to pure MOF and pure BiFeO3. The enhancement of photocatalytic performance should be due to the introduction of MOF change the surface morphology of BiFeO3, which will increase the contact area with MB. This composing strategy of MOF/BiFeO3 composite may bring new insight into the designing of highly efficient photocatalysts.

Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

Science.gov (United States)

Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

2015-11-21

An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites.

Enhanced antibacterial performance of Fe3O4–Ag and MnFe2O4 ...

Indian Academy of Sciences (India)

sity in our daily life. ... enhances the biological activity of Ag NPs, but many stud- ... against Gram-positive and Gram-negative bacteria in this ..... Antimicrobial effects of Fe3O4@Nico@Ag, Fe3O4@His@Ag and Fe3O4@HA@Ag against Fe3O4 ...

Intercalating graphene with clusters of Fe3O4 nanocrystals for electrochemical supercapacitors

Science.gov (United States)

Ke, Qingqing; Tang, Chunhua; Liu, Yanqiong; Liu, Huajun; Wang, John

2014-04-01

A hierarchical nanostructure consisting of graphene sheets intercalated by clusters of Fe3O4 nanocystals is developed for high-performance supercapacitor electrode. Here we show that the negatively charged graphene oxide (GO) and positively charged Fe3O4 clusters enable a strong electrostatic interaction, generating a hierarchical 3D nanostructure, which gives rise to the intercalated composites through a rational hydrothermal process. The electrocapacitive behavior of the resultant composites is systematically investigated by cyclic voltammeter and galvanostatic charge-discharge techniques, where a positive synergistic effect between graphene and Fe3O4 clusters is identified. A maximum specific capacitance of 169 F g-1 is achieved in the Fe3O4 clusters decorated with effectively reduced graphene oxide (Fe3O4-rGO-12h), which is much higher than those of rGO (101 F g-1) and Fe3O4 (68 F g-1) at the current density of 1 Ag-1. Moreover, this intercalated hierarchical nanostructure demonstrates a good capacitance retention, retaining over 88% of the initial capacity after 1000 cycles.

Synthesis of BSA/Fe{sub 3}O{sub 4} magnetic composite microspheres for adsorption of antibiotics

Energy Technology Data Exchange (ETDEWEB)

Zhang, Baoliang; Zhang, Hepeng; Li, Xiangjie; Lei, Xingfeng; Li, Chunmei; Yin, Dezhong; Fan, Xinlong; Zhang, Qiuyu, E-mail: qyzhang@nwpu.edu.cn

2013-10-01

BSA/Fe{sub 3}O{sub 4} magnetic composite microspheres with high saturation magnetization and paramagnetic property were prepared via inverse emulsion technology at room temperature, bovine serum albumin (BSA, 60 KD), magnetic nanoparticles (Fe{sub 3}O{sub 4}) and glutaraldehyde as macromonomer, inorganic particles and cross-linking agent, respectively. Fourier transform infrared (FTIR), scanning electron microscope (SEM), metalloscope, and particle size analyzer were used to characterize morphology and structure of composite microspheres. Vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA) were used to test magnetic properties of the synthesized samples, adsorption capacity of microspheres was determined by ultraviolet spectrophotometer (UV). The results showed that BSA/Fe{sub 3}O{sub 4} microspheres were 43 μm with relatively narrow particle size distribution, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 11 emu/g, and high magnetic content with a value of 57.29%. The main factors influencing properties of microspheres including raw material ratio, the amount of emulsifier and cross-linking agent, agitation speed were investigated and optimized. Furthermore, these microspheres accompanying with high separable and reusable efficient may have great potential application in the field of separation, in particular, removal of antibiotics. Adsorption capacities of the microspheres of four different kinds of antibiotics (erythromycin, streptomycin, tetracycline and chloramphenicol) ranging from 69.35 mg/g to 147.83 mg/g were obtained, and Langmuir isotherm model coincided with equilibrium data than that of the Freundlich model. - Highlights: • BSA/Fe{sub 3}O{sub 4} microspheres with high saturation magnetization were prepared. • BSA/Fe{sub 3}O{sub 4} microspheres for the removal of antibiotics are proposed. • The obtained results have significant importance in environmental processes.

[Preparation of molecularly imprinted polypyrrole/Fe3O4 composite material and its application in recognition of tryptophan enantiomers].

Science.gov (United States)

Chen, Zhidong; Shan, Xueling; Kong, Yong

2012-04-01

Ferrosoferric oxide (Fe(3)O(4)) magnetic material was first synthesized, and then the in-situ chemical polymerization of pyrrole was carried out on the surface of Fe(3)O(4) by using pyrole and L-tryptophan (L-Trp) as the functional monomer and templates, respectively. As a result, molecularly imprinted polypyrrole/Fe(3)O(4) composite material was obtained. This composite material was separated from the solution because of its magnetic property. Polypyrrole in the composite was overoxidized in 1 mol/L NaOH solution by applying a potential of 1.0 V, and thus L-Trp templates were de-deoped from the composite. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods were employed to characterize the composite. The solution containing L- or D-Trp was pumped through a porous ceramic tube packed with the composite, separately. High performance liquid chromatography (HPLC) was adopted for the detection of L- or D-Trp in the eluate, and the results indicated that the enrichment ability of the composite for L-Trp was almost 2 times that of D-Trp. Therefore, the electro-magnetic composite material has potential applications as chromatographic stationary phase for chiral recognition.

Facile synthesis of nanorod-type graphitic carbon nitride/Fe2O3 composite with enhanced photocatalytic performance

International Nuclear Information System (INIS)

Wang, Jiangpeng; Li, Changqing; Cong, Jingkun; Liu, Ziwei; Zhang, Hanzhuo; Liang, Mei; Gao, Junkuo; Wang, Shunli; Yao, Juming

2016-01-01

Here we report a facile synthesis of nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) by using Fe-melamine supramolecular framework as precursor. The chemical and optical properties of the nanocomposites are well-characterized. The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities under visible light due to the efficient utilization of sunlight and the construction of Z-scheme electron transfer pathway. The results indicated that it could be a promising approach for the preparation of efficient g-C 3 N 4 nanocomposites photocatalysts by using metal-melamine supramolecular framework as precursors. - Graphical abstract: Nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) was synthesized by using Fe-melamine supramolecular framework as precursor. The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities under visible light. Display Omitted - Highlights: • Nanorod-type graphitic carbon nitride/Fe 2 O 3 composite (Fe 2 O 3 -g-C 3 N 4 ) was synthesized. • Fe 2 O 3 -g-C 3 N 4 showed strong optical absorption in the visible-light region. • The Fe 2 O 3 -g-C 3 N 4 nanocomposite demonstrated excellent photocatalytic activities.

Study of AC Magnetic Properties and Core Losses of Fe/Fe3O4-epoxy Resin Soft Magnetic Composite

Science.gov (United States)

Laxminarayana, T. A.; Manna, Subhendu Kumar; Fernandes, B. G.; Venkataramani, N.

Soft Magnetic Composites (SMC) were prepared by coating of nanocrystalline Fe3O4 particles, synthesized by co-precipitation method, on atomized iron powder of particle size less than 53 μm in size using epoxy resin as a binder between iron and Fe3O4. Fe3O4 was chosen, for its high electric resistivity and suitable magnetic properties, to keep the coating layer magnetic and seek improvement to the magnetic properties of SMC. SEM images and XRD patterns were recorded in order to investigate the coatings on the surface of iron powder. A toroid was prepared by cold compaction of coated iron powder at 1050 MPa and subsequently cured at 150˚C for 1 hr in argon atmosphere. For comparison of properties, a toroid of uncoated iron powder was also compacted at 1050 MPa and annealed at 600˚C for 2 hr in argon atmosphere. The coated iron powder composite has a resistivity of greater than 200 μΩm, measured by four probe method. A comparison of Magnetic Hysteresis loops and core losses using B-H Loop tracer in the frequency range 0 to 1500 Hz on the coated and uncoated iron powder is reported.

Magnetic and microstructural properties of Fe{sub 3}O{sub 4}-coated Fe powder soft magnetic composites

Energy Technology Data Exchange (ETDEWEB)

Jo Sunday, Katie [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States); Hanejko, Francis G. [Hoeganaes Corporation, Cinnaminson, NJ08077 (United States); Taheri, Mitra L., E-mail: mtaheri@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States)

2017-02-01

Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and possess high melting temperatures, thus providing adequate electrical barriers between metallic particles. In this work, iron powder was coated with Fe{sub 3}O{sub 4} particles via mechanical milling, then compacted and cured in an inert gas environment. We find density and coercivity to improve with increasing temperatures; however, core loss greatly increases, which is attributed to the formation of a more conductive iron-oxide phase and less resistive Fe volume. Our work begins to exemplify the unique qualities and potential for ferrite-based coatings using traditional powder metallurgy techniques and higher curing temperatures for electromagnetic devices. - Highlights: • Fe{sub 3}O{sub 4}-coated Fe powder was produced via mechanical milling, then compacted and cured into composite form. • SEM/EDS confirm Fe particles are individually isolated with iron-oxide coating material. • Larger particle sizes show improved core loss and coercivity measurements. • We report good magnetic properties for compaction at 800 MPa and a curing temperature of 700 °C.

Bi-functional Au/FeS (Au/Co{sub 3}O{sub 4}) composite for in situ SERS monitoring and degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Ma, Shuzhen; Cai, Qian; Lu, Kailing; Liao, Fan, E-mail: fliao@suda.edu.cn; Shao, Mingwang, E-mail: mwshao@suda.edu.cn [Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University (China)

2016-01-15

The bi-functional Au/FeS (Au/Co{sub 3}O{sub 4}) composite was fabricated by in situ reducing Au nanoparticles onto the surface of FeS (Co{sub 3}O{sub 4}). The as-prepared FeS possessed a multi-structure composed of plenty of nanoplates, which were coated by Au nanoparticles with an average size of ∼47.5 nm. While the Co{sub 3}O{sub 4} showed a thin hexagonal sheet containing Au nanoparticles on its surface with an average size of ∼79.0 nm. Both the as-prepared Au/FeS and Au/Co{sub 3}O{sub 4} composites exhibited excellent SERS performance, capable of enhancing the Raman signals of R6G molecules with the enhancement factor up to 1.81 × 10{sup 6} and 7.60 × 10{sup 4}, respectively. Moreover, Au/FeS (Au/Co{sub 3}O{sub 4}) composite also has been verified to have intrinsic peroxidase-like activity, which could decompose H{sub 2}O{sub 2} into hydroxyl radicals and then degrade organic pollutants into small molecules. Therefore, SERS can be used to real-time and in situ monitoring the degradation process of R6G molecules, employing the Au/FeS (Au/Co{sub 3}O{sub 4}) composite both as SERS substrate and catalyst. Graphical abstract: SERS was used to real-time and in situ monitoring the degradation of R6G, employing the Au/FeS and Au/Co{sub 3}O{sub 4} composites both as SERS substrates and catalysts.

