共查询到20条相似文献,搜索用时 14 毫秒
1.
Silver nanoparticles supported on superparamagnetic iron oxide (SPION)-Tween20 nanocomposite were prepared by a combined polyol and chemical reduction routes. The morphology, composition and structure of Fe 3O 4@Tween20@Ag nanocatalyst were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analyzer, and X-ray powder diffraction. In addition the magnetic properties were evaluated with vibrating sample magnetometry. It was found that Fe 3O 4@Tween20@Ag nanocatalyst could catalyze the degradation of various organic azo dyes and could easily be recovered from the reaction medium with external magnet. Also, the magnetic catalyst can be succesfully recycled and reused for at least five successive degradation cycles of methyl orange, methylene blue and Rhodamine B, confirming a high recycling efficiency. The cost effective and recyclable Fe 3O 4@Tween20@Ag nanocatalyst provide an novel nanomaterials architecture for environmental remediation applications. 相似文献
3.
Catalysis Letters - Magnetically recyclable visible light photocatalysts for the degradation of critical organic pollutants are an urgent industrial requirement. Nonetheless, one component... 相似文献
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采用溶剂热法合成了Pt/Fe3O4@C磁响应核壳催化剂,以扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和超导量子干涉磁强计(SQUID)对催化剂的结构和磁性质进行了表征。研究发现Pt颗粒均匀地分散在碳层上,Pt/Fe3O4@C催化剂显示了良好的超顺磁性。研究了Pt/Fe3O4@C磁响应催化剂上肉桂醛(CAL)的选择性加氢反应,结果显示催化剂具有良好的C=O加氢活性,在考察的条件下,肉桂醛转化率在60%左右时,肉桂醇选择性可达96%以上。催化剂在外加磁场作用下可以高效地从液相反应体系中分离,经多次循环使用后仍具有良好的催化性能。 相似文献
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Fe 3O 4 nanoparticles-decorated reduced graphene oxide magnetic nanocomposites (Fe 3O 4/rGO NCs) were prepared by a facile one-step strategy, and further used as heterogeneous Fenton-like catalysts for catalytic wet hydrogen peroxide oxidation (CWHPO) of methylene blue (MB) at 25 °C and atmospheric pressure. The effects of variables such as the Fe 3O 4/rGO with the mass ratio of rGO, initial pH, MB concentration and H 2O 2 dosage were investigated. The Fe 3O 4/rGO NCs with rGO mass ratio of 10.0 wt % showed the highest H 2O 2-activating ability, which was six-fold than that of pure Fe 3O 4 nanoparticles (NPs). The resulting catalysts demonstrated high catalytic activity in a broad operation pH range from 5 to 9, and still retained 90.5 % catalytic activity after reuse in five cycles. Taking advantage of the combined benefits of rGO and magnetic Fe 3O 4 NPs, these Fe 3O 4/rGO NCs were confirmed as an efficient heterogeneous Fenton-like catalyst for CWHPO to treat organic pollutants. And a reasonable catalytic mechanism of Fe 3O 4/rGO NCs was proposed to interpret the degradation process. 相似文献
8.
Halloysite as an impressive natural eco-friendly nanotube with aluminosilicate structure has been investigated recently due to its unique features such as specific morphology and excellent bio-adaptability. In this research, Fe3O4 nanoparticles have been loaded on the tubular halloysite by co-precipitation method in order to synthesis magnetic halloysite (Hal-Fe3O4). To characterize this recoverable nanocatalyst, applicable analyses such as Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) analysis, field-emission scanning electron microscopy (FE-SEM) images, X-ray diffraction (XRD) pattern, Thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM) curves have been carried out. The results confirmed that Fe3O4 nanoparticles with cubic structure, and uniform distribution, were located at halloysite nanotubes (HNTs). This aluminosilicate nanocomposite with high thermal stability, crystalline structure, and stable morphology was evaluated as a heterogeneous catalyst in the symmetrical Hantzsch reaction for the first time. Easy synthesis process, green media, high performance, recoverable catalyst and reusing of the Hal-Fe3O4 as a nanocatalyst for 8 times are the main features of this protocol. 相似文献
9.
Heterocyclic compounds such as spirooxindole, with five rings containing nitrogen, have an important role in the realm of medicine. This study aims to synthesize the spirooxindole derivative compounds using Fe 3O 4/graphene oxide (GO) nanocomposite as the catalyst. The GO sample was synthesized by Hummers' method, followed by the insertion of Fe 3O 4 into the graphene oxide layers by the co-precipitation method. Both XRD and FTIR analyses reveal that GO and Fe 3O 4/GO samples have been successfully formed. SEM-EDX micrograph supported by TEM image indicates that the Fe 3O 4 nanoparticles in the composite have excellent dispersibility, attributable to the existence of the GO sheets. The evaluation of the ability of Fe 3O 4/GO as a catalyst in the synthesis of spirooxindole derivatives was carried out by the one-pot three-component method. The reaction yield shows that Fe 3O 4/GO was a suitable and reusable catalyst in this reaction. 相似文献
10.
Silicon - In this article the preparation of Fe3O4@MCM-41@NH-SO3H, a new sulfonated magnetic mesoporous nanocomposite, is reported. The introduced catalyst is structurally based on MCM-41 as the... 相似文献
11.
