查找使用阿拉丁产品的科研文献

Alkene-modified Fe3O4 nanoparticle-mediated construction of functionalized mesoporous poly(ionic liquid)s: Synergistic catalysis of mesoporous confinement effect and hydrogen proton for organic transformations

Zhong-Qiu Liu,Sheng-Nan Li,Qing-Shuai Zeng,Yu-Jing Liu,Jin-Mao You,An-Guo Ying

The preparation of mesoporous poly(ionic liquid)s (MPILs) is critically fundamental for the design of heterogeneous catalysts, whereas traditional methods are difficult to obtain these materials with both well-defined mesoporous structure and unique functionality. Here, HClO 4 -functionalized MPILs with well-defined mesoporous structure were successfully fabricated, in which the alkene-modified Fe 3 O 4 nanoparticles as structural reinforcer play a vital role for mesoporous structure formation. The MPILs were characterized by N 2 adsorption/desorption, scanning electron microscope (SEM), transmission Electron Microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibration sample magnetometry (VSM), and the results confirm that MPILs possess moderate surface area, well-defined mesoporosity, abundant active ionic centers, as well as efficient magnetic recovery. The resulting MPILs show excellent catalytic activity for condensation reaction and Knoevenagel condensation. The kinetic study reveals that the excellent catalytic activity of MPILs is attributed to the synergistic catalysis of mesoporous confinement effect and hydrogen proton from MPILs, albeit with mass transfer resistance produced by mesoporous channels. Further, the catalyst can be recovered using an external magnetic field and reused at least 10 times without a considerable decrease in its catalytic activity. Finally, alkene-modified Fe 3 O 4 nanoparticle-mediated mesoporous construction promotes a textural engineering approach to the development of novel mesoporous materials for other applications.

Facile preparation of the dendritic Fe3O4 with a core-shell microstructure in SiO2-B2O3-Al2O3-CaO-Fe2O3 glass-ceramic system for enhanced microwave absorbing performance

Xiaoyang Wang,Jianguo Huang,Hao Feng,Jinfeng Li,Zidie Pu,Xiangchun Yin

The hierarchical architecture constitutes one of the key factors affecting the performance of microwave absorbing materials (MAMs). Herein, core-shell Fe 3 O 4 with a dendritic hierarchical structure is fabricated successfully by the melting method in a SiO 2 -B 2 O 3 -Al 2 O 3 -CaO-Fe 2 O 3 multi-component system. The multiple transmission scattering absorption mechanism is mediated by the unique microstructure, thus improving the impedance matching and the microwave loss ability of the material. According to its reflection loss curve, the microwave absorption was efficiently optimized, yielding a minimum reflection loss (R L ) of − 54.26 dB when the thickness was 3.47 mm, and the effective bandwidth (R L   <10 dB) for electromagnetic wave reflectance reached 3.28 GHz (6.48–9.76 GHz) with a sample thickness of 1.8 mm. The present work adds new useful information for the designing of high-performance glass-ceramic MAMs.

Self-assembled Au/Fe3O4 nanoparticle-loaded phytic acid-graphene oxide composite foam with highly efficient catalytic performance for p-nitrophenol and o-nitroaniline organic pollutants

Ran Wang,Chong Cai,Di Wang,Zhiwei Liu,Lili Gao,Tifeng Jiao

In this work, a new type of self-assembled phytic acid-graphene oxide composite foam (PAGF) was prepared by hydrothermal method. In addition, Au nanoparticles (Au NPs) and Fe 3 O 4 particles were loaded onto PADF to obtain PAGF@Au&Fe 3 O 4 composite by a simple one-step method. The addition of graphene oxide (GO) can effectively prevent the agglomeration of Au NPs and weaken its surface passivation. The results of SEM, XRD, XPS and BET proved the successful preparation of the composite and its large specific surface area. Moreover, the synthesized PAGF@Au&Fe 3 O 4 composite showed good catalytic performance for p-nitrophenol (4-NP) and o-nitroaniline (2-NA) solutions with the rate constant (k) values of 0.0799 min −1 and 0.0546 min −1 , respectively. Due to the addition of Fe 3 O 4 , the composite exhibited good stability and recyclability, and maintained high catalytic efficiency after 8 cycles of catalytic process. The current work provides new ideas for developing novel graphene oxide-based composite materials and their catalytic degradation of organic pollutants.

