共查询到20条相似文献,搜索用时 31 毫秒
1.
Guixia Liu Xia Li Xiangting Dong Jinxian Wang 《Journal of nanoparticle research》2011,13(9):4025-4034
Solid and hollow YF3:Eu3+ spheres assembled by nanorods have been successfully synthesized via a facile arginine-assisted hydrothermal method and followed
by a subsequent heat-treatment process. The experimental results reveal that the as-prepared YF3:Eu3+ spheres are composed of the nanorods with a diameter of 20–50 nm and a length of 200–500 nm, the morphologies of YF3:Eu3+ have been changed from solid to hollow spheres assembled by nanorods. With increase of hydrothermal temperature and time,
the diameter of YF3:Eu3+ spheres can be controlled from 300 to 800 nm. The solid and hollow spheres show an intense orange red emission peak near
595 nm, corresponding to the 5D0 → 7F1 transition of Eu3+. The possible formation mechanism for the hollow spheres has been presented in detail. This amine acid-assisted method is
very simple, economic and environmental friendly for organic-free solvent, which would be potentially used in synthesizing
other hollow materials. 相似文献
2.
In this paper, a facile synthesis process is proposed to prepare multiwalled carbon nanotubes/magnetite (MWCNTs/Fe3O4) hybrids. The process involves two steps: (1) water-soluble CNTs are synthesized by one-pot modification using potassium persulfate (KPS) as oxidant. (2) Fe3O4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-CO) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe3O4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by X-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe3O4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe3O4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe3O4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe3O4 hybrids was discussed. 相似文献
3.
Run-Ping Jia Chun-fa Ou-Yang Yong-Sheng Li Jun-He Yang Wang Xia 《Journal of nanoparticle research》2008,10(1):215-219
For the first time, a newly luminescent nanomaterial, monoclinic wolframite-type HgWO4 nanorods (diameter: ∼200 nm; length: ~2000 nm) are prepared by hydrothermal method together with ultrasonic technique. Fluorescent
(FL) and UV–Vis results both show that for HgWO4, ultrasonic irradiation procedure will change its optical behaviors greatly. When the crystals become into nanorods, the
fluorescent emitting peaks (365 and 495 nm) shift to central region, and finally form a wider one at 435 nm. Similar results
of UV–visible absorption peaks are observed for these two products. FTIR spectra further characterize their structure. All
above unique optical performances might result from both small sizes caused by ultrasonic irradiation procedure and involvement
of incompact d10 electrons. Moreover, possible synthesis mechanisms of HgWO4 nanorods are also investigated. 相似文献
4.
《Current Applied Physics》2015,15(11):1534-1538
This paper reports the facile synthesis of In2O3-capped Zn-doped Fe2O3 nanorods along with their ethanol gas sensing properties. A two-stage process involving thermal oxidation of Fe foils and Zn powders in air and the sputter-deposition of In2O3 was used to synthesize these nanostructures. The nanorods synthesized using this method were ∼5 μm in length and 50–120 nm in diameter with a shell layer thickness of 10–15 nm. The multiple-networked In2O3-capped Zn-doped Fe2O3 nanorod sensor showed a significantly enhanced and ultrafast response to ethanol gas. The enhanced sensing performance was explained by modulation of the potential barrier height and the strong catalytic activity of In2O3 for ethanol oxidation. 相似文献
5.
Hao-Jie Song Xiang-Qian Shen Hai-Yan Ji Xiao-Jing Jing 《Applied Physics A: Materials Science & Processing》2010,99(3):685-689
A simple and economical route based on a K2CO3 mediated process was developed to synthesize three-dimensional (3D) flower-like Fe3O4 micro/nanoflakes on the surface of iron plates by a direct in-situ hydrothermal synthesis method. The prepared micro/nanoflakes
were characterized by X-ray diffraction and scanning electron microscopy. It was found that the width of the nanoflakes ranges
from 50 to 100 nm, and the length of the flakes is about 3 μm. The morphology of Fe3O4 nanostructures can be tuned from simple isolated nanoflakes to the ordered 3D flower-like shape by increasing the reaction
temperature. The wettability of the surface with 3D flower-like micro/nanoflakes was changed from hydrophilicity to superhydrophobicity
by chemical modification with vinyl tirethoxy-silane. The static contact angles for water on both of the modified surfaces
were larger than 150°, which was closely related to the chemical modification and hierarchical structure. Furthermore, the
surfaces retained good superhydrophobic stability in long-term storage as well, which should be critical to the application
of iron materials in engineering. 相似文献
6.