Strong magnetoelectric coupling in CoFe2O4-BaTiO3 composites prepared by molten-salt synthesis method

International Nuclear Information System (INIS)

Nie Junwu; Xu Guoyue; Yang Ying; Cheng Chuanwei

2009-01-01

Magnetoelectric nano-composites (1 - x)CoFe 2 O 4 + (x)BaTiO 3 with x varies as 0, 0.5, 0.65 and 1.0 in molar ratio were prepared by molten-salt synthesis method. The structural analysis carried out by X-ray diffraction (XRD) technique has confirmed that both phases are present in all the nano-composites powders and ceramic composites. The TEM images show that the nano-particle crystallite size is about 50-80 nm, which is consistent to the result calculated by XRD. The dielectric constant was studied as a function of frequency for ceramic composites sintered by using those nano-composite powders. The saturation magnetization (Ms) and remnant polarization (Pr) were calculated from the magnetic hysteresis loop and electric hysteresis loop, respectively. And a large ME coefficient of about 17.04 mV cm -1 Oe -1 was observed for 0.5CoFe 2 O 4 + 0.5BaTiO 3 ME composite under the ac superimposed magnetic signal with 20 kHz frequency by using the lock-in technique

Synthesis, characterization, and comparative gas-sensing properties of Fe{sub 2}O{sub 3} prepared from Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}-chitosan

Energy Technology Data Exchange (ETDEWEB)

Cuong, Nguyen Duc [Faculty of Hospitality and Tourism, Hue University, 22 Lam Hoang, Vy Da Ward, Hue City (Viet Nam); College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Hoa, Tran Thai; Khieu, Dinh Quang [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Lam, Tran Dai [Institute of Materials Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Hoa, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Van Hieu, Nguyen, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2012-05-15

Highlights: Black-Right-Pointing-Pointer We have demonstrated a facile method to prepare Fe{sub 3}O{sub 4} nanoparticles and chitosan-coated Fe{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer {alpha}-Fe{sub 2}O{sub 3} sensors prepared from those Fe{sub 3}O{sub 4} materials have been investigated and compared. Black-Right-Pointing-Pointer The results show potential application of {alpha}-Fe{sub 2}O{sub 3} for CO sensors in environmental monitoring. - Abstract: In this paper, Fe{sub 3}O{sub 4} and chitosan (CS)-coated Fe{sub 3}O{sub 4} nanoparticles were synthesized via co-precipitation method and subsequent covalent binding of CS onto the surface for functionalization, respectively. Characterization of the crystal structures and morphologies of as-synthesized nanoparticles by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy demonstrated that Fe{sub 3}O{sub 4} had a cubic spinal structure with irregular shapes and average diameters of 10-20 nm. The surface states and magnetic properties of Fe{sub 3}O{sub 4}-CS nanoparticles were characterized by Fourier transform infrared spectra and vibrating sample magnetometry. Results showed that Fe{sub 3}O{sub 4}-CS nanoparticles possessed super-paramagnetic properties, with saturated magnetization up to 60 emu/g. In addition, Fe{sub 3}O{sub 4} and CS-coated Fe{sub 3}O{sub 4} nanoparticles were used in the fabrication of {alpha}-Fe{sub 2}O{sub 3} based gas sensors. Gas sensing measurements revealed that the {alpha}-Fe{sub 2}O{sub 3} gas sensor prepared from Fe{sub 3}O{sub 4}-CS had a better response to H{sub 2}, CO, C{sub 2}H{sub 5}OH, and NH{sub 3} compared with the device prepared from pristine Fe{sub 3}O{sub 4}. Furthermore, the {alpha}-Fe{sub 2}O{sub 3} sensor prepared from Fe{sub 3}O{sub 4}-CS nanoparticles exhibited the highest response to CO among the test gases, suggesting that it has great potential for practical applications in environmental monitoring.

Vapor diffusion synthesis of rugby-shaped CoFe2O4/graphene composites as absorbing materials

International Nuclear Information System (INIS)

Zhang, Shenli; Jiao, Qingze; Hu, Ju; Li, Jingjing; Zhao, Yun; Li, Hansheng; Wu, Qin

2015-01-01

Graphical abstract: CoFe 2 O 4 rugbies/graphene composites were prepared using a vapor diffusion method followed by calcination. As-synthesized rugby-like CoFe 2 O 4 particles were distributed on the graphene sheet. PVP played a key role for the formation of rugby-shaped morphology of CoFe 2 O 4 particles. A minimum reflection loss of −39.0 dB was observed at 10.9 GHz for the CoFe 2 O 4 rugbies/graphene composites with a thickness of 2 mm, and the effective absorption bandwidth was 4.7 GHz. The CoFe 2 O 4 rugbies/graphene composites exhibited better microwave absorbing performance than that of the CoFe 2 O 4 nanoparticles/graphene composites prepared without PVP. - Highlights: • CoFe 2 O 4 rugbies/graphene hybrids were synthesized using a vapor diffusion method. • PVP played a key role for the formation of CoFe 2 O 4 rugbies. • CoFe 2 O 4 rugbies/graphene composites showed excellent microwave absorbing property. - Abstract: Rugby-shaped CoFe 2 O 4 /graphene composites were synthesized using a vapor diffusion method in combination with calcination. The morphologies and structures of the products were characterized by field emission scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The magnetic and electromagnetic parameters were measured using a vibrating sample magnetometer and a vector network analyzer, respectively. Results show that rugby-shaped CoFe 2 O 4 particles are distributed on graphene sheets. A minimum reflection loss (RL) of −39.0 dB is observed at 10.9 GHz for the sample with a thickness of 2.0 mm, and the effective absorption frequency (RL < −10 dB) ranges from 9.6 to 14.3 GHz, indicating the excellent microwave absorption performance of the products. The absorbing performance of the CoFe 2 O 4 rugbies/graphene composites is better than that of the CoFe 2 O 4 nanoparticles/graphene composites

Magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes for bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Wei Yan; Zhang Xuehui; Hu Xiaoyang; Deng Xuliang [Department of Geriatric Dentistry, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Song Yu; Lin Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Han Bing [Department of Orthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Wang Xinzhi, E-mail: kqdengxuliang@bjmu.edu.cn [Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China)

2011-10-15

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe{sub 3}O{sub 4}/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe{sub 3}O{sub 4} nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe{sub 3}O{sub 4} nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe{sub 3}O{sub 4}, CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe{sub 3}O{sub 4} loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe{sub 3}O{sub 4} nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe{sub 3}O{sub 4} nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe{sub 3}O{sub 4} nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous

Effect of Fe{sub 2}O{sub 3} in Fe{sub 2}O{sub 3}/AP composite particles on thermal decomposition of AP and on burning rate of the composite propellant

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhenye [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China); Nanjing University of Technology, Nanjing (China); Li, Fengsheng; Bai, Huaping [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing, 210094 (China)

2006-12-15

A technique of composite processing of Fe{sub 2}O{sub 3} and ammonium perchlorate (AP) was employed in making the propellant. The effects of composite processing of Fe{sub 2}O{sub 3} on catalytic activity, on the thermal decomposition of AP, and on the burning rate of the composite propellant were investigated in this paper. Fe{sub 2}O{sub 3}/AP composite particles were prepared by a novel solvent-nonsolvent method. The results show that AP is successfully coated on the surface of Fe{sub 2}O{sub 3}. Composite processing of Fe{sub 2}O{sub 3} and AP can improve the catalytic activity of Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3} exhibits better catalytic effect with increasing Fe{sub 2}O{sub 3} content. The larger interface between Fe{sub 2}O{sub 3} and AP and lower density of composite propellant (with the added Fe{sub 2}O{sub 3}/AP composite particles) are responsible for the enhancement of the catalytic activity of Fe{sub 2}O{sub 3}. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Exchange bias effect in Au-Fe3O4 nanocomposites

International Nuclear Information System (INIS)

Chandra, Sayan; Frey Huls, N A; Phan, M H; Srinath, S; Srikanth, H; Garcia, M A; Lee, Youngmin; Wang, Chao; Sun, Shouheng; 2UB, Universitat de Barcelona, Avenida Diagonal 647, E-08028 Barcelona (Spain))" data-affiliation=" (Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Avenida Diagonal 647, E-08028 Barcelona (Spain))" >Iglesias, Òscar

2014-01-01

We report exchange bias (EB) effect in the Au-Fe 3 O 4 composite nanoparticle system, where one or more Fe 3 O 4 nanoparticles are attached to an Au seed particle forming ‘dimer’ and ‘cluster’ morphologies, with the clusters showing much stronger EB in comparison with the dimers. The EB effect develops due to the presence of stress at the Au-Fe 3 O 4 interface which leads to the generation of highly disordered, anisotropic surface spins in the Fe 3 O 4 particle. The EB effect is lost with the removal of the interfacial stress. Our atomistic Monte Carlo studies are in excellent agreement with the experimental results. These results show a new path towards tuning EB in nanostructures, namely controllably creating interfacial stress, and opens up the possibility of tuning the anisotropic properties of biocompatible nanoparticles via a controllable exchange coupling mechanism. (paper)

Influence of gamma-radiation on percolation threshold in PE/α-Fe2O3 composite system

International Nuclear Information System (INIS)

Aliyev, N.S.; Bayramov, M.N.

2014-01-01

Full text : In this work it has been studied the change of specific volume resistance and also percolation threshold shift of the samples exposed to initial and gamma-irradiation depending on volume share of the filler α-Fe 2 O 3 in PE/α-Fe 2 O 3 composite. On the other hand while the volume share of the filler increases, the dimensions of polymer layer decreases on the border between phases

CMC-coated Fe3O4 nanoparticles as new MRI probes for hepatocellular carcinoma

International Nuclear Information System (INIS)

Sitthichai, Sudarat; Pilapong, Chalermchai; Thongtem, Titipun; Thongtem, Somchai

2015-01-01

Highlights: • Fe 3 O 4 nanoparticles (NPs) are superparamagnetic. • CMC is water-soluble and nontoxic cellulose-derivative polymer. • CMC-coated Fe 3 O 4 NPs were successfully prepared by co-precipitation method. • The promising NPs that can be used for magnetic resonance imaging application. - Abstract: Pure Fe 3 O 4 nanoparticles and Fe 3 O 4 magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl 2 ·4H 2 O and FeCl 3 ·6H 2 O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe 3 O 4 MNPs consisting of Fe 2+ and Fe 3+ ions with 543.3-mM −1 s −1 high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

Study of cerium doped magnetite (Fe{sub 3}O{sub 4}:Ce)/PMMA nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Padalia, Diwakar, E-mail: Padalia.diwakar@gmail.com [Department of Physics, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttrakhand (India); Johri, U.C. [Department of Physics, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttrakhand (India); Zaidi, M.G.H. [Supercritical Fluid Processing Laboratory, Department of Chemistry, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttrakhand (India)

2012-03-01

The paper presents the synthesis and properties of polymer nanocomposite material based on cerium doped magnetite (Fe{sub 3}O{sub 4}) as filler material and poly methyl methacrylate (PMMA) as host matrix. The magnetite (Fe{sub 3}O{sub 4}) particles were synthesized by co-precipitation route using stable ferrous and ferric salts with ammonium hydroxide as precipitating agent. Further, they doped by cerium oxide (CeO{sub 2}) non-stoichiometrically. The composite material was fabricated by solvent evaporation method. Here 2.4 GHz microwaves were used to study the effect of microwaves heating on polymerization. The phase and crystal structure is determined by X-ray diffraction (XRD). The average crystallite size of the composites varies from 28 to 35 nm. The chemical structure is confirmed by Fourier transform infrared (FTIR) spectroscopy. The magnetic and thermal properties are investigated by vibrating sample magnetometer (VSM) and differential scanning calorimetry (DSC). The thermal study shows that the microwave heated samples possess higher glass transition temperature (T{sub g}). The magnetic results suggest that coercivity (H{sub C}) and squareness (M{sub r}/M{sub s}) of the loop increases with increasing doping percent of cerium.

NaCl leached sustainable porous flexible Fe3O4 decorated RGO-polyaniline/PVDF composite for durable application against electromagnetic pollution

Directory of Open Access Journals (Sweden)

R. Bera

2017-05-01

Full Text Available To avoid the interference of electromagnetic radiation from other devices, an electronic device needs to be fabricated with flexible and light weight electromagnetic interference (EMI shielding materials with high efficiency. According, highly flexible porous poly(vinylidene fluoride (PVDF/PFR (Fe3O4 decorated polyaniline/RGO composite composite was prepared through solution blending of PVDF with pre-synthesized PFR conductive composite that involves in-situ oxidative polymerization of aniline in the presence of reduced graphene oxide (RGO using FeCl3 as oxidant. The porous morphology of the composite was created by leaching out of mixed NaCl from the composite. Polyaniline and RGO were mutually decorated by chemically in-situ synthesized ferrosoferric oxide (Fe3O4 using the Fe source of FeCl3. A homogeneous dispersion of PFR in insulated PVDF matrix resulted in a highly electrical conductive composite (PVDF-PFR material through formation of three dimensional continuous conductive networks of polyaniline-RGO in the matrix phase. The composite shows an outstanding EMI shielding effectiveness (EMI SE property due to the porous structure and the presence of conductive network and ferromagnetic Fe3O4 nanoparticles. The PVDF-PFR composite (0.5 mm thickness depicts a great permittivity and permeability value and achieve high EMI SE value (≈–28.18 dB and conductivity value of ≈1.10·10–1 S·cm–1 at very low loading (5 wt% of RGO.