In this study, porous calcium silicate (CaSiO 3) scaffolds were prepared by 3D gel-printing (3DGP) method and Fe 3O 4 water-based magnetic fluids (WMFs) were prepared by phacoemulsification compound chemical coprecipitation method. Fe 3O 4 WMFs were coated on CaSiO 3 scaffolds surface to prepare Fe 3O 4/CaSiO 3 composite scaffolds. The effect of WMFs with different Fe 3O 4 concentrations on porous CaSiO 3 scaffolds was studied. The composition and morphological characteristics of porous scaffolds were analyzed by using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) analysis. The magnetic properties were tested by vibrating sample magnetometer (VSM). The stability of Fe 3O 4 WMFs coatings and the degradability of composite scaffolds were tested by immersing them in simulated body fluid (SBF). The results show that when Fe 3O 4 concentration was 5.4% (w/v), the composite scaffolds had the highest saturation magnetization of 69.6 emu/g and the best stability in dynamic SBF. It is obviously that Fe 3O 4 WMFs coatings can be used for bone tissue engineering scaffolds repairing. 相似文献
12.
Catalysis Letters - Hydrophilic 2D layered silicate supported Fe3O4 catalyst (Fe3O4/2D-LS) was prepared by an impregnation method and showed greatly improved olefin selectivity in CO hydrogenation.... 相似文献
13.
Silica coated magnetite (Fe3O4@SiO2) core-shell nanoparticles (NPs) with controlled silica shell thicknesses were prepared by a modified St?ber method using 20 nm hydrophilic Fe3O4 NPs as seeds. The core-shell NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED), and UV-Vis adsorption spectra (UV-Vis). The results imply that NPs consist of a crystalline magnetite core and an amorphous silica shell. The silica shell thickness can be controlled from 12.5 nm to 45 nm by varying the experimental parameters. The reaction time, the ratio of TEOS/Fe3O4, and the concentration of hydrophilic Fe3O4 seeds were found to be very influential in the control of silica shell thickness. These well-dispersed core-shell Fe3O4@SiO2 NPs show superparamagnetic properties at room temperature. 相似文献
14.
Catalysis Letters - A magnetic recyclable Cu/ZnFe2O4 composite material was successfully prepared with easy-to-obtain raw materials. This obtained copper composite material could be employed as... 相似文献
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Silicon - Magnetic materials grafted with acetic acid (Fe3O4@SiO2COOH MNPs) were successfully prepared from the incorporation of bromoacetic acid as a functional group on the surface of magnetite... 相似文献
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Journal of Inorganic and Organometallic Polymers and Materials - A highly efficient and sustainable ferrite supported palladium nanocatalyst (Pd(II)-Benz-Am-Fe3O4@SiO2) has been prepared and... 相似文献
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Composite nanoparticles have proved to be promising in a wide range of biotechnological applications. In this paper, we report on a facile method to synthesize novel Fe(3)O(4)/Au/Fe(3)O(4) nanoparticles (nanoflowers) that integrate hybrid components and surface types. We demonstrate that relative to conventional nanoparticles with core/shell configuration, such nanoflowers not only retain their surface plasmon property but also allow for 170% increase in the saturation magnetization and 23% increase in the conjugation efficiency due to the synergistic co-operation between the hierarchical structures. Moreover, we demonstrate that the magnetic properties of such composite nanoparticles can be tuned by controlling the size of additional petals (Fe(3)O(4) phase). These novel building blocks could open up novel and exciting vistas in nanomedicine for broad applications such as biosensing, cancer diagnostics and therapeutics, targeted delivery, and imaging. 相似文献
18.
Magnetic Fe 3O 4 nanoparticles have attached attention in bone tissue engineering because of their superior magnetism and great biocompatibility. However, some disadvantages such as the potential risk of agglomeration impair their applications. Here, we proposed a hybrid magnetic nanocomposite microgel by the integration of Fe 3O 4 nanoparticles and digital lighting processing (DLP) three-dimensional (3D) printing technology. The 3D-printed microgels could be precisely customized by printing the mixture of gelatin methacryloyl (GelMA) solution and polydopamine-coated Fe 3O 4 nanoparticles, in which polydopamine decoration improved the hydrophilicity and distribution of the incorporated Fe 3O 4. The degradable microgels could be injected through a 22-G needle while retaining their original shape after injection. Interestingly, the addition of Fe 3O 4 nanoparticles into GelMA solution displayed improved printing accuracy. Moreover, these magnetic microgels were biocompatible in vitro and in vivo. After induction within osteogenic medium, addition of nanoparticles upregulated the osteogenic gene expression of rat bone mesenchymal stem cells (BMSCs). In a word, this work provides a magnetic microplatform, which shows great potential in bone tissue engineering. 相似文献
19.
The characteristics of a magnetically stabilized bed (MSB) were studied by cold‐model experiments, using water as liquid phase, hydrogen as gas phase, and γ‐Fe 2O 3 magnetic powder as solid phase. The fluidized state of different bed positions was investigated by testing the transmissible laser current. Effects of magnetic field intensity and gas flow rate on layer expansion states of the MSB were analyzed by color diagrams. A Ru‐Zn‐B amorphous alloy was prepared by chemical reduction. Selective hydrogenation of benzene was carried out in the MSB by adjusting the contact time between the catalysts and reactants through variations of reaction temperature, magnetic field current, and liquid hourly space velocity. 相似文献
20.
We have synthesized Fe 3O 4 nanoparticles on mesoporous SBA-15 by an “in situ” approach. The synthesized nanocomposite material was well characterized using wide and low angle XRD, N 2 adsorption–desorption isotherm, TEM, FTIR, XPS, and VSM analysis. The Fe 3O 4@SBA-15 nanocomposite material was used as a magnetically recoverable catalyst (MRC) for three component coupling reaction of aldehyde, amine and alkyne. The reported catalyst was recycled up to five times without significant loss in its catalytic activity. 相似文献
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