Ch.V. Subba Reddy Edwin H. Walker Jr. S.A. Wicker Sr. Quinton L. Williams Rajamohan R. Kalluru 《Current Applied Physics》2009,9(6):1195-1198
Vanadium dioxide nanorods were synthesized through a hydrothermal reaction from V2O5 xerogel, poly(vinyl pyrrolidone) (PVP) and lithium perchlorate (LiClO4). The prepared samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical discharge–charge cycling in lithium battery. SEM images reveal the nanorods to have dimensions on the order of 1–3 μm in length and 10–50 nm in diameter. The measured initial discharge capacity of the lithium battery with a cathode made of VO2 (B) nanorods was 152 mA h/g. 相似文献
7.
Uğur Tamer İsmail H. Boyacı Erhan Temur Adem Zengin İlker Dincer Yalçın Elerman 《Journal of nanoparticle research》2011,13(8):3167-3176
The preparation and application of rod-shaped core–shell structured Fe3O4–Au nanoparticles for immunomagnetic separation and sensing were described for the first time with this study. To synthesize
magnetic gold nanorod particles, the seed-mediated synthetic method was carried out and the resulting nanoparticles were characterized
with transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV–Vis), energy-dispersive X-ray (EDX), and
X-ray diffraction (XRD). Magnetic properties of the nanoparticles were also examined. Characterization of the magnetic gold
nanorod particles has proven that the resulting nanoparticles were composed of Fe3O4 core and the gold shell. The rod-shaped gold-coated iron nanoparticles have an average diameter of 16 ± 2 nm and an average
length of about 50 ± 5 nm (corresponding aspect ratio of 3). The saturation magnetization value for the magnetic gold nanorod
particles was found to be 37 emu/g at 300 K. Rapid and room temperature reaction synthesis of magnetic gold nanorod particles
and subsequent surface modification with E. coli antibodies provide immunomagnetic separation and SERS application. The analytical performance of the SERS-based homogenous
sandwich immunoassay system with respect to linear range, detection limit, and response time is also presented. 相似文献
8.
Bhupendra Singh Chia-Ling Ho Yuan-Chieh Tseng Chieh-Tsung Lo 《Journal of nanoparticle research》2012,14(2):706
Nickel phosphide (Ni2P) and bimetallic iron–nickel phosphides [(Fe
x
Ni
y
)2P] nanorods were fabricated by a seeded growth strategy. This strategy utilized pre-synthesized Fe3O4 nanoparticles as seeds and the thermal decomposition of metal precursors by multiple injections in a solution containing
trioctylphosphine and didodecyldimethylammonium bromide (DDAB). The nanorods were characterized by transmission electron microscopy,
X-ray diffraction, and magnetic measurements were carried out using superconducting quantum interference device (SQUID). The
rod length was tunable, ranging from 10 to 110 nm depending on the number of injections, whereas the diameter of the rods
was nearly 6 nm. It was found that the rod size increased with the number of injections under the constant total injection
concentration and reaction time. In addition, the effect of the DDAB quantity used as a co-surfactant was studied, which showed
that an optimum quantity was required to achieve uniform nanorods. Magnetic characterizations were performed over the two
kinds of nanorods to identify their respective magnetic phases. The results demonstrated that the Ni2P nanorods were defined as a Curie–Weiss paramagnet, whereas the (Fe
x
Ni
y
)2P nanorods exhibited superparamagnetic characteristics. 相似文献
9.
Carbon-coated Fe3O4 and pure Fe3O4 nanorods are synthesized via hydrothermal reaction and subsequent sintering procedure. The as-prepared products characterized by X-ray diffraction and scanning electron microscopy analysis indicate that carbon coating does not affect the structure and morphology of Fe3O4. Transmission electron microscope shows that Fe3O4 nanorods are homogeneously coated by carbon layer with a thickness of approximately 2 nm. The electrochemical properties measured by cyclic voltammetry, galvanostatic charge–discharge cycling and electrochemical impedance spectroscopy tests show that carbon-coated Fe3O4 (Fe3O4/C) nanorods present improved electrochemical performance due to the carbon layer. A specific capacitance of 275.9 F?g?1 is achieved at a current density of 0.5 A g?1 in 1 M Na2SO3 aqueous solution for the Fe3O4/C nanorods in comparison to that of 208.6 F?g?1 for pure Fe3O4. 相似文献
10.