Synthesis of Fe3O4/polypyrrole/polyaniline nanocomposites by in-situ method and their electromagnetic absorbing properties

Directory of Open Access Journals (Sweden)

Bingzhen Li

2017-05-01

Full Text Available Fe3O4/PPy/PANI (Fe3O4/polypyrrole/polyaniline nanocomposites with excellent microwave absorbing properties have been successfully synthesized and characterized systematically. In detail, Fe3O4 nanoparticles were prepared via an environmental friendly, modified co-precipitation method. Afterward, two conductive polymers, PPy and PANI, were deposited onto the surface of Fe3O4 nanoparticles by in-situ polymerization of pyrrole and aniline. PPy and PANI was “glued” by the strong affinity between the carbonyl groups of PPy and the conjugated chains of PANI. The obtained Fe3O4/PPy/PANI nanocomposites have been found to possess excellent microwave absorbing property with the absorption bandwidth of 10.7 GHz (6.7–17.4 GHz and maximum reflection loss at 10.1 GHz (−40.2 dB. It proves that the combination of ultra-small Fe3O4 nanoparticles with two different conductive polymers have a great potential in the application of microwave absorbing materials.

Solvothermal synthesis and good microwave absorbing properties for magnetic porous-Fe3O4/graphene nanocomposites

Directory of Open Access Journals (Sweden)

Xiaojun Zeng

2017-05-01

Full Text Available The magnetic porous-Fe3O4/graphene nanocomposites have been fabricated by a facile solvothermal method. The porous Fe3O4 nanospheres are embedded uniformly in the graphene oxide (GO sheets to form a 3D Fe3O4/GO nanocomposite network. The dielectric properties for the Fe3O4/GO composites can be greatly improved by the 7 wt% GO additions. Good impedance matching can be also obtained in these Fe3O4/GO composites, which is proved to dominate their excellent microwave absorbing properties including the minimum reflection loss (RL value of -43.7 dB at 6.8 GHz with a sample thickness of 5 mm and a broad absorption bandwidth of 5.92 GHz (below -10 dB. These porous-Fe3O4/GO composites also exhibit the good structural stability and low density, which shows their great potential application in high-performance electromagnetic microwave-absorbing materials.

Synthesis and characterization of magnetic diphase ZnFe2O4/γ-Fe2O3 electrospun fibers

International Nuclear Information System (INIS)

Arias, M.; Pantojas, V.M.; Perales, O.; Otano, W.

2011-01-01

Magnetic nanofibers of ZnFe 2 O 4 /γ-Fe 2 O 3 composite were synthesized by electrospinning from a sol-gel solution containing a molar ratio (Fe/Zn) of 3. The effects of the calcination temperature on phase composition, particle size and magnetic properties have been investigated. Zinc ferrite fibers were obtained by calcinating the electrospun fibers in air from 300 to 800 deg. C and characterized by thermogravimetric analyses, Fourier transformed infrared spectroscopy, X-ray photoemission spectroscopy, X-ray diffraction, vibration sample magnetometry and magnetic force microscopy. The resulting fibers, with diameters ranging from 90 to 150 nm, were ferrimagnetic with high saturation magnetization as compared to bulk. An increase in the calcination temperature resulted in an increase in particle size and saturation magnetization. The observed increase in saturation magnetization was most likely due to the formation and growth of ZnFe 2 O 4 /γ-Fe 2 O 3 diphase crystals. The highest saturation magnetization (45 emu/g) was obtained for fibers calcined at 800 deg. C. - Research highlights: → Nanofibers were produced by electrospinning from a sol-gel. → ZnFe 2 O 4 /γ-Fe 2 O 3 formed after cacination in air from 300 to 800 deg. C. → Fibers were ferrimagnetic with high saturation magnetization. → Crystallite particle size and saturation magnetization increase with temperature. → Magnetic domains with sizes similar to topographical grains were observed.

Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness

International Nuclear Information System (INIS)

Gu, Shu-Ying; Jin, Sheng-Peng; Gao, Xie-Feng; Mu, Jian

2016-01-01

Polylactide-based polyurethane shape memory nanocomposites (Fe 3 O 4 /PLAUs) with fast magnetic responsiveness are presented. For the purpose of fast response and homogeneous dispersion of magnetic nanoparticles, oleic acid was used to improve the dispersibility of Fe 3 O 4 nanoparticles in a polymer matrix. A homogeneous distribution of Fe 3 O 4 nanoparticles in the polymer matrix was obtained for nanocomposites with low Fe 3 O 4 loading content. A small agglomeration was observed for nanocomposites with 6 wt% and 9 wt% loading content, leading to a small decline in the mechanical properties. PLAU and its nanocomposites have glass transition around 52 °C, which can be used as the triggering temperature. PLAU and its nanocomposites have shape fixity ratios above 99%, shape recovery ratios above 82% for the first cycle and shape recovery ratios above 91% for the second cycle. PLAU and its nanocomposites also exhibit a fast water bath or magnetic responsiveness. The magnetic recovery time decreases with an increase in the loading content of Fe 3 O 4 nanoparticles due to an improvement in heating performance for increased weight percentage of fillers. The nanocomposites have fast responses in an alternating magnetic field and have potential application in biomedical areas such as intravascular stent. (paper)

Electrostatic Self-Assembly of Fe3O4 Nanoparticles on Graphene Oxides for High Capacity Lithium-Ion Battery Anodes

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Jung Kyoo Lee

2013-09-01

Full Text Available Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g−1, high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyltrimethoxysilane (APTMS] in an acidic solution (pH = 2 followed by in situ chemical reduction. Thus prepared Fe3O4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe3O4 electrode. The superior electrochemical responses of Fe3O4/GS composite disks assure the advantages of: (1 electrostatic self-assembly between high storage-capacity materials with GO; and (2 incorporation of GS in the Fe3O4/GS composite for high capacity lithium-ion battery application.

Morphology and composition tailoring of Co x Fe3 - x O4 nanoparticles

Science.gov (United States)

Fernandes de Medeiros, I. A.; Madigou, V.; Lopes-Moriyama, A. L.; Pereira de Souza, C.; Leroux, Ch.

2018-01-01

Nano-octahedra of cobalt ferrite Co x Fe3 - x O4 (1 ≤ x hydrothermal method using nitrates as precursors. For the first time, single-phased nano-octahedra of cobalt-rich ferrite Co x Fe3 - x O4 ( x = 1.5) were synthesized. The nano-octahedra are crystallized in a normal spinel structure, with tetrahedral sites occupied by Co2+. This specific octahedral shape was obtained with anionic, cationic, and nonionic surfactants. The nature of the surfactant influenced the chemical composition of the powder and the size of the nano-octahedra. The {100} truncation of the octahedra is more pronounced for the small particles. For the first time, single-phased nanoparticles with as much as x = 1.8 cobalt were synthesized with ethylene glycol as solvent. These nanoparticles, around 8 nm in size, have no specific shape and possess a lacunar spinel structure similar to maghemite. The samples were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy.

Generalized green synthesis of Fe{sub 3}O{sub 4}/Ag composites with excellent SERS activity and their application in fungicide detection

Energy Technology Data Exchange (ETDEWEB)

Guo, Hongyan; Zhao, Aiwu, E-mail: awzhao@iim.ac.cn [University of Science and Technology of China, Department of Chemistry (China); Wang, Rujing [Chinese Academy of Sciences, Institute of Intelligent Machines (China); Wang, Dapeng [University of Science and Technology of China, Department of Chemistry (China); Wang, Liusan; Gao, Qian; Sun, Henghui [Chinese Academy of Sciences, Institute of Intelligent Machines (China); Li, Lei; He, Qinye [University of Science and Technology of China, Department of Chemistry (China)

2015-12-15

This paper reports the generalized green synthesis of a series of Fe{sub 3}O{sub 4}/Ag composites by magnetron sputtering method. The amounts of silver nanoparticles located on the hollow Fe{sub 3}O{sub 4} magnetic nanoparticles can be tuned by controlling the sputtering time. The surfaces of Fe{sub 3}O{sub 4}/Ag composites are rough with high density and numerous Ag nanogaps (which can serve as Raman active hot spots to amplify the Raman signal), providing the sound reliability and reproducibility of Raman detection. With p-aminothiophenol and Rhodamine 6G (R6G) for probe molecules, the surface-enhanced Raman scattering (SERS) properties of these Fe{sub 3}O{sub 4}/Ag composites were studied. It was found that the SERS signal reached the maximum with the sputtering time of 130 s, indicating that this compound had most hot spots. In this paper, we used the composite with the strongest SERS signal for thiram detection, and the detection limit can reach 5 × 10{sup −7} mol/L (about 0.012 ppm), which is lower than the maximal residue limit of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency. The Fe{sub 3}O{sub 4}/Ag composites are readily available, easy to carry, and show great potential for applications in universal SERS substrates in practical SERS detection.

Enhanced lithium-ion storage performance by structural phase transition from two-dimensional rhombohedral Fe_2O_3 to cubic Fe_3O_4

International Nuclear Information System (INIS)

Ren, Yurong; Wang, Jiawei; Huang, Xiaobing; Ding, Jianning

2016-01-01

Highlights: • The rhombohedral Fe_2O_3 transforms to the cubic Fe_3O_4 via a calcination treatment. • Phase structure of anodes has great influences on their electrochemical performances. • Fe_3O_4/reduced graphene oxide shows a high capacity of 825.3 mAh g"−"1 at 50 mA g"−"1. - Abstract: The electrochemical performance of a material varies with its structural phase transition. It is found that the rhombohedral Fe_2O_3 can transform to the cubic Fe_3O_4 via a calcination treatment in a nitrogen atmosphere, and lithium-ion storage performances of Fe_3O_4 get an obvious improvement due to its structural advantages. On the basis of data calculated by X-ray diffraction, the larger unit cell volume as well as the higher void fraction of cubic Fe_3O_4 provides lithium-ions with more transport channels for Li ions diffusion and storage without serious volume change, and thus the cubic Fe_3O_4 delivers an excellent reversible capacity of 921.1 mAh g"−"1 after 15 cycles at the current density of 50 mA g"−"1, which is much higher than 328.3 mAh g"−"1 for the rhombohedral Fe_2O_3. To further enhance the structural stability of electrodes, reduced graphene oxide is introduced. The Fe_3O_4/reduced graphene oxide show an excellent specific capacity of 825.3 mAh g"−"1 after 40 cycles and impressive rate performance of 600 mAh g"−"1 at the current density of 400 mA g"−"1, which are much higher than that of Fe_3O_4 (417 and 300 mAh g"−"1), Fe_2O_3 (137.4 and 95 mAh g"−"1) and Fe_2O_3/reduced graphene oxide (390.1 and 480 mAh g"−"1). These results demonstrate that the structural phase transition and reduced graphene oxide of Fe_3O_4/reduced graphene oxide composites offer unique characteristics suitable for high-performance energy storage application.