Multi-catalysis induced by pulsed discharge plasma coupled with graphene-Fe3O4 nanocomposites for efficient removal of ofloxacin in water: Mechanism, degradation pathway and potential toxicity

He Guo,Zhen Li,Siying Lin,Dongsheng Li,Nan Jiang,Huijuan Wang,Jiangang Han,Jie Li

Herein, degradation of ofloxacin (OFX) by pulsed discharge plasma (PDP) coupled with multi-catalysis using graphene-Fe 3 O 4 nanocomposites was inspected. The graphene-Fe 3 O 4 nanocomposites were prepared by hydrothermal synthesis, and their morphology, specific surface area, chemical bond structure and magnetic property were characterized systematically. Compared with sole Fe 3 O 4 , the specific surface area of graphene-Fe 3 O 4 nanocomposites increased from 26.34 m 2 /g to 125.04 m 2 /g. The prepared graphene-Fe 3 O 4 nanocomposites had higher paramagnetism and the magnetic strength reached 66.05 emu/g, which was prone to separate from solution. Graphene-Fe 3 O 4 nanocomposites could further accelerate OFX degradation compared to sole Fe 3 O 4 . When graphene content was 18 wt%, graphene-Fe 3 O 4 nanocomposites exhibited the highest catalytic activity , and the removal efficiency of OFX enhanced from 65.0% (PDP alone) to 99.9%. 0.23 g/L dosage and acid solution were beneficial for OFX degradation. Higher stability of graphene-Fe 3 O 4 nanocomposites could be maintained although four times use. Graphene-Fe 3 O 4 nanocomposites could catalyze H 2 O 2 and O 3 to produce more ·OH. The degradation products of OFX were identified by liquid chromatography mass spectrometry (LC-MS) and ion chromatography (IC). According to the identified products and discrete Fourier transform (DFT), the degradation pathway was inferred. Further toxicity assessment of products manifested that the toxicity of oral rat 50% lethal dose (LD 50 ) and the developmental toxicity of OFX were reduced.

Au-coated Fe3O4 core-shell nanohybrids with photothermal activity for point-of-care immunoassay for lipoprotein-associated phospholipase A2 on a digital near-infrared thermometer

Guo Haixin,Su Xiaoping,Su Qingfu,Zhuang Wei,You Zhijiao

A portable photothermal immunoassay based on Au-coated magnetic Fe 3 O 4 core-shell nanohybrids (Au-Fe 3 O 4 ) was developed for point-of-care (POC) testing of lipoprotein-associated phospholipase A 2 (Lp-PLA 2 ) on a digital near-infrared (NIR) thermometer. Au-Fe 3 O 4 photothermal materials were first synthesized through reverse micelle method, and then functionalized with polyclonal rabbit anti-human Lp-PLA 2 antibody. A sandwiched immunoreaction was carried out in polyclonal mouse anti-human Lp-PLA 2 antibody-coated microplate using Au-Fe 3 O 4 -labeled antibody as the detection antibody. With formation of sandwich-type immunocomplex, the captured Au-Fe 3 O 4 on the plate converted the light into heat under an 808-nm laser irradiation (1.5 W cm −2 ), thereby resulting in the increasing temperature of the detection solution. The temperature variations relative to surrounding temperature was determined on a portable NIR thermometer. Several labeling protocols with gold nanoparticle, Fe 3 O 4 nanoparticle, or Au-Fe 3 O 4 nanohybrids were investigated for determination of Lp-PLA 2 and improved analytical features were achieved with the core-shell Au-Fe 3 O 4 nanohybrids. Under optimum conditions, Au-Fe 3 O 4 -based immunoassay exhibited good photothermal responses for the detection of Lp-PLA 2 with a dynamic linear range of 0.01–100 ng mL −1 at a low detection limit of 8.6 pg mL −1 . Good reproducibility and intermediate precision were less than 9.7%. Other biomarkers or proteins did not interfere with responses of this system. An acceptable accuracy was acquired for analysis of human serum sample between Au-Fe 3 O 4 -based photothermal immunoassay and commercialized human Lp-PLA 2 ELISA kit.

Polyethyleneimine coated Fe3O4 magnetic nanoparticles induce autophagy, NF-κB and TGF-β signaling pathway activation in HeLa cervical carcinoma cells via reactive oxygen species generation

Shuli Man,Miao Li,Jin Zhou,Haiyue Wang,Jinyan Zhang,Long Ma

Fe3O4 magnetic nanoparticles (MNPs), as one of the most intensively researched NPs, have a range of applications in cancer treatments. In current research, we have focused on the influences of MNPs on cancer cells. We chose polyethyleneimine (PEI) coated MNPs (PEI-MNPs) as a model and they are colloidally stable in biological media. It can be proved that PEI-MNPs result in autophagy induction via mTOR-Akt-p70S6 K and ATG7 signaling pathways. For the first time, we have reported that PEI-MNPs activate both NF-κB and TGF-β signaling, two key pro-inflammatory pathways, in cancer cells. More significantly, we have found that autophagy induction and NF-κB and TGF-β activation can be efficiently suppressed through the inhibition of PEI-MNP dependent reactive oxygen species (ROS) over-production. ROS are deemed as a ‘double edge sword’ for cancer cells, owing to the cancer-suppressing and cancer-promoting actions. Our findings would be useful for designing MNPs induced ROS anti-cancer strategies or diminishing long-term toxic effects.

