Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still car...Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.展开更多
Non-noble metal(NNM)catalysts have recently attracted intensive interest for their high catalytic performance towards oxygen reduction reaction(ORR)at low cost.Herein,a novel NNM catalyst was synthesized by the simple...Non-noble metal(NNM)catalysts have recently attracted intensive interest for their high catalytic performance towards oxygen reduction reaction(ORR)at low cost.Herein,a novel NNM catalyst was synthesized by the simple pyrolysis of carbon black,urea and a Fe-containing precursor,which exhibits excellent ORR catalytic activity,superior durability and methanol tolerance versus the Pt/C catalyst in both alkaline and acidic solutions.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD)characterizations demonstrate that the product is a nitrogen-doped hybrid of graphite encapsulated Fe/Fe3C nanoparticles and carbon black.X-ray photoelectron spectrum(XPS)and electrochemical analyses indicate that the catalytic performance and chemical stability correlate closely with a nitrogen-rich layer on the Fe/Fe3C nanoparticle after pyrolysis with presence of urea,leading to the same four-electron pathway towards ORR as the Pt/C catalyst.The hybrid is prospective to be an efficient ORR electrocatalyst for direct methanol fuel cells with high catalytic performance at low cost.展开更多
Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticl...Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.展开更多
Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 n...Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.展开更多
Peroxidase-like catalytic properties of Fe3O4 nanoparficles （NPs） with three different sizes, synthesized by chemical coprecipitation and sol-gel methods, were investigated by UV-vis spectrum analysis. By comparing ...Peroxidase-like catalytic properties of Fe3O4 nanoparficles （NPs） with three different sizes, synthesized by chemical coprecipitation and sol-gel methods, were investigated by UV-vis spectrum analysis. By comparing Fe3O4 NPs with average diameters of 11, 20, and 150 nm, we found that the catalytic activity increases with the reduced nanoparticle size. The electrochemical method to characterize the catalytic activity of Fe3O4 NPs using the response currents of the reaction product and substrate was also developed.展开更多
A versatile wet impregnation method was employed to conveniently and controllably deposit Fe_2O_3 nanoparticles on zeolites including commercial Y, mordenite and ZSM-5 with the similar framework Si/Al ratios and cryst...A versatile wet impregnation method was employed to conveniently and controllably deposit Fe_2O_3 nanoparticles on zeolites including commercial Y, mordenite and ZSM-5 with the similar framework Si/Al ratios and crystal sizes, respectively. The ultrafine Fe_2O_3 nanoparticles in size of 5 nm can be highly dispersed on zeolite Y matrix due to its much better wettability than ZSM-5 and mordenite. By using the obtained Fe_2O_3/zeolite composite as the heterogeneous Fenton-like catalysts, the degradation of phenol as a model reaction was systematically investigated, including the zeolite supports, particle size and dispersion of Fe_2O_3, and reaction conditions of H_2O_2 concentration, temperature, and pH value. The catalyst based on zeolite Y with Fe loading of 9% exhibited the best phenol degradation efficiency (> 90%)in neutral pH within 2 h. Its high catalytic activity in Fenton reaction can be attributed to the bifunctional properties of strong surface BrФnsted acidity and high reactivity of octahedral Fe^(3+) in the highlydispersed ultrafine Fe_2O_3 nanoparticles in size of 5 nm, which were the primary active centers to quickly decompose H_2O_2 into hydroxyl radicals. Since phenol degradation can be performed under mild conditions of ambient temperature (283-323 K) and a wide pH range (4.0-7.0), the catalysts can be easily recovered for recyclable use with stable degradation activity, which own the immense potential in deep treatment of organic pollutants in industrial wastewater.展开更多
In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erag...In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs展开更多
Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparti...Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy（TEM）,Fourier transform infrared（FTIR） spectrometry,X-ray diffraction（XRD） measurement,thermogravimetric analysis（TGA） and Vibrating sample magnetometry （VSM）,respectively.展开更多