Preparation and photocatalytic activity of ZnO/Fe{sub 2}O{sub 3} nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Liu, Yanjun; Sun, Li; Wu, Jiagen; Fang, Ting; Cai, Ran; Wei, Ang, E-mail: wei1177@126.com

2015-04-15

Highlights: • ZnO/Fe{sub 2}O{sub 3} tubular structure was prepared via photochemical deposition at RT. • The composites show a great improvement in photocatalytic characteristics. • The possible reasons of photocatalytic performance of composites were researched. • The formation mechanism of ZnO/Fe{sub 2}O{sub 3} tubular structure was discussed. - Abstract: Fe{sub 2}O{sub 3} nanoparticles were grown on ZnO nanorods (NRs) to form ZnO/Fe{sub 2}O{sub 3} nanotube (NT) composites via photochemical deposition under ultraviolet light irradiation at a room temperature. Fe{sup 3+} ions in the solution preferentially adhere to the metastable Zn-rich (0 0 0 1) polar surfaces in ZnO NRs, which leading to the formation of ZnO/Fe{sub 2}O{sub 3} NTs. ZnO/Fe{sub 2}O{sub 3} NT nanocomposites show a great improvement in photocatalytic characteristics compared with the bare ZnO NRs. It can be inferred that the enhanced photocatalytic performance of ZnO/Fe{sub 2}O{sub 3} is benefit from the synergistic effect of ZnO and Fe{sub 2}O{sub 3} semiconductors.

Magnetic SiO2/Fe3O4 colloidal crystals

International Nuclear Information System (INIS)

Huang, C-K; Hou, C-H; Chen, C-C; Tsai, Y-L; Chang, L-M; Wei, H-S; Hsieh, K-H; Chan, C-H

2008-01-01

We proposed a novel technique to fabricate colloidal crystals by using monodisperse SiO 2 coated magnetic Fe 3 O 4 (SiO 2 /Fe 3 O 4 ) microspheres. The magnetic SiO 2 /Fe 3 O 4 microspheres with a diameter of 700 nm were synthesized in the basic condition with ferric sulfate, ferrous sulfate, tartaric acid and tetraethyl orthosilicate (TEOS) in the reaction system. Monodisperse SiO 2 /Fe 3 O 4 superparamagnetic microspheres have been successfully used to fabricate colloidal crystals under the existing magnetic field

Fe2O3/ZnO/ZnFe2O4 composites for the efficient photocatalytic degradation of organic dyes under visible light

Science.gov (United States)

Li, Xiaojuan; Jin, Bo; Huang, Jingwen; Zhang, Qingchun; Peng, Rufang; Chu, Shijin

2018-06-01

In this study, novel ternary Fe2O3/ZnO/ZnFe2O4 (ZFO) composites were successfully prepared through a simple hydrothermal reaction with subsequent thermal treatment. The as-prepared products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) measurement, and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic degradation of rhodamine B (Rh B) under visible light irradiation indicated that the ZFO composites calcined at 500 °C has the best photocatalytic activity (the photocatalytic degradation efficiency can reach up to 95.7% within 60 min) and can maintain a stable photocatalytic degradation efficiency for at least three cycles. In addition, the photocatalytic activity of ZFO composites toward dye decomposition follows the order cationic Rh B > anionic methyl orange. Finally, using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species during the degradation reaction of Rh B.

Facile synthesis of ZnFe{sub 2}O{sub 4}-graphene aerogels composites as high-performance anode materials for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Wang, Yu [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Jin, Yuhong, E-mail: jinyh@bjut.edu.cn [Beijing Guyue New Materials Research Institute, Beijing University of Technology, Beijing 100124 (China); Zhang, Rupeng [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

2017-08-15

Highlights: • 3D ZnFe{sub 2}O{sub 4}-graphene aerogel composites are obtained by a facile method. • The specific capacity of as-prepared 3D ZnFe{sub 2}O{sub 4}-graphene aerogel composites are 1049 mAh g{sup −1} at 100 mA g{sup −1} after 100 cycles. • Excellent rate capabilities are observed for 3D ZnFe{sub 2}O{sub 4}-graphene aerogel. • 3D ZnFe{sub 2}O{sub 4}-graphene aerogel shows enhanced cyclic stability. - Abstract: ZnFe{sub 2}O{sub 4}-graphene aerogels (ZnFe{sub 2}O{sub 4}/GAs) composites are prepared by two-step method (hydrothermal-calcination). Highly-purified ZnFe{sub 2}O{sub 4} nanoparticles are dispersed uniformly on three-dimensional (3D) GAs substrate. The mass loading of ZnFe{sub 2}O{sub 4} in ZnFe{sub 2}O{sub 4}/GAs composites is 89.3%. Compared with pure ZnFe{sub 2}O{sub 4} sample, the ZnFe{sub 2}O{sub 4}/GAs composites exhibit much higher irreversible capacity of 1449.4 mAh g{sup −1} and enhanced cycling stability (1049 mAh g{sup −1} at 100 mA g{sup −1} after 100 cycles). The improved electrochemical performance of the ZnFe{sub 2}O{sub 4}/GAs composites could be attributed from the synergetic effect between 3D conductive GAs and nanostructured ZnFe{sub 2}O{sub 4}.

Electrochemical properties of LaFeO3-rGO composite

Directory of Open Access Journals (Sweden)

Yongjie Yuan

2017-02-01

Full Text Available LaFeO3-xwt% rGO composite (x = 8, 10, 12 was synthesized by ultraphonic stirring and lyophilization method. SEM, TEM and XRD results show that the perovskite-type LaFeO3 was dispersed by rGO to form special porous structure due to the gauze-shaped wrinkles and folds structure of rGO. It was found that the special porous structure can effectively increase the specific surface area and suppress particle aggregation of LaFeO3, thus improving the electrical conductivity and appreciably enhancing the electrochemical properties of LaFeO3. As compared with LaFeO3, the maximum discharge capacity of the composite (x=10 increased from 209.5 mAh g–1 to 334.6 mAh g–1. The High rate dischargeability at a discharge current density of 1500 mA g–1 (HRD1500 and the capacity retention rate after 100 charge/discharge cycles (S100 of the composite increased by 9% and 17%, respectively.

Magnetocapacidad en nanopartículas de Fe3O4 y NiFe2O4

Directory of Open Access Journals (Sweden)

Mira, J.

2010-02-01

Full Text Available We have synthesized NiFe2O4 (φ∼ 6 nm and Fe3O4 (φ∼ 30 nm magnetic nanoparticles by solvothermal synthesis; furthermore the Fe3O4 nanoparticles have been coated with a SiO2 shell of approximately 5 nm of thickness by the Stöber method. In the study of the dielectric properties as a function of the frequency, temperature and applied magnetic field, we observe a magnetocapacitive behavior (MC at room temperature and under a moderate magnetic field (H=0.5T, that is specially important in the case of the Fe3O4, nanoparticles (MC≈ 6%. On the other hand, the NiFe2O4 and Fe3O4@SiO2 samples present smaller magnetocapacitive effects: MC≈ 2% y MC≈ 1%, respectively. These MC values, that are higher than those reported in the literature for other related magnetic nanoparticles, corroborate the theoretical model proposed by Catalán in which the combination of Maxwell-Wagner effects and magnetoresistance promote the appearance of stronger magnetocapacitive effects.Hemos preparado nanopartículas magnéticas de NiFe2O4 (φ∼ 6 nm y Fe3O4 (φ∼ 30 nm mediante el método de síntesis solvotermal; además estas últimas han sido recubiertas con una capa de SiO2 de unos 5 nm de espesor mediante el método de Stöber. Al estudiar el comportamiento dieléctrico en función de la frecuencia, temperatura y campo magnético aplicado, observamos un comportamiento magnetocapacitivo (MC a temperatura ambiente y bajo un campo magnético moderado (H= 0.5 T que es especialmente importante en el caso de las nanopartículas de Fe3O4 (MC≈ 6%. Por su parte las muestras de NiFe2O4 y Fe3O4@SiO2 presentan efectos magnetocapacitivos menores: MC≈ 2% y MC≈ 1%, respectivamente. Estos valores de MC, que son considerablemente superiores a los descritos hasta el momento para otras nanopartículas magnéticas, corroboran la predicción teórica de Catalán de que la combinación de efecto Maxwell-Wagner con efectos magnetorresitivos potencian la aparición de fen

Fabrication of graphene oxide decorated with Fe{sub 3}O{sub 4}@SiO{sub 2} for immobilization of cellulase

Energy Technology Data Exchange (ETDEWEB)

Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang, E-mail: zhangyewang@ujs.edu.cn [Jiangsu University, School of Pharmacy (China); Zhang, Xiao-Yun, E-mail: zhangxiaoyungu@126.com [Jiangsu University, School of Food and Biological Engineering (China)

2015-01-15

Fe{sub 3}O{sub 4}@SiO{sub 2}–graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe{sub 3}O{sub 4}@SiO{sub 2} and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe{sub 3}O{sub 4} nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO{sub 2} layer was calculated as being 6.5 ± 0.2 nm. The size of Fe{sub 3}O{sub 4}@SiO{sub 2} NPs was 24 ± 0.3 nm, similar to that of Fe{sub 3}O{sub 4}@SiO{sub 2}–NH{sub 2}. Fe{sub 3}O{sub 4}@SiO{sub 2}–GO composites were synthesized by linking of Fe{sub 3}O{sub 4}@SiO{sub 2}–NH{sub 2} NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe{sub 3}O{sub 4}@SiO{sub 2}–GO composite has potential applications in the production of bioethanol.

Crystal structure of LaFe5Ge3O15 = LaFe5[GeO4][Ge2O7]O4

International Nuclear Information System (INIS)

Genkina, E.A.; Maksimov, B.A.; Mill, B.V.

1991-01-01

The authors have determined the structure of a new lanthanum-iron germanate LaFe 5 [GeO 4 ][GeO 4 ][Ge 2 O 7 ]O 4 (a = 18.040(4), b = 17.012(4), c = 7.591(1) angstrom, V = 2330.2(9) angstrom 3 , Z = 8, ρ t = 4.99 g/cm 3 , space ground Cmca, 1976 I hkl ≥ 3 σ(I), R = 4.5%). The compound is interesting because the framework simultaneously contains ortho- and diorthogroups of Ge and because of a classical set of coordination numbers (4,5,6) characteristic of trivalent iron within the composition of one structure. The coordination polyhedron of La has nine vertices

Core–shell structured FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} soft magnetic composite cores with tunable insulating layer thicknesses

Energy Technology Data Exchange (ETDEWEB)

Fan, Xi’an, E-mail: groupfxa@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wang, Jian, E-mail: snove418562@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wu, Zhaoyang, E-mail: wustwuzhaoyang@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Li, Guangqiang, E-mail: ligq-wust@mail.wust.edu.cn [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China)

2015-11-15

Graphical abstract: - Highlights: • FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores were prepared. • SiO{sub 2} surrounding FeSiAl were replaced by Al{sub 2}O{sub 3} during sintering process. • Fe{sub 3}Si particles were separated by Al{sub 2}O{sub 3} with tunable thickness in composite cores. • Fe{sub 3}Si/Al{sub 2}O{sub 3} had lower core loss and better frequency stability than FeSiAl core. • The insulating layer between ferromagnetic particles can reduce core loss. - Abstract: FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses have been synthesized via a modified Stöber method combined with following high temperature sintering process. Most of the conductive FeSiAl particles could be coated by insulating SiO{sub 2} using the modified Stöber method. During the sintering process, the reaction 4Al + 3SiO{sub 2} ≣ 2α-Al{sub 2}O{sub 3} + 3Si took place and the new Fe{sub 3}Si/Al{sub 2}O{sub 3} composite was formed. The Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores displayed more excellent soft magnetic properties, better frequency stability at high frequencies, much higher resistivity and lower core loss than the raw FeSiAl core. Based on this, several types of FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses were selectively prepared by simply varying TEOS contents. The thickness of Al{sub 2}O{sub 3} insulating layer and resistivity of Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores increased with increasing the TEOS contents, while the permeability and core loss changed in the opposite direction.