Controllable conversion of Prussian blue@yeast bio-template into 3D cage-like magnetic Fe3O4@N-doped carbon absorbent and its cohesive regeneration by persulfate activation

Si Chen,Bo Bai,Yunhua He,Na Hu,Honglun Wang,Yourui Suo

A multitude of heteroatom-doped carbon adsorbents have been explored to cope with ever-growing organic pollution. However, development of these advanced carbon materials with adequate activity and stability remains challenging. Herein, unique 3D cage-like magnetic N-doped Fe3O4@C adsorbents were rationally constructed by a one-step pyrolysis of Prussian blue@yeast (PB@yeast) bio-templates. By using yeast as an available biological support, the prepared Fe3O4@C hybrids were demonstrated to provide a sufficient number of Fe, N and C atoms for the novel cage-like microstructures, making them a new type of Fe, N co-doped carbon absorbents with a facile preparation procedure and remarkable adsorption behavior. Rhodamine B (RhB) removal indicated that the prepared N-doped Fe3O4@C adsorbents displayed high adsorption capabilities in a near-neutral solution, and Fe3O4@C (1 : 0.11) exhibited a maximum adsorption capability of 257.06 mg g−1. More importantly, spent N-doped Fe3O4@C absorbents, which could be recovered by magnetic separation and cohesive persulfate (PS) activated photo-Fenton regeneration, showed excellent adsorption reusability and high stability even after 5 cycles. Overall, this paper presents a simple method for fabrication of a 3D cage-like magnetic N-doped Fe3O4@C adsorbent, which provides a significant guidance for the study of Fe, N co-doped carbon adsorbents towards dye wastewater treatment.

Synthesis of yolk-shell structure Fe3O4/P(MAA-MBAA)-PPy/Au/ void/TiO2 magnetic microspheres as visible light active photocatalyst for degradation of organic pollutants

Mingliang Ma,Yuying Yang,Wenting Li,Yong Ma,Zhouyu Tong,Weibo Huang,Liu Chen,Guanglei Wu,Huanli Wang,Ping Lyu

Yolk-shell magnetic Fe 3 O 4 /P(MAA-MBAA)-PPy/Au/void/TiO 2 microspheres have been prepared as visible light active photocatalyst . In this structure, the Fe 3 O 4 /P(MAA-MBAA)-PPy core-shell support provides magnetic properties for the catalyst and a large number of binding sites for the Au nanoparticles . In addition, coupling TiO 2 with Au nanoparticles can extend the range of absorbable sunlight and enhance electron hole separation. The test of degrading rhodamine B (RhB) under simulated visible light was used to verify the photocatalytic activity of the photocatalyst. The results showed that the photocatalyst exhibited favorable catalytic properties within 90 min in the case of using 4 mg itself. The improved performances were ascribed to the unique yolk-shell structure, which on the one hand greatly improves the light utilization, on the other hand favors full contact of the dye because of the porous appearance of the outer shell. Furthermore, the existence of magnetic core was beneficial to the recycling of the photocatalyst. And the recycling results demonstrated that the catalyst efficiency was maintained at 70.2% even after six recycling experiments. This work not only displays a new material for the degradation of organic dyes, but also provides a new approach for the synthesis of yolk-shell structure photocatalysts.

Magnetic solid-phase extraction based on Fe3O4/graphene oxide nanoparticles for the determination of malachite green and crystal violet in environmental water samples by HPLC

Leilei Zhang,Yiying Zhang,Yurong Tang,Xiaorong Li,Xinfeng Zhang,Chaobi Li,Shuxia Xu

Natural collagen fiber-enabled facile synthesis of carbon@Fe3O4 core–shell nanofiber bundles and their application as ultrahigh-rate anode materials for Li-ion batteries