Nidhi Andhariya Bhupendra Chudasama R. V. Mehta R. V. Upadhyay 《Journal of nanoparticle research》2011,13(4):1677-1688
The use of nanoparticles as drug delivery systems for anticancer therapeutics has great potential to revolutionize the future
of cancer therapy. The aim of this study is to construct a novel drug delivery platform comprising a magnetic core and biodegradable
thermoresponsive shell of tri-block-copolymer. Oleic acid-coated Fe3O4 nanoparticles and hydrophilic anticancer drug “doxorubicin” are encapsulated with PEO–PLGA–PEO (polyethylene oxide–poly d, l lactide-co-glycolide–polyethylene oxide) tri-block-copolymer. Structural, magnetic, and physical properties of Fe3O4 core are determined by X-ray diffraction, vibrating sample magnetometer, and transmission electron microscopy techniques,
respectively. The hydrodynamic size of composite nanoparticles is determined by dynamic light scattering and is found to be
~36.4 nm at 25 °C. The functionalization of magnetic core with various polymeric chain molecules and their weight proportions
are determined by Fourier transform infrared spectroscopy and thermogravimetric analysis, respectively. Encapsulation of doxorubicin
into the polymeric magnetic nanoparticles, its loading efficiency, and kinetics of drug release are investigated by UV–vis
spectroscopy. The loading efficiency of drug is 89% with a rapid release for the initial 7 h followed by the sustained release
over a period of 36 h. The release of drug is envisaged to occur in response to the physiological temperature by deswelling
of thermoresponsive PEO–PLGA–PEO block-copolymer. This study demonstrates that temperature can be exploited successfully as
an external parameter to control the release of drug. 相似文献
11.
Xiaocong Wang Saide Tang Jing Liu Ziqiong He Lijuan An Chenxi Zhang Jingmei Hao Wei Feng 《Journal of nanoparticle research》2009,11(4):923-929
Core–shell multifunctional composite spheres consisting of Fe3O4–polyaniline (PANi) shell and polystyrene (PS) core were fabricated using core–shell-structured sulfonated PS spheres (with
uniform diameter of 250 nm) as templates. PANi was doped in situ by sulfonic acid resulting the composite spheres are well
conductive. Dissolved with solvent, PS cores were removed from the core–shell composite spheres and hollow Fe3O4–PANi spheres were obtained. Removing the PANi and PS components by calcinations produced hollow Fe3O4 spheres. The cavity size of the hollow spheres was uniformly approximate to 190 nm and the shell thickness was 30 nm. The
cavity size and the shell thickness can be synchronously controlled by varying the sulfonation time of the PS templates. The
shell thickness in size range was of 20–86 nm when the sulfonation time was changed from 1 to 4 h. These resulting spheres
could be arranged in order by self-assembly of the templates. Both the Fe3O4–PANi/PS composite spheres and the hollow Fe3O4 spheres exhibit a super-paramagnetic behavior. Scanning electron microscopy, transmission electron microscopy, Fourier transform
infrared spectroscopy, and X-ray powder scattering were used to characterize these as-prepared spheres.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Xiao-hua Jia Hao-Jie Song Chun-ying Min Xue-Qiang Zhang 《Applied Physics A: Materials Science & Processing》2012,109(2):261-265
A composite of graphene (GE) supported by rod-like Fe3O4 nanocrystals has been fabricated by a simple one-step chemical route. X-ray diffraction and transmission electron microscopy results show that the Fe3O4 nanorods with diameters in the range of 15?C20 nm and lengths of 150?C200 nm were firmly assembled on the GE nanosheet surface. Magnetic property investigation indicated that the Fe3O4/GE composites exhibit a ferromagnetic behavior and possess a saturation magnetization of 50.11?emu?g?1. Moreover, Fe3O4/GE composites showed a very high adsorption capacity of Congo red. 相似文献
13.
In this study, the synthesis of monophasic nanocrystalline zinc ferrite (ZnFe2O4) was achieved by controlling the thermal decomposition conditions of a zinc–iron tartrate precursor method. Differential
thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), Fe2+ content analysis, transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) techniques were used to investigate
the effect of heat treatment conditions on the calcined powders. The thermal decomposition of the precursor led to an intermediate
phase formation of ZnO, Fe3O4, and γ-Fe2O3. It was found that the Fe3O4 → γ-Fe2O3 oxidation reaction is the key step in producing monophasic nanosized ZnFe2O4. The monophasic nanoparticles of ZnFe2O4 can be obtained when the precursor is heat treated under a low temperature (300–400 °C) and long residence time (4 h) process
that can prompt the Fe3O4 oxidation and prevent the formation of α-Fe2O3. 相似文献
14.