Synthesis and adsorption properties of hierarchical Fe{sub 3}O{sub 4}@MgAl-LDH magnetic microspheres

Energy Technology Data Exchange (ETDEWEB)

Wu, Xiaoge; Li, Bo; Wen, Xiaogang, E-mail: wenxg@scu.edu.cn [Sichuan University, School of Materials Science and Engineering (China)

2017-04-15

In this study, Fe{sub 3}O{sub 4} microspheres were prepared by a hydrothermal method, and then the synthesized Fe{sub 3}O{sub 4} microspheres were used as template to prepare Fe{sub 3}O{sub 4}@MgAl-LDH composite microspheres by a coprecipitation process. Morphology, composition, and crystal structure of synthesized nanomaterials were characterized by X-ray powder diffractometry, scanning electron microscopy, and Fourier transform infrared spectroscopy technologies. The composite hierarchical microspheres are composed of inner Fe{sub 3}O{sub 4} core and outer MgAl-LDH-nanoflake layer, and the average thickness of MgAl-LDH-nanoflake is about 70 nm. The adsorption property of the products toward congo red was also measured using UV–vis spectrometer. The result demonstrated that the Fe{sub 3}O{sub 4}@MgAl-LDH composite adsorbent could remove 99.8% congo red in 30 min, and the maximum adsorption capacity is about 404.6 mg/g, while congo red removal rate of pure MgAl-LDH and Fe{sub 3}O{sub 4} are only 86.3 and 53.1% in 40 min, respectively, and their adsorption capacity are 345.72 and 220.56 mg/g, respectively. It indicates the composite Fe{sub 3}O{sub 4}@ MgAl-LDH nanomaterials have better adsorption performance than pure Fe{sub 3}O{sub 4} and MgAl-LDH nanomaterials. In addition, the magnetic nanocomposites could be separated easily, and it demonstrated good cycle performance.

P(VDF-TrFE)/ZrO{sub 2} polymer-composites for X-ray shielding

Energy Technology Data Exchange (ETDEWEB)

Fontainha, Crissia Carem Paiva [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Baptista Neto, Annibal Theotonio; Santos, Adelina Pinheiro; Faria, Luiz Oliveira de, E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2016-03-15

Poly(vinylidene fluoride - tryfluorethylene) [P(VDF-TrFE)] copolymers were mixed with zirconia nanoparticles. The investigation was conducted with the intention to produce nanocompounds with potential to be used as protective patient shielding in radiological procedures. Polymer based nanocomposites with 1, 2, 3, 5 and 10 wt% of ZrO{sub 2} nanoparticles were prepared using sol-gel route with zirconium butoxide as the precursor for zirconium oxide nanoclusters. UV-Vis and FTIR spectrometry and differential scanning calorimetry (DSC) were used to characterize the composite samples. We observed a more homogeneous distribution of ZrO{sub 2} nanoparticles encapsulated by methyl methacrylate (MMA) into the polymeric matrix, when compared to composites made without the use of surface modifiers from methacrylate group. Apparently, this property is related to the absence of the strong MMA absorption band at 1745 cm{sup -1}, attributed to C=O bond, in the P(VDF-TrFE)/ZrO{sub 2} -MMA nanocomposites. The radiation damage due to high dose exposure was performed for gamma doses ranging from 100 kGy to 1,000 kGy. The radiation shielding characterization conducted using x-rays with effective energy of 40 keV has demonstrated that composites with 10% of ZrO{sub 2}, and only 1.0 mm thick, can attenuate 60% of the x-rays beam. (author)

Synthesis and characterization of magnetic opal/Fe3O4 colloidal crystal

Science.gov (United States)

Carmona-Carmona, A. J.; Palomino-Ovando, M. A.; Hernández-Cristobal, Orlando; Sánchez-Mora, E.; Toledo-Solano, M.

2017-03-01

We report an experimental study of colloidal crystals based on SiO2 artificial opals, infiltrated with 1.34(M1), 2.03(M2) and 24.4(M3) wt% Fe3O4 nanoparticles, using the co-assembly method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and Vibration sample magnetometer (VSM) were used to study the structural, magnetic and optical properties of the samples. At 300 K all the samples exhibit superparamagnetic behavior due to the magnetic coupling of Fe3O4 nanoparticles infiltrated into opal. However, for higher concentration of nanoparticles this strong coupling distorts the opal network. The UV-vis diffuse reflectance spectroscopy and Kubelka-Munk theory were applied to determine that the energy band gap of the opal-magnetite composites can be adjusted by varying the concentration of Fe3O4 nanoparticles. This values are between the energy band gap of SiO2 and Fe3O4.

The Magnetoelectric Effect of a Ni0.3Zn0.62Cu0.08Fe2O4 - PbFe0.5Nb0.5O3 Multilayer Composite

Directory of Open Access Journals (Sweden)

Guzdek P.

2014-10-01

Full Text Available The magnetoelectric effect in multiferroic materials has been widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, and Pb(Fe0.5Nb0.5O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetoelectric effect of a multilayer (laminated structure consisting of 6 nickel ferrite and 7 PFN relaxor layers. It describes the synthesis and tape casting process for Ni0.3Zn0.62Cu0.08Fe2O4 ferrite and relaxor PbFe0.5Nb0.5O3 (PFN. Magnetic hysteresis, ZFC - FC curves and dependencies of magnetization versus temperature for PFN relaxor and magnetoelectric composite were measured with a vibrating sample magnetometer (VSM in an applied magnetic field up to 85 kOe at a temperature range of 10 – 400 K. Magnetoelectric effect at room temperature was investigated as a function of a static magnetic field (0.3 - 6.5 kOe and the frequency of sinusoidal magnetic field (0.01 - 6.5 kHz. At lower magnetic field, the magnetoelectric coefficient increases slightly before reaching a maximum and then decreases. The magnetoelectric coefficient aME increases continuously as the frequency is raised, although this increase is less pronounced in the 1-6.5 kHz range. Maximum values of the magnetoelectric coefficient attained for the layered composites exceed about 50 mV/(Oe cm.

CoFe2O4-SiO2 Composites: Preparation and Magnetodielectric Properties

Directory of Open Access Journals (Sweden)

T. Ramesh

2016-01-01

Full Text Available Cobalt ferrite (CoFe2O4 and silica (SiO2 nanopowders have been prepared by the microwave hydrothermal (M-H method using metal nitrates as precursors of CoFe2O4 and tetraethyl orthosilicate as a precursor of SiO2. The synthesized powders were characterized by XRD and FESEM. The (100-x (CoFe2O4 + xSiO2 (where x = 0%, 10%, 20%, and 30% composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD, Fourier transformation infrared (FTIR spectra, and scanning electron microscopy (SEM, respectively. The effect of SiO2 content on the magnetic and electrical properties of CoFe2O4/SiO2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.

Incorporation of the Fe3O4 and SiO2 nanoparticles in epoxy-modified silicone resin as the coating for soft magnetic composites with enhanced performance

Science.gov (United States)

Luo, Dahao; Wu, Chen; Yan, Mi

2018-04-01

Three inorganic-organic hybrids have been designed by incorporating epoxy-modified silicone resin (ESR) with SiO2, Fe3O4 and their mixture in the application as the coating of Fe soft magnetic composites (SMCs). The introduced SiO2 nanoparticles are well dispersed in the ESR, while the Fe3O4 tends to agglomerate or even separate from the ESR. Simultaneous addition of the SiO2 and Fe3O4 gives rise to satisfactory distribution of both nanoparticles and optimized magnetic performance of the SMCs with high permeability (124.6) and low loss (807.8 mW/cm3). On one hand, introduction of the ferromagnetic Fe3O4 reduces the magnetic dilution effect, which is beneficial for improved magnetization and permeability. On the other hand, SiO2 incorporation prevents the agglomeration of the Fe3O4 nanoparticles and gives rise to increased electrical resistivity for reduced core loss as well as enhanced mechanical strength of the SMCs.

PREPARATION AND VISIBLE LIGHT RESPONSIVE PHOTOCATALYTIC ACTIVITY OF Fe3O4/Ni-Al-Ce LDH/Bi2WO6 COMPOSITES

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Jiaqi Hao

Full Text Available Novel Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites were prepared through a hydrothermal method and co-precipitation method. The morphologies and structures of the photocatalysts were characterized by XRD, Raman, TEM, UV-vis-DRS, BET surface area and VSM techniques. The photocatalytic performances of the photocatalysts were investigated by the decolorization of methyl orange (MO under visible-light irradiation. The results showed that the Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites exhibited greater photocatalytic activities compared to pure Bi2WO6 and the Ni-Al-Ce LDH; the decolorization rate of MO was 87% within 60 min under visible-light irradiation. The decolorization efficiency of the composite material remained at 71% after 4 recycling runs, showing improved stability. Furthermore, the experimental results also showed that the photocatalytic reactions for the composites followed first-order reaction kinetics. Therefore, the Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites were photocatalysts with high efficiencies and stabilities for a photocatalytic reaction of an organic pollutant, and this study provides a new, effective method for the development of wastewater treatment.

Preparation, characterization, and antibacterial activity of NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2} nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Allafchian, Alireza, E-mail: Allafchian@cc.iut.ac.ir [Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156–83111 (Iran, Islamic Republic of); Jalali, Seyed Amir Hossein [Institute of Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan 84156–83111 (Iran, Islamic Republic of); Department of Natural Resources, Isfahan University of Technology, Isfahan 84156–83111 (Iran, Islamic Republic of); Bahramian, Hamid; Ahmadvand, Hossein [Department of physics, Isfahan University of Technology, Isfahan 84156–83111 (Iran, Islamic Republic of)

2016-04-15

We have described a facile fabrication of silver deposited on the TiO{sub 2}, Poly Acrylonitrile Co Maleic Anhydride (PAMA) polymer and nickel ferrite composite (NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2}) through a three-step procedure. A pre-synthesized NiFe{sub 2}O{sub 4} was first coated with PAMA polymer and then Ag–TiO{sub 2} was deposited on the surface of PAMA polymer shell. After the characterization of this three-component composite by various techniques, such as FTIR, XRD, FESEM, BET, TEM and VSM, it was impregnated in standard antibiotic discs. The antibacterial activity of NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2} nanocomposite was investigated against some gram positive and gram negative bacteria by employing disc diffusion assay and then compared with that of naked NiFe{sub 2}O{sub 4}, NiFe{sub 2}O{sub 4}/Ag, AgNPs and NiFe{sub 2}O{sub 4}/PAMA. The results demonstrated that the AgNPs, when embedded in TiO{sub 2} and combined with NiFe{sub 2}O{sub 4}/PAMA, became an excellent antibacterial agent. The NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2} nanocomposite could be readily separated from water solution after the disinfection process by applying an external magnetic field. - Highlights: • A novel NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2} magnetic nanocomposite has been prepared. • This nanocomposite displays potent antimicrobial activity. • The antibacterial effect was evaluated by the disk diffusion method. • Recyclable antibacterial activity of NiFe{sub 2}O{sub 4}/PAMA/Ag–TiO{sub 2} was studied.

Photocatalytic degradation of RhB over MgFe2O4/TiO2 composite materials

International Nuclear Information System (INIS)

Zhang Lei; He, Yiming; Wu Ying; Wu Tinghua

2011-01-01

Highlights: → Novel composite MgFe 2 O 4 /TiO 2 as catalyst. → Higher activity for the photodegradation of RhB under visible light irradiation. → Calcination temperature of catalyst has effect on photocatalytic activity. → Different photocatalysis mechanism under UV and visible light irradiation. - Abstract: MgFe 2 O 4 /TiO 2 (MFO/TiO 2 ) composite photocatalysts were successfully synthesized using a mixing-annealing method. The synthesized composites exhibited significantly higher photocatalytic activity than a naked semiconductor in the photodegradation of Rhodamine B. Under UV and visible light irradiation, the optimal percentages of doped MgFe 2 O 4 (MFO) were 2 wt.% and 3 wt.%, respectively. The effects of calcination temperature on photocatalytic activity were also investigated. The origin of the high level of activity was discussed based on the results of X-ray diffraction, UV-vis diffuse reflection spectroscopy, scanning electron microscopy, transmission electron microscopy, and nitrogen physical adsorption. The enhanced activity of the catalysts was mainly attributed to the synergetic effect between the two semiconductors, the band potential of which matched suitably.