Zerui Chen,Jianfei Zhou,Xiaoling Wang,Xuepin Liao,Xin Huang,Bi Shi

A C@Fe3O4 core–shell nanofiber bundle (C@Fe3O4NFB) was easily prepared using a natural collagen fiber (CF) as the biotemplate and carbon source. The as-prepared C@Fe3O4NFB features a continuous conductive pathway with dramatically accelerated electron and Li+ transport kinetics, thus exhibiting an ultrahigh-rate capability. Furthermore, the C@Fe3O4 core–shell structure is able to suppress the electrode pulverization due to the existence of the carbon nanofiber as an elastic buffering matrix, thus delivering long-term cycling stability. Based on electrochemical experiments, C@Fe3O4NFB delivered capacities of 839, 668, 422 and 301 mA h g−1 at current densities of 0.2, 1.0, 5.0 and 10.0 A g−1, respectively. At the current density of 1.0 A g−1, the reversible capacity of C@Fe3O4NFB is as high as 632 mA h g−1 in the 500th cycle, which accounts for 84.38% capacity of the 2nd cycle, suggesting a low capacity loss of 0.23 mA h g−1 per cycle. Even after 2000 cycles at 5.0 A g−1, the discharge capacity still reaches 354 mA h g−1. This biotemplated synthesis approach provides a novel and interesting route for fabricating ultrahigh-rate anode materials of LIBs.

Detection of Aβ oligomers based on magnetic-field-assisted separation of aptamer-functionalized Fe3O4 magnetic nanoparticles and BaYF5:Yb,Er nanoparticles as upconversion fluorescence labels

Ling-Feng Jiang,Bo-Cheng Chen,Ben Chen,Xue-Jian Li,Hai-Lin Liao,Hong-Miao Huang,Zhan-Jing Guo,Wen-Yan Zhang,Lin Wu

A sensitive and stable bioassay for the detection of Aβ oligomer (Aβo), a potentially promising candidate biomarker for Alzheimer's disease (AD) diagnosis, was developed using Fe 3 O 4 magnetic nanoparticles (MNPs) as the recognition and concentration elements and BaYF 5 :Yb,Er upconversion nanoparticles (UCNPs) as highly sensitive labels, conjugated with the Aβo aptamer (DNA1) and the complementary oligonucleotide of the Aβo aptamer (DNA2), respectively. The DNA1 hybridized with DNA2 to form the duplex structure on the surface of the MNPs/UCNPs nanocomposites probe. When the target Aβo was introduced, the aptamer DNA1 preferentially bound with Aβo and caused the dissociation of some complementary DNA2, liberating some UCNP-labeled complementary DNA2 and leading to a decreased upconversion fluorescent intensity on the surface of MNPs. The decreased fluorescence intensity of UCNPs was related to the concentration of Aβo in the range of 0.2–15   nM with a detection limit of 36 pM. The developed method then was successfully applied to measure Aβo in artificial cerebrospinal fluid. Benefiting from the magnetic separation and concentration effect of MNPs, the high sensitivity of UCNPs, as well as the selectivity and stability of the aptamer, the present strategy offered valuable information related to early diagnosis of AD process.

Hydrothermal synthesis of superparamagnetic and red luminescent bifunctional Fe3O4@Mn2+-doped NaYF4:Yb/Er core@shell monodisperse nanoparticles and their subsequent ligand exchange in water

Zhenli Qin,Sinan Du,Yang Luo,Zhijian Liao,Fang Zuo,Jianbin Luo,Dong Liu

We report the use of an efficient hydrothermal method to synthesize superparamagnetic and red luminescent bifunctional Fe 3 O 4 @Mn 2+ -doped NaYF 4 :Yb/Er nanoparticles (NPs) with core@shell structures via a seed-growth procedure. Oleic acid coated Fe 3 O 4 (OA-Fe 3 O 4 ) NPs were initially synthesized using a coprecipitation method. The as-synthesized OA-Fe 3 O 4 NPs were then used as seeds, on which the red upconversion luminescent shell (Mn 2+ -doped NaYF 4 :Yb/Er) was formed. Furthermore, hydrophobic to hydrophilic surface modification of the Fe 3 O 4 @Mn 2+ -doped NaYF 4 :Yb/Er NPs was achieved via a ligand exchange method where oleic acid was displaced by a PEG phosphate ligand [PEG   =   poly(ethylene glycol)]. These materials were characterized by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, and vibrating sample magnetometry (VSM). The Fe 3 O 4 cores were uniformly coated with a Mn 2+ -doped NaYF 4 :Yb/Er shell, and the bifunctional Fe 3 O 4 @Mn 2+ -doped NaYF 4 :Yb/Er NPs were monodispersed. Furthermore, the Fe 3 O 4 @Mn 2+ -doped NaYF 4 :Yb/Er NPs exhibited a saturated magnetization value of 6.2 emu/g and emitted red luminescence under a 980   nm laser. The obtained bifunctional Fe 3 O 4 @Mn 2+ -doped NaYF 4 :Yb/Er NPs may find potential applications in drug targeting, bioseparation, and diagnostic analysis. The synthetic method may be employed for the preparation of other bifunctional nanomaterials.