Reem M. Al-Tuwirqi A.A. Al-Ghamdi Faten Al-Hazmi Fowzia Alnowaiser Attieh A. Al-Ghamdi Nadia Abdel Aal Farid El-Tantawy 《Superlattices and Microstructures》2011,50(5):437-448
A mixture of crystalline Co3O4/CoO nanorods with non-uniform dense distribution has been successfully synthesized by microwave hydrothermal technique. The synthesized nanorods have been characterized by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier transforms infrared spectroscopy (FT-IR). The results showed that the as synthesized specimens contained mixed crystalline Co3O4/CoO nanorods with an average length of around 80 nm and an average diameter of 42 nm. UV–Vis spectrum of the nanorods exhibited a strong UV emission. The band energy gap of the product was 1.79 eV which lies between the energy gap of CoO and that for Co3O4. The obtained carrier concentration is of the order 4.32 × 1027 m−3 and the dielectric constant is found to be 4.89. The electrical conductivity increases with increasing temperature and behaves as a semiconducting material with an activation energy of a bout 0.26 eV. This makes the as synthesized mixed Co3O4/CoO nanorods very useful for supercapacitor devices application. Magnetic hysteresis loops at room temperature of the as synthesized mixed oxides (Co3O4/CoO) nanorods exhibit typical soft magnetic behavior. 相似文献
15.
A simple and surfactant-free synthesis of novel heterostructures comprising of copper oxide (CuO) nanowires uniformly decorated
with cobalt oxide (Co3O4) nanoparticles was demonstrated by combining thermal growth and wet-coating method. The heterostructures were synthesized
by thermally decomposing cobalt salt (cobalt nitrate) into Co3O4 nanoparticles onto vapor–solid (VS)-grown CuO nanowires. X-ray diffraction (XRD) and high resolution transmission electron
microscopy (TEM) confirmed the presence of CuO and Co3O4 phases as well as a narrow size distribution of Co3O4 nanoparticles (average diameter ~7.0 ± 1.5 nm) on CuO nanowires (average diameter of nanowire tips ~67.9 ± 18.6 nm). Unique
interfacial lattice relationship was observed for (111) Co3O4 nanoparticles on (200) CuO nanowire surface resulting in hemispherical shape of the former. For the first time, further systematic
studies were performed to understand the influence of various parameters (cobalt salt concentration and annealing temperature,
atmosphere, and time) on the morphological evolution of Co3O4 nanoparticles on CuO nanowires. Interestingly, by varying these parameters, it was possible to grow Co3O4 in different shapes (spherical, triangular, rectangular, cubical, and hexagonal nanoparticles) and forms (shells and nanorods).
It was observed that all these parameters play a critical role in influencing the surface migration, nucleation, and growth
of Co3O4 nanoparticles on CuO nanowires and this assisted in understanding the involved growth mechanisms. Finally, UV–vis–NIR spectroscopy
and band gap energies for these heterostructures were evaluated that showed higher photocatalytic degradation efficiency for
Rhodamine B under low-power visible-light illumination. 相似文献
16.
Shihui Jiao Guangsheng Pang Hongwei Liang Yan Chen Shouhua Feng 《Journal of nanoparticle research》2007,9(4):605-610
Nanoparticles and nanorods of CuSb2O6 are prepared by hydrothermal method and its high temperature α-phase is stabilized at room temperature. The average size
of the nanoparticles is ca. 13.7 nm. The nanorods, with a width of ca. 20 nm and an aspect ratio of ca. 5, are the agglomerates
composing of smaller nanoparticles with an average size of ca. 8.3 nm. Compared with the high temperature α-phase of bulk
sample at 400 K, the lattice of nanophases elongated in ab plane and compressed along c direction. The CuSb2O6 nanoparticles exhibit predominant paramagnetic phenomenon. The difference in magnetic properties of the nanoparticles and
nanorods indicates the interfacial interaction of agglomerated nanoparticles. 相似文献
17.