Novel ZnO/MgO/Fe2O3 composite optomagnetic nanoparticles

International Nuclear Information System (INIS)

Kamińska, I; Sikora, B; Fronc, K; Dziawa, P; Sobczak, K; Minikayev, R; Paszkowicz, W; Elbaum, D

2013-01-01

A facile sol–gel synthesis of novel ZnO/MgO/Fe 2 O 3 nanoparticles (NPs) is reported and their performance is compared to that of ZnO/MgO. Powder x-ray diffraction (XRD) patterns reveal the crystal structure of the prepared samples. The average particle size of the sample was found to be 4.8 nm. The optical properties were determined by UV–vis absorption and fluorescence measurements. The NPs are stable in biologically relevant solutions (phosphate buffered saline (PBS), 20 mM, pH = 7.0) contrary to ZnO/MgO NPs which degrade in the presence of inorganic phosphate. Superparamagnetic properties were determined with a superconducting quantum interference device (SQUID). Biocompatible and stable in PBS ZnO/MgO/Fe 2 O 3 core/shell composite nanocrystals show luminescent and magnetic properties confined to a single NP at room temperature (19–24 ° C), which may render the material to be potentially useful for biomedical applications. (paper)

Electrophoretically-Deposited Nano-Fe3O4@carbon 3D Structure on Carbon Fiber as High-Performance Supercapacitors

Science.gov (United States)

Hajalilou, Abdollah; Etemadifar, Reza; Abbasi-Chianeh, Vahid; Abouzari-Lotf, Ebrahim

2018-05-01

Structural and electrochemical behaviors of electrophortically-deposited Fe3O4 and Fe3O4@C nanoparticles on carbon fiber (CF) were investigated. The nanoparticles were synthesized via a green-assisted hydrothermal route. The as-prepared samples were characterized by x-ray diffraction, transmission and scanning electron microscopies, Fourier transform infrared and UV-visible spectroscopies as well as by a vibration sample magnetometer. Surprisingly, the saturation magnetization (M s) of the Fe3O4@C ( 26.99 emu/g) was about 20% higher than that of Fe3O4 nanoparticles. A rather rectangular CV curve for both the elecrophortically-deposited Fe3O4 and Fe3O4@C on CF indicated the double-layer supercapacitor behavior of the samples. The synergistic effects of double shells improved the electrochemical behavior of Fe3O4@CF. The Fe3O4@C@CF composite exhibited a higher specific capacitance of 412 F g-1 at scan rate of 0.05 V/s compared to the Fe3O4@CF with a value of 193 F g-1. The superb electrochemical properties of Fe3O4@C@CF confirm their potential for applications as supercapacitors in the energy storage field.

Vapor diffusion synthesis of rugby-shaped CoFe{sub 2}O{sub 4}/graphene composites as absorbing materials

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shenli [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Jiao, Qingze [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); School of Chemical Engineering and Materials Science, Beijing Institute of Technology, Zhuhai, Zhuhai 519085 (China); Hu, Ju; Li, Jingjing [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Zhao, Yun, E-mail: zhaoyun@bit.edu.cn [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Li, Hansheng; Wu, Qin [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China)

2015-05-05

Graphical abstract: CoFe{sub 2}O{sub 4} rugbies/graphene composites were prepared using a vapor diffusion method followed by calcination. As-synthesized rugby-like CoFe{sub 2}O{sub 4} particles were distributed on the graphene sheet. PVP played a key role for the formation of rugby-shaped morphology of CoFe{sub 2}O{sub 4} particles. A minimum reflection loss of −39.0 dB was observed at 10.9 GHz for the CoFe{sub 2}O{sub 4} rugbies/graphene composites with a thickness of 2 mm, and the effective absorption bandwidth was 4.7 GHz. The CoFe{sub 2}O{sub 4} rugbies/graphene composites exhibited better microwave absorbing performance than that of the CoFe{sub 2}O{sub 4} nanoparticles/graphene composites prepared without PVP. - Highlights: • CoFe{sub 2}O{sub 4} rugbies/graphene hybrids were synthesized using a vapor diffusion method. • PVP played a key role for the formation of CoFe{sub 2}O{sub 4} rugbies. • CoFe{sub 2}O{sub 4} rugbies/graphene composites showed excellent microwave absorbing property. - Abstract: Rugby-shaped CoFe{sub 2}O{sub 4}/graphene composites were synthesized using a vapor diffusion method in combination with calcination. The morphologies and structures of the products were characterized by field emission scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The magnetic and electromagnetic parameters were measured using a vibrating sample magnetometer and a vector network analyzer, respectively. Results show that rugby-shaped CoFe{sub 2}O{sub 4} particles are distributed on graphene sheets. A minimum reflection loss (RL) of −39.0 dB is observed at 10.9 GHz for the sample with a thickness of 2.0 mm, and the effective absorption frequency (RL < −10 dB) ranges from 9.6 to 14.3 GHz, indicating the excellent microwave absorption performance of the products. The absorbing performance of the CoFe{sub 2}O{sub 4} rugbies/graphene composites is better than that of the CoFe

Electrochemical performance of carbon-encapsulated Fe3O4 nanoparticles in lithium-ion batteries: morphology and particle size effects

International Nuclear Information System (INIS)

Zhang, Yongguang; Li, Yue; Li, Haipeng; Zhao, Yan; Yin, Fuxing; Bakenov, Zhumabay

2016-01-01

Graphical abstract: Cycling performance and schematic of the fabrication process for the Fe 3 O 4 @C composites. - Highlights: • Carbon-encapsulated Fe 3 O 4 nanoparticles with varied microstructures were produced. • Pomegranate-like Fe 3 O 4 @C electrodes exhibit enhanced cycling ability and rate ability. • The carbon content has impact on the specific capacity of the Fe 3 O 4 @C electrodes. - Abstract: Carbon-encapsulated Fe 3 O 4 nanoparticles (Fe 3 O 4 @C) with varied microstructures were produced by controlling the relative concentrations of glucose and iron nitrate hydrate in a hydrothermal process, followed by heat treatment in Ar atmosphere. Three Fe 3 O 4 @C nanocomposites with different particle sizes (mean diameter 31.2, 45.1 and 55.3 nm) and Fe 3 O 4 core size (26.8, 15.4 and 10.3 nm) were investigated for lithium storage performance. The Fe 3 O 4 @C nanoparticles with 15.4 nm Fe 3 O 4 core exhibit excellent initial specific capacity (1215 mAh g −1 ) and significantly improved cycling performance (806 mAh g −1 after 100 cycles) and rate capability (573 mAh g −1 at current density of 1500 mA g −1 ), in comparison to the other Fe 3 O 4 @C composites. This superior performance is attributed to microstructural effects spawned from the pomegranate-like carbon coating architecture of the composite, the appropriate carbon content, and the optimized particle size of Fe 3 O 4 @C nanoparticles, which combined suppress the agglomeration and pulverization of Fe 3 O 4 nanoparticle upon cycling and enhance the electrical conductivity of the Fe 3 O 4 anode.

A new route for the synthesis of graphene oxide–Fe3O4 (GO–Fe3O4) nanocomposites and their Schottky diode applications

International Nuclear Information System (INIS)

Metin, Önder; Aydoğan, Şakir; Meral, Kadem

2014-01-01

Highlights: • Graphene Oxide (GO)–Fe 3 O 4 nanocomposites were prepared by a novel and facile method. • The successful assembly of Fe 3 O 4 NPs onto GO sheets was displayed by TEM. • The GO–Fe 3 O 4 nanocomposites/p-Si junction showed good rectifying property. -- Abstract: Addressed herein is a facile method for the preparation of magnetic graphene oxide–Fe 3 O 4 (GO–Fe 3 O 4 ) nanocomposites and the rectifying properties of (GO–Fe 3 O 4 )/p-Si junction in a Schottky diode. GO–Fe 3 O 4 nanocomposites were prepared by a novel method in which as-prepared GO sheets were decorated with the monodisperse Fe 3 O 4 nanoparticles (NPs) in dimethylformamide/chloroform mixture via a sonication process. The successful assembly of Fe 3 O 4 NPs onto GO sheets was displayed by transmission electron microscopy (TEM). Inductively couple plasma optical emission spectroscopy (ICP-OES) analysis of the GO–Fe 3 O 4 nanocomposite showed that the nanocomposite consists of 20.1 wt% Fe 3 O 4 NPs which provides a specific saturation magnetization (Ms) as 16 emu/g. The current–voltage (I–V) characteristics of the (GO–Fe 3 O 4 )/p-Si junction in a Schottky diode were studied in the temperature range of 50–350 K in the steps of 25 K. It was determined that the barrier height and ideality factor of the Au/GO–Fe 3 O 4 /p-Si/Al Schottky diode were depended on temperature as the barrier height increased while the ideality factor decreased with increasing temperature. The experimental values of barrier height and ideality factor were varied from 0.12 eV and 11.24 at 50 K to 0.76 eV and 2.49 at 350 K, respectively. The Richardson plot exhibited non-linearity at low temperatures that was attributed to the barrier inhomogeneities prevailing at the GO–Fe 3 O 4 /p-Si junction

Synthesis of ZnFe2O4/SiO2 composites derived from a diatomite template.

Science.gov (United States)

Liu, Zhaoting; Fan, Tongxiang; Zhou, Han; Zhang, Di; Gong, Xiaolu; Guo, Qixin; Ogawa, Hiroshi

2007-03-01

A novel porous ZnFe2O4/SiO2 composite product has been generated with a template-directed assembly method from porous diatomite under different synthesis conditions, such as precursor concentrations (metallic nitrates), calcination temperature and diatomite type. The phase composition and morphology of all the materials were examined by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results indicated that an inherited hierarchical porous structure from the diatomite template can be obtained, and the synthesis conditions were found to have clear effects on the formation of the ZnFe2O4/SiO2 composite. The ideal composite of ZnFe2O4/SiO2 can be obtained through optimization of diatomite template type, precursor solution and calcination temperature. Furthermore, the adsorption abilities of two types of diatomites were analyzed in detail using FTIR spectra and nitrogen adsorption measurements etc, which proved that A-diatomite (Shengzhou-diatomite) is better than B-diatomite (Changbai-diatomite) on the aspect of adsorbing Zn and Fe ions, and of forming the ZnFe2O4.

Core-Shell Nano structure of a-Fe2O3/Fe3O4: Synthesis and Photo catalysis for Methyl Orange

International Nuclear Information System (INIS)

Tian, Y.; Wu, D.; Yu, B.; Jia, X.; Zhan, S.

2011-01-01

Fe 3 O 4 nanoparticle was synthesized in the solution involving water and ethanol. Then, a-Fe 2 O 3 shell was produced in situ on the surface of the Fe 3 O 4 nanoparticle by surface oxidation in molten salts, forming α-Fe 2 O 3 /Fe 3 O 4 core-shell nano structure. It was showed that the magnetic properties transformed from ferromagnetism to superparamagnetism after the primary Fe 3 O 4 nanoparticles were oxidized. Furthermore, the obtained a-Fe 2 O 3 /Fe 3 O 4 core-shell nanoparticles were used to photo catalyse solution of methyl orange, and the results revealed that a-Fe 2 O 3 /Fe 3 O 4 nanoparticles were more efficient than the self-prepared α-Fe 2 O 3 nanoparticles. At the same time, the photo catalyzer was recyclable by applying an appropriate magnetic field.