Fe3O4 nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic micro-spheres dispersed in org...Fe3O4 nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic micro-spheres dispersed in organic medium glycol were gained and the mean size of Fe3O4 nanopowders was 33.7 nm. So it can be concluded that magnetic micro-sphere is made of a few Fe3O4 crystals. Many factors of modification were researched, such as the time of ball milling, the content of Fe3O4 and the content of KH570. The modification of Fe3O4 is relative to the time of ball milling, but the dominant function is affected by the content of Fe3O4 and KH570. When the content of Fe3O4 is known, there is a suitable content of KH570. Different content of Fe3O4 will make the different suitable content of KH570, but the range of latter is less than former, which is relative to the distribution of KH570 on Fe3O4 surface or in the solution.展开更多
We proposed a new way to synthesize a nanocomposite consisted of cementite Fe3C nanoparticles and amorphous carbon by radio frequency plasma-enhanced chemical vapor deposition. Transmission electron microscope images ...We proposed a new way to synthesize a nanocomposite consisted of cementite Fe3C nanoparticles and amorphous carbon by radio frequency plasma-enhanced chemical vapor deposition. Transmission electron microscope images show the existence of nanometric dark grains（Fe3C） embedded in a light matrix（amorphous carbon） in the samples. X-ray photoelectron spectroscopy experiment exhibit that the chemical bonding state in the films corresponded to sp3/sp2 amorphous carbon, sp^3 C-N（287.3 eV） and C15 in Fe3C（283.5 eV）. With increasing deposition time, the ratio of amorphous carbon increased. The magnetic measurements show that the value of in-lane coercivity increased with increasing carbon matrix concentration（from about 6.56× 10^3 A/m for film without carbon structures to approximately 2.77× 10^4 and 5.81 × 10^4 AJm for nanocomposite films at room temperature and 10 K, respectively）. The values of saturation magnetization for the synthesized nanocomposites were lower than that of the bulk Fe3C （ 140 Am^2/kg）.展开更多
The surface organic modification of Fe3O4 nanoparticles with silane coupling reagent KH570 was studied. The modified and unmodified nanoparticles were characterized by FT-IR, XPS and TEM. The spectra of FT-IR and XPS ...The surface organic modification of Fe3O4 nanoparticles with silane coupling reagent KH570 was studied. The modified and unmodified nanoparticles were characterized by FT-IR, XPS and TEM. The spectra of FT-IR and XPS revealed that KH570 was coated onto the surface of Fe3O4 nanoparticles to get Fe-O- Si bond and an organic coating layer also was formed. Fe3O4 nanoparticles were spheres partly with mean size of 18,8 nm studied by TEM, which was consistent with the result 17.9 nm calculated by Scherrer＇s equation. KH570 was adsorbed on surface and formed chemistry bond to be steric hindrance repulsion which prevented nanoparticles from reuniting. Then glycol-based Fe3O4 magnetic liquids dispersed stably was gained.展开更多
Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale...Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution p H, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the p H range from 4.0 to 9.0. Levofloxacin removal ratio increased with Fe3O4 MNP dose up to 1.0 g·L-1and with H2O2 concentration until reaching the maximum. Moreover, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.展开更多
Biodiesel is a green fuel which can replace diesel while addressing various issues such as scarcity of hydrocarbon fuels and environmental pollution to an extent. The high production cost of biodiesel and the recovery...Biodiesel is a green fuel which can replace diesel while addressing various issues such as scarcity of hydrocarbon fuels and environmental pollution to an extent. The high production cost of biodiesel and the recovery of the catalyst after the transesterification process are the major challenges to be addressed in biodiesel production. In the present work, a cheap and promising solid base oxide catalyst was synthesized from chicken eggshell by calcination at 900 ℃ forming catalyst eggshells(CES) and was impregnated with the nanomagnetic material(Fe3O4) to obtain Fe3O4 loaded catalytic eggshell(CES–Fe3O4). Fe3O4 nanomaterials were synthesized by co-precipitation method and were loaded in catalytic eggshell by sonication, for better recovery of the catalyst after transesterification process. CES–Fe3O4 material was characterized by Thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, a vibrating-sample magnetometer, Brunauer-Emmett-Teller, Dynamic light scattering, and Scanning electron microscopy. Biodiesel was synthesized by transesterification of Pongamia pinnata raw oil with 1:12 oil to methanol molar ratio and 2 wt% catalyst loading for 2 h at a temperature of 65 ℃ and yields were compared. The reusability of the catalyst was studied by the transesterification of the raw oil and its catalytic activity was found to be retained up to 7 cycles with a yield of 98%.展开更多