HaoJie Song Jing Qian XiaoHua Jia XiaoFei Yang Hua Tang Chunying Min 《Journal of nanoparticle research》2012,14(1):698
A facile solution-chemical method has been developed to be capable of covering a multiwalled carbon nanotube (MWNTs) with
iron oxide nanorods without using any bridging species. MWNTs in this composite were decorated randomly by α-Fe2O3 nanorods with diameters in the range of 3–5 nm and lengths of 15–30 nm. The formation route to anchor α-Fe2O3 nanorods onto MWNTs was proposed as the intercalation and adsorption of iron ions onto the wall of MWNTs, followed by the
nucleation and growth of α-Fe2O3 nanorods. α-Fe2O3/MWNTs nanocomposites show specific high Brunauer–Emmett–Teller surface areas. The photocatalytic activity experiment indicated
that the prepared α-Fe2O3/MWNTs nanocomposites exhibited a higher photocatalytic activity for the photocatalytic decolorization of rhodamine B aqueous
solution under the visible-light illumination than the single phase α-Fe2O3 samples. This methodology made the synthesis of MWNTs-nanorods composites possible and may be further extended to prepare
more complicated nanocomposites based on MWNTs for technological applications. 相似文献
18.
U?ur?Tamer Yusuf?Gündo?du ?smail?Hakk??Boyac? Kadir?Pekmez 《Journal of nanoparticle research》2010,12(4):1187-1196
The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention
in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the
present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution
using the borohydride reduction of HAuCl4 under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy
(TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV–Vis), and X-ray diffraction
(XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe3O4 nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface
of Fe3O4 particles exhibits uniform Fe3O4–Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated
Fe3O4 nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic
acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes.
Immunomagnetic separation was also performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied
in a range of 52.1 and 21.9% depend on the initial bacteria counts. 相似文献
19.
Prasanta Dhak D. Dhak M. Das T. Subashchandrabose P. Pramanik 《Journal of nanoparticle research》2011,13(9):4153-4159
This study reports a facile, gram-scale synthesis of FeNbO4 nanorods via hydrothermal route, using iron nitrate [Fe(NO3)3] and niobium tartarate (Nb tartarate) in presence of potassium peroxosulfate. The formation of single phase, polycrystalline
orthorhombic structure of FeNbO4 was confirmed by the careful analysis of the X-ray diffraction (XRD) pattern. The average crystallite size, calculated using
a few XRD peaks, was found to be 12.8 nm. As indicated by transmission electron microscopy (TEM) and field emission scanning
electron microscopy, the average length and diameter of the rods were found to be only 25 × 7 nm and 47 × 14 nm, respectively.
The selected area electron diffraction and high-resolution transmission electron microscopy (HRTEM) data of the single rod
implied that FeNbO4 nanorods were polycrystalline in nature and grew up along the c-axis. HRTEM also revealed that the fringes are equidistant with a lattice separation of 0.91 Ǻ, which corresponded to the
(111) plane of the FeNbO4 crystal. Elemental composition of the nanorods was confirmed using electron dispersive X-ray spectroscopy analysis while
binding state of the surface was intervened through X-ray photoelectron spectroscopy. Mechanistic investigations suggested
that potassium peroxosulfate played a crucial role in the unidirectional growth of particles. The synthetic method is simple,
amenable to scale up and contributes a new tool box for the development of FeNbO4-based one-dimensional (1D) structures that appears to be more promising for a myriad of applications, compared to their 3D
counterparts. 相似文献
20.
Li-Hua Fan Yan-Ling Luo Ya-Shao Chen Chang-Hu Zhang Qing-Bo Wei 《Journal of nanoparticle research》2009,11(2):449-458
A magnetic core–shell-layered polymer microsphere (MPS) was successfully synthesized by a dispersion polymerization route,
where the modified Fe3O4 nanoparticles (MFN) were used as a core, while poly(maleic anhydride-co-methacrylic acid) P(MAH-co-MAA) as a shell was covered
on the surface of the Fe3O4 nanoparticles. Environmental scanning electron microscope (ESME) and transmission electron microscope (TEM) measurements
indicate that the magnetic P(MAH-co-MAA)/Fe3O4 composite microspheres assume sphericity and have a novel core–shell-layered structure. The crystal particle sizes of the
unimproved Fe3O4 and the MFN samples vary from 8 to 16 nm in diameter, and the average size is about 10.6 nm in diameter. The core–shell magnetic
composite microspheres can be adjusted by changing the stirring speed. Since multiple Fe3O4 cores were coated with a proper percentage of P(MAH-co-MAA) copolymers, and therefore lower density was acquired for the
MPS, which improved sedimentation and dispersion behavior. The saturated magnetization of pure Fe3O4 nanoparticles reaches 48.1 emu g−1 and the value for composite nanoparticles was as high as 173.5 emu g−1. The nanoparticles show strong superparamagnetic characteristics and can be expected to be used as a candidate for magnetism-controlled
drug release. 相似文献