Carbon-covered Fe_3O_4 hollow cubic hierarchical porous composite as the anode material for lithium-ion batteries

International Nuclear Information System (INIS)

Chen, Shouhui; Zhou, Rihui; Chen, Yaqin; Fu, Yuanyuan; Li, Ping; Song, Yonghai; Wang, Li

2017-01-01

In this work, Prussian blue nanocrystals, a kind of cubic metal-organic frameworks, was firstly covered by a uniform layer of resorcinol-formaldehyde (RF) resin, and then followed with heat treatment at different pyrolysis temperatures. The effects of pyrolysis temperature on the morphologies, phase, pore size, and electrochemical performance of the pyrolysis products were studied in this work. The composite generated at 600 "∘C, FexC600, was a hollow cubic composite of Fe_3O_4 covered by a thin RF-derived carbon layer. The carbon layer on FexC600 was a robust and conductive protective layer, which can accommodate Fe_3O_4 NPs and withstand the huge volume change of Fe_3O_4 during the process of discharge and charge. When used as anodes for lithium-ion batteries, FexC600 showed excellent electrochemical performance. It delivered a discharge capacity of 1126 mAh g"−"1 with a coulombic efficiency of 98.8% at the current density of 100 mA g"−"1 after 100 times discharge/charge cycling. It even delivered a capacity of 492 mAh g"−"1 at the current density of 500 mA g"−"1. This cubic hollow composite would be a promising alternative anode material for lithium-ion batteries.

Nano-sized Fe2O3/Fe3O4 facilitate anaerobic transformation of hexavalent chromium in soil-water systems.

Science.gov (United States)

Zhang, Yaxian; Li, Hua; Gong, Libo; Dong, Guowen; Shen, Liang; Wang, Yuanpeng; Li, Qingbiao

2017-07-01

The purpose of this study is to investigate the effects of nano-sized or submicro Fe 2 O 3 /Fe 3 O 4 on the bioreduction of hexavalent chromium (Cr(VI)) and to evaluate the effects of nano-sized Fe 2 O 3 /Fe 3 O 4 on the microbial communities from the anaerobic flooding soil. The results indicated that the net decreases upon Cr(VI) concentration from biotic soil samples amended with nano-sized Fe 2 O 3 (317.1±2.1mg/L) and Fe 3 O 4 (324.0±22.2mg/L) within 21days, which were approximately 2-fold of Cr(VI) concentration released from blank control assays (117.1±5.6mg/L). Furthermore, the results of denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing indicated a greater variety of microbes within the microbial community in amendments with nano-sized Fe 2 O 3 /Fe 3 O 4 than the control assays. Especially, Proteobacteria occupied a predominant status on the phylum level within the indigenous microbial communities from chromium-contaminated soils. Besides, some partial decrease of soluble Cr(VI) in abiotic nano-sized Fe 2 O 3 /Fe 3 O 4 amendments was responsible for the adsorption of nano-sized Fe 2 O 3 /Fe 3 O 4 to soluble Cr(VI). Hence, the presence of nano-sized Fe 2 O 3 /Fe 3 O 4 could largely facilitate the mobilization and biotransformation of Cr(VI) from flooding soils by adsorption and bio-mediated processes. Copyright © 2017. Published by Elsevier B.V.

Electromagnetic interference shielding and microwave absorption properties of cobalt ferrite CoFe2O4/polyaniline composite

Science.gov (United States)

Ismail, Mukhils M.; Rafeeq, Sewench N.; Sulaiman, Jameel M. A.; Mandal, Avinandan

2018-05-01

Improvement of microwave-absorbing materials (MAMs) is the most important research area in various applications, such as in communication, radiation medical exposure, electronic warfare, air defense, and different civilian applications. Conducting polymer, polyaniline doped with para toluene sulphonic acid (PANI-PTSA) as well as cobalt ferrite (CoFe2O4) is synthesized by sol-gel method and intensely blends in different ratios. The characterization of the composite materials, CoFe2O4/PANI-PTSA (CFP1, CFP2, CFP3 and CFP4), was performed by X-ray diffraction (XRD), atomic force microscopy (AFM) and vibrating sample magnetometry (VSM). The microwave-absorbing properties' reflection loss (dB) and important parameters, such as complex relative permittivity ( ɛ r '- jɛ r ″) and complex relative permeability ( µ r '- jµ r ″) were measured in different microwave frequencies in the X-band (8.2-12.4 GHz) region. The composite material CFP3 showed a wider absorption frequency range and maximum reflection loss of - 28.4 dB (99.8% power absorption) at 8.1 GHz and - 9.6 dB (> 90% power absorption) at 11.2 GHz, and so the composite can be used as a microwave absorber; however, it can be more suitable for application in daily life for making cell phones above 9 GHz. Also the results showed that the thicker composites like CFP3 (4 mm) exhibit obviously better EMI SE as compared with the thinner ones (0.19, 0.19, 0.3 mm); this may be related to the low transmission of the EM wave from the composites.

Recent advances in the synthesis of Fe3O4@AU core/shell nanoparticles

International Nuclear Information System (INIS)

Salihov, Sergei V.; Ivanenkov, Yan A.; Krechetov, Sergei P.; Veselov, Mark S.; Sviridenkova, Natalia V.; Savchenko, Alexander G.; Klyachko, Natalya L.; Golovin, Yury I.; Chufarova, Nina V.; Beloglazkina, Elena K.; Majouga, Alexander G.

2015-01-01

Fe 3 O 4 @Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of “glue” material between the core and the shell. - Highlights: • Fe 3 O 4 nanoparticles are promising for biomedical applications but have some disadvantages. • Covering Fe 3 O 4 nanoparticles with Au shell leads to better stability and biocompatibility. • Core/shell nanoparticles are widely used for biomedical applications. • There are two types of Fe 3 O 4 @Au core/shell nanoparticles structures: bi-layer and multilayer composite. • Different synthetic methods enable production of nanoparticles of different sizes

Preparation of Fe 3O 4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride) by emulsifier-free emulsion polymerization and its interaction with DNA

Science.gov (United States)

Li, Xiaolong; Liu, Guoqiang; Yan, Wei; Chu, Paul K.; Yeung, Kelvin W. K.; Wu, Shuilin; Yi, Changfeng; Xu, Zushun

2012-04-01

Cationic magnetic polymer particles Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride), a type of potential gene carrier, were prepared by emulsifier-free emulsion polymerization with oleic acid modified magnetite Fe3O4, styrene, butyl acrylate and [2-(methacryloxy)ethyl]trimethylammonium chloride) (METAC). The morphology of the particles was characterized by transmission electron microscopy and the composites of particles were characterized by FT-IR spectroscopy, X-ray diffraction. These results showed that magnetic particles were well dispersed in polymers with the content of about 15%(wt/wt). The composites exhibited superparamagnetism and possessed a certain level of magnetic response. The interactions between the particles with calf-thymus DNA (ct DNA) were confirmed by zeta potential measurement, UV-vis spectroscopy and fluorescence spectroscopy. The DNA-binding capacity determined by the agarose gel electrophoresis showed good binding capacity of the emulsion to DNA. These results suggested the potential of the cationic magnetic polymer emulsion as gene target delivery carrier.

CMC-coated Fe{sub 3}O{sub 4} nanoparticles as new MRI probes for hepatocellular carcinoma

Energy Technology Data Exchange (ETDEWEB)

Sitthichai, Sudarat [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Pilapong, Chalermchai, E-mail: chalermchai.pilapong@cmu.ac.th [Center of Excellence for Molecular Imaging (CEMI), Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai, E-mail: schthongtem@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2015-11-30

Highlights: • Fe{sub 3}O{sub 4} nanoparticles (NPs) are superparamagnetic. • CMC is water-soluble and nontoxic cellulose-derivative polymer. • CMC-coated Fe{sub 3}O{sub 4} NPs were successfully prepared by co-precipitation method. • The promising NPs that can be used for magnetic resonance imaging application. - Abstract: Pure Fe{sub 3}O{sub 4} nanoparticles and Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl{sub 2}·4H{sub 2}O and FeCl{sub 3}·6H{sub 2}O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe{sub 3}O{sub 4} MNPs consisting of Fe{sup 2+} and Fe{sup 3+} ions with 543.3-mM{sup −1} s{sup −1} high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: Prospective matrix for satellite cell adhesion and cultivation

International Nuclear Information System (INIS)

Amna, Touseef; Hassan, M. Shamshi; Van Ba, Hoa; Khil, Myung-Seob; Lee, Hak-Kyo; Hwang, I.H.

2013-01-01

We report the fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe 3 O 4 /TiO 2 hybrid nanofibers were prepared by facile sol–gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe 3 O 4 /TiO 2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe 3 O 4 /TiO 2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe 3 O 4 /TiO 2 composite nanofibers after being cultured. We observed that Fe 3 O 4 –TiO 2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe 3 O 4 /TiO 2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine. Highlights: ► We report fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers by facile electrospinning. ► The utilized satellite cells were isolated from native Korean Hanwoo cattle. ► Fe 3 O 4 /TiO 2 composite with small diameters (∼ 200 nm) can mimic the natural ECM well. ► Fe 3 O 4 /TiO 2

High Performance Lithium-Ion Hybrid Capacitors Employing Fe3O4-Graphene Composite Anode and Activated Carbon Cathode.

Science.gov (United States)

Zhang, Shijia; Li, Chen; Zhang, Xiong; Sun, Xianzhong; Wang, Kai; Ma, Yanwei

2017-05-24

Lithium-ion capacitors (LICs) are considered as promising energy storage devices to realize excellent electrochemical performance, with high energy-power output. In this work, we employed a simple method to synthesize a composite electrode material consisting of Fe 3 O 4 nanocrystallites mechanically anchored among the layers of three-dimensional arrays of graphene (Fe 3 O 4 -G), which exhibits several advantages compared with other traditional electrode materials, such as high Li storage capacity (820 mAh g -1 at 0.1 A g -1 ), high electrical conductivity, and improved electrochemical stability. Furthermore, on the basis of the appropriated charge balance between cathode and anode, we successfully fabricated Fe 3 O 4 -G//activated carbon (AC) soft-packaging LICs with a high energy density of 120.0 Wh kg -1 , an outstanding power density of 45.4 kW kg -1 (achieved at 60.5 Wh kg -1 ), and an excellent capacity retention of up to 94.1% after 1000 cycles and 81.4% after 10 000 cycles. The energy density of the Fe 3 O 4 -G//AC hybrid device is comparable with Ni-metal hydride batteries, and its capacitive power capability and cycle life is on par with supercapacitors (SCs). Therefore, this lithium-ion hybrid capacitor is expected to bridge the gap between Li-ion battery and SCs and gain bright prospects in next-generation energy storage fields.

Synergistic operation of photocatalytic degradation and Fenton process by magnetic Fe3O4 loaded TiO2

Science.gov (United States)

Sun, Qiong; Hong, Yong; Liu, Qiuhong; Dong, Lifeng

2018-02-01

The magnetic Fe3O4 loaded anatase TiO2 photocatalysts with different mass ratios were successfully synthesized by a one-step convenient calcining method. The morphology and structure analysis revealed that Fe3O4 was formed in TiO2 with very fine-grained particles. After a small amount of Fe3O4 loaded onto TiO2, the photocatalytic property enhanced obviously for the degradation of organic dye. Furthermore, the photo-Fenton-like catalysis of the iron-containing samples could also be induced after the addition of hydrogen peroxide. The apparent kinetic constant of the reaction that catalyzed by Fe-TiO2 was about 5.3 and 8.3 times of that catalyzed by TiO2 or Fe3O4 only, respectively, proving an effective synergistic contribution of the photocatalysis and Fenton reaction in the composite. Compared with Fe3O4 or free Fe3+ ions, only 13% of iron in TiO2 dissolved into acidic solution (25% for Fe3O4 and 100% for Fe3+) after the reaction, which confirmed the iron had been well immobilized onto TiO2. In addition, the extremely stable photocatalytic activity in cycling experiments proved the immobilized iron had been tightly attached onto TiO2, indicating the great potential of the catalyst for practical applications.