A magnetic sensor for detection of Pb^2＋ has been developed based on Fe/Fe3O4 nanoparticles modified by3-（3,4-dihydroxyphenyl）propionic acid（DHCA）. The carboxyl groups of DHCA have a strong affinity to coordinati...A magnetic sensor for detection of Pb^2＋ has been developed based on Fe/Fe3O4 nanoparticles modified by3-（3,4-dihydroxyphenyl）propionic acid（DHCA）. The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb^2＋ thus inducing the transformation of Fe/Fe3O4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time（T2） of the surrounding water protons. Upon addition of the different concentrations of Pb^2＋ to an aq. solution of DHCA functionalized Fe/Fe3O4 nanoparticles（DHCA-Fe/Fe3O4 NPs）（[Fe] = 90 mmol/L）, the change of T2 values display a good linear relationship with the concentration of Pb^2＋ from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb^2＋, DHCA-Fe/Fe3O4 NPs exhibited a high selectivity over other metal ions.展开更多
Magnetic nanoparticles （Fe304） were prepared by chemical precipitation method using Fe^2＋ and Fe^3＋ salts with sodium hydroxide in the nitrogen atmosphere. Fe3O4 nanoparticles were coated with human serum albumin...Magnetic nanoparticles （Fe304） were prepared by chemical precipitation method using Fe^2＋ and Fe^3＋ salts with sodium hydroxide in the nitrogen atmosphere. Fe3O4 nanoparticles were coated with human serum albumin（HSA） for magnetic resonance imaging as contrast agent. Characteristics of magnetic particles coated or uncoated were carried out using scanning electron microscopy and X-ray diffraction. Zeta potentials, package effects and distributions of colloid particles were measured to confirm the attachment of HSA on magnetic particles. Effects of Fe3O4 nanoparticles coated with HSA on magnetic resonance imaging were investigated with rats. The experimental results show that the adsorption of HSA on magnetic particles is very favorable to dispersing of magnetic Fe3O4 particles, while the sizes of Fe3O4 particles coated are related to the molar ratio of Fe3O4 to HSA. The diameters of the majority of particles coated are less than 100 nm. Fe3O4 nanoparticle coated with HSA has a good biocompatibility and low toxicity. This new contrast agent has some effects on the nuclear magnetic resonance imaging of liver and the lowest dosage is 20μmol/kg for the demands of diagnosis.展开更多
Magnetite （Fe3O4） nanoparticles with different sizes and shapes are synthesized by the thermal decomposition method. Two approaches, non-injection one-pot and hot-injection methods, are designed to investigate the g...Magnetite （Fe3O4） nanoparticles with different sizes and shapes are synthesized by the thermal decomposition method. Two approaches, non-injection one-pot and hot-injection methods, are designed to investigate the growth mechanism in detail. It is found that the size and shape of nanoparticles are determined by adjusting the precursor concentration and duration time, which can be well explained by the mechanism based on the LaMer model in our synthetic system. The monodisperse Fe3O4 nanoparticles have a mean diameter from 5nm to 16nm, and shape evolution from spherical to triangular and cubic. The magnetic properties are size-dependent, and Fe3O4 nanoparticles in small size about 5 nm exhibit superparamagnetie properties at room temperature and maximum saturation magnetization approaches to 78 emu/g, whereas Fe3O4 nanoparticles develop ferromagnetic properties when the diameter increases to about 16nm.展开更多
In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform inf...In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FT-IR）. The characterization results indicated that Fe3O4 NPs with regular crystal structure and a narrow of diameters had been synthesized successfully and had high purity. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The response surface methodology（RSM） based on Box–Behnken design（BBD） was employed to design and optimize individual and interactive effects of the four main independent parameters（catalyst loading, initial p H, reaction temperature and H2O2concentration） on decolorization efficiency of Orange II. A significant quadratic model（p-value 〈0.0001, R2= 0.9369） was derived using analysis of variance（ANOVA）. Optimum conditions were catalyst loading of 1.5 g/L, initial p H of 2.7, reaction temperature of 42 8C and H2O2 concentration of 22 mmol/L, respectively. The predicted decolorization rate under the optimum conditions as determined by the proposed model was 99.55%. Confirmatory tests were carried out and the decolorization rate of 99.49% was observed under the optimum conditions, which agreed well with the model prediction.展开更多
Fe3O4 magnetic nanoparticles were prepared by co-precipitation of Fe^2＋ and Fe^3＋ in an ammonia solution, and its size was about 36 nm measured by an atomic force microscope. Fe3O4 magnetic nanoparticles were modifi...Fe3O4 magnetic nanoparticles were prepared by co-precipitation of Fe^2＋ and Fe^3＋ in an ammonia solution, and its size was about 36 nm measured by an atomic force microscope. Fe3O4 magnetic nanoparticles were modified by L-dopa or dopamine using sonication method. The analysis of FTIR clearly indicated the formation of Fe-O-C bond. Direct immobilization of trypsin （EC： 3.4.21.4） on Fe3O4 magnetic nanoparticles with L-dopa and dopamine spacer was investigated using glutaraldehyde as a coupling agent. No significant changes in the size and magnetic property of the three kinds of magnetic nanoparticles linked with or without trypsin were observed. The existence of the spacer molecule on magnetic nanoparticles could greatly improve the activity and the storage stability of bound trypsin through increasing the flexibility of enzyme and changing the microenvironment on nanoparticles surface compared to the naked magnetic nanoparticles.展开更多
A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the ...A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the Fe3O4/GCE.In 0.4mol/L HAc-NaAc buffer solution（pH=5.0）,the electrode process of nimesulide was irreversible at bare GCE and Fe3O4/GCE.The Fe3O4/GCE exhibited a remarkable catalytic and enhancement effect on the reduction of nimesulide.The reduction peak potential of nimesulide shifted positively from-0.683 V at bare GCE to-0.625 V at Fe3O4/GCE,and the sensitivity was increased by ca.3 times.Some experimental conditions were optimized.The linear range between the peak current and the concentration of nimesulide was 2.6×10-6 ＂1.0×10-4mol/L（R=0.993） with a detection limit of 1.3×10-7mol/L.This method has been used to determine the content of nimesulide in medical tablets.The recovery was determined to be 96.9% ＂101.9% by means of standard addition method.The method is comparable to UV-Vis spectrometry.展开更多
基金supported by the National Natural Science Foundation of China (U1303291)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R46)
文摘Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.
基金supported financially by the National Natural Science Foundation of China (No.51874051)the Natural Science Foundation of Guangxi Province (Nos.2015GXNSFAAI39283 and 2016GXNSFAA380107)
文摘Non-noble metal(NNM)catalysts have recently attracted intensive interest for their high catalytic performance towards oxygen reduction reaction(ORR)at low cost.Herein,a novel NNM catalyst was synthesized by the simple pyrolysis of carbon black,urea and a Fe-containing precursor,which exhibits excellent ORR catalytic activity,superior durability and methanol tolerance versus the Pt/C catalyst in both alkaline and acidic solutions.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD)characterizations demonstrate that the product is a nitrogen-doped hybrid of graphite encapsulated Fe/Fe3C nanoparticles and carbon black.X-ray photoelectron spectrum(XPS)and electrochemical analyses indicate that the catalytic performance and chemical stability correlate closely with a nitrogen-rich layer on the Fe/Fe3C nanoparticle after pyrolysis with presence of urea,leading to the same four-electron pathway towards ORR as the Pt/C catalyst.The hybrid is prospective to be an efficient ORR electrocatalyst for direct methanol fuel cells with high catalytic performance at low cost.
文摘Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.
基金Project(2011JQ028)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(2008SK3114,2010SK3113)supported by Hunan Provincial Science&Technology Plan,China+2 种基金Project(B2007086)supported by Science&Research Funds of Hunan Health Department,ChinaProject(12JJ5057)supported by Natural Science Foundation of Hunan Province,ChinaProjects(XCX1119,XCX12073)supported by University Students Innovative Experiment Plan Project of Hunan Agricultural University,China
文摘Highly biocompatible superparamagnetic Fe3O4 nanoparticles were synthesized by amide of folic acid （FA） ligands and the NH2-group onto the surface of Fe3O4 nanoparticles. The as-synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. The in vivo labeling effect of folate-conjugated Fe3O4 nanoparticles on the hepatoma cells was investigated in tumor-bearing rat. The results demonstrate that the as-prepared nanoparticles have cubic structure of Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm at a saturation magnetization of 51 A·m2/kg. These nanoparticles possess good physiological stability, low cytotoxicity on human skin fibroblasts and negligible effect on Wistar rats at the concentration as high as 3 mg/kg body mass. The folate-conjugated Fe3O4 nanoparticles could be effectively mediated into the human hepatoma Bel 7402 cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is in favor of the tumor cells labeling, tracing, magnetic resonance imaging （MRI） target detection and magnetic hyperthermia.
基金This work was supported by the National Natural Science Foundation of China （Nos. 90406023 and 60571031）；National Important Science Research Program of China （Nos. 2006CB933206 and 2006CB705606）.