Fabricate BC/Fe3O4@PPy 3D nanofiber film as flexible electrode for supercapacitor application

Science.gov (United States)

Lv, Xvdan; Li, Guohui; Pang, Zengyuan; Li, Dawei; Lei, Luo; Lv, Pengfei; Mushtaq, Muhammad; Wei, Qufu

2018-05-01

For flexible film supercapacitor, high areal capacitance is a main evaluating indicator. In this paper, bacterial cellulose (BC) with special three-dimensional structure was used as the natural flexible base material. Fe3O4 nanoparticles with average diameter of 20 nm were synthesized on the surface of BC fibers. The conductive path polypyrrole (PPy) was introduced as shell of BC/Fe3O4 fibers to further improve the pseudo capacitance in 1 mol/L H2SO4 solution. Besides, the BC/Fe3O4@PPy was used for supercapacitor application in acid electrolyte, and delivered higher areal capacitance compared to other Fe3O4 composites in previous reports. The obtained BC/Fe3O4@PPy film showed excellent mechanical strength (tensile strength reached 11 MPa), high areal specific capacitance (5.4 F cm-2 at active mass of 8.4 mg cm-2), and long cycle life (1.95 F cm-2 over 3500 cycles).

Fe_3O_4/carbon nanocomposite: Investigation of capacitive & magnetic properties for supercapacitor applications

International Nuclear Information System (INIS)

Sinan, Neriman; Unur, Ece

2016-01-01

Fe_3O_4 nanoparticles with ∼10 nm diameters were synthesized by an extremely low-cost, scalable and relatively biocompatible chemical co-precipitation method. Magnetic measurements revealed that Fe_3O_4 nanoparticles have bifunctional superparamagnetic and ferromagnetic character with saturation magnetization (M_s) values of 64 and 71 emu g"−"1 at 298 K and 10 K, respectively. Pseudocapacitive Fe_3O_4 nanoparticles were then integrated into hazelnut shells - an abundant agricultural biomass - by an energy efficient hydrothermal carbonization method. Presence of magnesium oxide (MgO) ceramic template or its precursor in the hydrothermal reactor allowed simultaneous introduction of pores into the composite structure. Hierarchically micro-mesoporous Fe_3O_4/C nanocomposite possesses a high specific surface area of 344 m"2 g"−"1. Electrochemical properties of Fe_3O_4/C nanocomposite were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in a conventional three-electrode cell. The Fe_3O_4/C nanocomposite is able to operate in a large negative potential window in 1 M Na_2SO_4 aqueous electrolyte (−1.2–0 V vs. Ag/AgCl). Synergistic effect of the Fe_3O_4 and carbon leads to enhanced specific capacitance, rate capability and cyclability making Fe_3O_4/C nanocomposite a very promising negative electrode material for asymmetric supercapacitors. - Highlights: • Fe_3O_4 (magnetite) particles with ∼10 nm dia. were prepared by a facile chemical co-precipitation. • Fe_3O_4 nanospheres are superparamagnetic at 298K with high saturation magnetization of 64 emu g"−"1. • Porous Fe_3O_4/C nanocomposite was also prepared by a green HTC method combined with MgO templating. • Electrochemical properties of Fe_3O_4/C were studied in 1 M Na_2SO_4 (between −1.2 and 0 V vs. Ag/AgCl). • Nanocomposite electrode showed high energy density of 27.2 Wh kg"−"1 at 1 A g"−"1.

Enhanced photocatalytic property of BiFeO_3/N-doped graphene composites and mechanism insight

International Nuclear Information System (INIS)

Li, Pai; Li, Lei; Xu, Maji; Chen, Qiang; He, Yunbin

2017-01-01

Highlights: • A hydrothermal process was used to prepare BiFeO_3/N-doped graphene composites. • BiFeO_3/N-doped graphene exhibits superior photocatalytic activity and stability. • The energy band of BiFeO_3 bends downward by ∼1.0 eV at the composite interface. • Downward band bending leads to rapid electron transfer at the composite interface. • Holes and ·OH are predominant active species in the photo-degradation process. - Abstract: A series of BiFeO_3/(N-doped) graphene composites are prepared by a facile hydrothermal method. BiFeO_3/N-doped graphene shows photocatalytic performance superior to that of BiFeO_3/graphene and pristine BiFeO_3. The enhanced photo-degradation performance of BiFeO_3/N-doped graphene are mainly attributable to the improved light absorbance of the composite, abundant active adsorption sites and high electrical charge mobility of N-doped graphene, and the downward band bending of BiFeO_3 at the composite interface. In particular, X-ray photoelectron spectroscopy analyses reveal that the electron energy band of BiFeO_3 is downward bent by 1.0 eV at the interface of BiFeO_3/N-doped graphene, because of different work functions of both materials. This downward band bending facilitates the transfer of photogenerated electrons from BiFeO_3 to N-doped graphene and prompts the separation of photo-generated electron-hole pairs, leading eventually to the enhanced photocatalytic performance.

Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

Science.gov (United States)

Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.

2016-12-01

Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.

Orientation dependence of magnetoelectric coefficient in 1-3-type BaTiO3/CoFe2O4

Science.gov (United States)

Jian, Gang; Shao, Hui; Zhang, Cheng; Yan, Chao; Zhao, Ning; Song, Bo; Wong, C. P.

2018-03-01

Orientation dependence of magnetoelectric coefficient αE33 in 1-3-type BaTiO3/CoFe2O4 composites was calculated in arbitrary directions by three-dimensional coordinate transformation method. The space distributions of pc11‧, pc12‧, e31‧ for piezoelectric phase and mc11‧, mc12‧, q31‧ for magnetic phase were obtained independently using relative experimental data and original matrices for 4mm BaTiO3 and m3m CoFe2O4. Elastic stiffness coefficients show little orientation differences, while e31‧ and q31‧ exhibit high dependence on crystal orientation, with the MAX absolute e31‧ = 2.96 C/m2 and the MAX q31‧ = 556 × 10-12 m/A are found at θ = 0° and θ = 0°, ϕ = 45°, respectively. For space distribution of αE33‧, BaTiO3||[0 0 1]/CoFe2O4||[0 0 1] combination has the maximum value which applies to both 1-3 p/m (1.485 V/A) and 1-3 m/p composites (1.529 V/A). Volume fraction is quite independent of orientations of both piezoelectric and magnetic phases and the volume fraction for magnetic phase f around 0.5 obtains the largest αE33. The results suggest an approach to significantly enhancing magnetoelectric coefficient of composite multiferroic materials through crystal orientation controls of single crystals and textured ceramics.

Enhanced magnetization in morphologically and magnetically distinct BiFeO3 and La0.7Sr0.3MnO3 composites

Science.gov (United States)

Pillai, Shreeja; Reshi, Hilal Ahmad; Bagwaiya, Toshi; Banerjee, Alok; Shelke, Vilas

2017-09-01

Nanomaterials exhibit properties different from those of their bulk counterparts. The modified magnetic characteristics of manganite nanoparticles were exploited to improve magnetization in multiferroic BiFeO3 compound. We studied the composite of two morphologically and magnetically distinct compounds BiFeO3 (BFO) and La0.7Sr0.3MnO3 (LSMO). The microcrystalline BiFeO3 sample was prepared by solid state reaction method and the nanocrystalline La0.7Sr0.3MnO3 by sol-gel method. Composites with nominal compositions (1-x)BiFeO3-(x)La0.7Sr0.3MnO3 were prepared by modified solid state reaction method. The phase purity and crystal structures were checked by using X-ray diffraction. The formation of composites with phase separated BFO and LSMO was confirmed using Raman and Fourier Transform Infrared spectroscopy studies. The composite samples showed relatively high value of magnetization with finite coercivity. This improvement in magnetic behavior is ascribed to the coexistence of multiple magnetic orderings in composite samples. We scrutinized the possibility of oxygen vacancy or Fe mixed valency formation in the samples using X-ray photoelectron spectroscopy technique.

Magnetic contribution of Bi{sub 0.85}La{sub 0.15}FeO{sub 3} in (1−x)Bi{sub 0.85}La{sub 0.15}FeO{sub 3}–(x)CoFe{sub 2}O{sub 4} nanocomposite powders

Energy Technology Data Exchange (ETDEWEB)

Han, Ru-shuai; Qi, Li-qian; Hou, Xue; Liu, Li-hu; Liu, Hui-yuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang, Hebei 050024 (China); Xian, Xiao-Ning [Department of Information technology, Yuncheng Agricultural College, Shanxi 044000 (China); Guo, Ge-Xin [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang, Hebei 050024 (China); Sun, Hui-yuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang, Hebei 050024 (China)

2016-12-15

In this work, a solid phase reaction method was used to fabricate (1−x)Bi{sub 0.85}La{sub 0.15}FeO{sub 3}–xCoFe{sub 2}O{sub 4} (x=0.1, 0.2, 0.3, 0.4) composite powders. X-ray diffraction patterns showed that no chemical reaction occurred between the separate Bi{sub 0.85}La{sub 0.15}FeO{sub 3} and CoFe{sub 2}O{sub 4} phases and indicated that the powder samples had two distinct phases with a CoFe{sub 2}O{sub 4} spinel phase and a Bi{sub 0.85}La{sub 0.15}FeO{sub 3} perovskite phase. The average crystallite sizes of the Bi{sub 0.85}La{sub 0.15}FeO{sub 3} in the composite powder were almost unchanged as the CoFe{sub 2}O{sub 4} content was increased. By comparing the experimental and theoretical values for the magnetization, we found that the Bi{sub 0.85}La{sub 0.15}FeO{sub 3} phase contributed to the magnetization of the composite powders. In addition, it also provides a new way to prove the existence of magnetoelectric coupling in the sample. - Highlights: • Theoretical magnetic value of the samples was calculated. • The experimental value of the magnetism was greater than the theoretical value. • The effect of the crystallite sizes on the magnetism was eliminated by calculating the crystallite sizes of BLFO. • The BLFO contributed to the magnetic moment through the magnetoelectric coupling.

A note on structural and dielectric properties of BiFeO3- PbTiO3 and BiFeO3- PbZrO3 composites

International Nuclear Information System (INIS)

Satpathy, S. K.; Mohanty, N. K.; Behera, A. K.; Behera, B.; Nayak, P.

2015-01-01

The composites of BiFeO 3 -PbTiO 3 (BF-PT) and BiFeO 3 -PbZrO 3 (BF-PZ) were prepared by mixed oxide method. Room temperature X-ray diffraction data confirms the rhombohedral and tetragonal crystal structure respectively. Dielectric constant of BF-PZ is found to give high value compared to BF-PT and hence, there is an increase value of ac conductivity for the former. Both the composites show negative temperature coefficient of resistance (NTCR) behavior. The activation energies of BF-PT and BF-PZ are found to be 0.35 eV and 0.53 eV respectively. The d 33 coefficients are found to be 2.0 and 2.1 pC/N for BF-PT and BF-PZ respectively

Effect of Fe2O3 and Binder on the Electrochemical Properties of Fe2O3/AB (Acetylene Black) Composite Electrodes

Science.gov (United States)

Anh, Trinh Tuan; Thuan, Vu Manh; Thang, Doan Ha; Hang, Bui Thi

2017-06-01

In an effort to find the best anode material for Fe/air batteries, a Fe2O3/AB (Acetylene Black) composite was prepared by dry-type ball milling using Fe2O3 nanoparticles and AB as the active and additive materials, respectively. The effects of various binders and Fe2O3 content on the electrochemical properties of Fe2O3/AB electrodes in alkaline solution were investigated. It was found that the content of Fe2O3 strongly affected the electrochemical behavior of Fe2O3/AB electrodes; with Fe2O3 nanopowder content reaching 70 wt.% for the electrode and showing improvement of the cyclability. When the electrode binder polytetrafluoroethylene (PTFE) was used, clear redox peaks were observed via cyclic voltammetry (CV), while polyvinylidene fluoride-containing electrodes provided CV curves with unobservable redox peaks. Increasing either binder content in the electrode showed a negative effect in terms of the cyclability of the Fe2O3/AB electrode.