文摘Peroxidase-like catalytic properties of Fe3O4 nanoparficles （NPs） with three different sizes, synthesized by chemical coprecipitation and sol-gel methods, were investigated by UV-vis spectrum analysis. By comparing Fe3O4 NPs with average diameters of 11, 20, and 150 nm, we found that the catalytic activity increases with the reduced nanoparticle size. The electrochemical method to characterize the catalytic activity of Fe3O4 NPs using the response currents of the reaction product and substrate was also developed.
基金sponsored by Shanghai Pujiang Program, China (No. 16PJ1401100)the Shanghai Committee of Science and Technology, China (No.15ZR1402000)+3 种基金Key Basic Research Program of Science and Technology Commission of Shanghai Municipality (No. 17JC1400100)the NSF of China(No. 21673048)National Youth Top Talent Support Program of National High-Level Personnel of Special Support Program (Youth Top-notch Talent Support Program)the State Key Laboratory of Transducer Technology of China (No. SKT1503)
文摘A versatile wet impregnation method was employed to conveniently and controllably deposit Fe_2O_3 nanoparticles on zeolites including commercial Y, mordenite and ZSM-5 with the similar framework Si/Al ratios and crystal sizes, respectively. The ultrafine Fe_2O_3 nanoparticles in size of 5 nm can be highly dispersed on zeolite Y matrix due to its much better wettability than ZSM-5 and mordenite. By using the obtained Fe_2O_3/zeolite composite as the heterogeneous Fenton-like catalysts, the degradation of phenol as a model reaction was systematically investigated, including the zeolite supports, particle size and dispersion of Fe_2O_3, and reaction conditions of H_2O_2 concentration, temperature, and pH value. The catalyst based on zeolite Y with Fe loading of 9% exhibited the best phenol degradation efficiency (> 90%)in neutral pH within 2 h. Its high catalytic activity in Fenton reaction can be attributed to the bifunctional properties of strong surface BrФnsted acidity and high reactivity of octahedral Fe^(3+) in the highlydispersed ultrafine Fe_2O_3 nanoparticles in size of 5 nm, which were the primary active centers to quickly decompose H_2O_2 into hydroxyl radicals. Since phenol degradation can be performed under mild conditions of ambient temperature (283-323 K) and a wide pH range (4.0-7.0), the catalysts can be easily recovered for recyclable use with stable degradation activity, which own the immense potential in deep treatment of organic pollutants in industrial wastewater.
基金Supported by the National Natural Science Foundation of China （21276124）, the Research Project of Natural Science for Universities Affiliated to Jiangsu Province （10KJB530002）, Key Projects in the National Science ＆ Technology Pillar Pro-gram （2011BAE07B09-3）, the Jiangsu Provincial Science and Technology Support Program （BE2011831）, and the State High Technology Research and Development Prograr of China （2011AA02A201）.
文摘In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs
基金financially supported by the Guangdong Natural Science Foundation(No.020891)
文摘Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin（CM-β-CD） modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy（TEM）,Fourier transform infrared（FTIR） spectrometry,X-ray diffraction（XRD） measurement,thermogravimetric analysis（TGA） and Vibrating sample magnetometry （VSM）,respectively.
基金This work was financially supported by the Graduate Innovation Plan Projects of Jiangsu Province in 2005.
文摘Fe3O4 nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic micro-spheres dispersed in organic medium glycol were gained and the mean size of Fe3O4 nanopowders was 33.7 nm. So it can be concluded that magnetic micro-sphere is made of a few Fe3O4 crystals. Many factors of modification were researched, such as the time of ball milling, the content of Fe3O4 and the content of KH570. The modification of Fe3O4 is relative to the time of ball milling, but the dominant function is affected by the content of Fe3O4 and KH570. When the content of Fe3O4 is known, there is a suitable content of KH570. Different content of Fe3O4 will make the different suitable content of KH570, but the range of latter is less than former, which is relative to the distribution of KH570 on Fe3O4 surface or in the solution.
基金Supported by the National Natural Science Foundation of China(No.50832001)the Science and Technology Develop-ment Program of Jilin Province, China(No.20070501)
文摘We proposed a new way to synthesize a nanocomposite consisted of cementite Fe3C nanoparticles and amorphous carbon by radio frequency plasma-enhanced chemical vapor deposition. Transmission electron microscope images show the existence of nanometric dark grains（Fe3C） embedded in a light matrix（amorphous carbon） in the samples. X-ray photoelectron spectroscopy experiment exhibit that the chemical bonding state in the films corresponded to sp3/sp2 amorphous carbon, sp^3 C-N（287.3 eV） and C15 in Fe3C（283.5 eV）. With increasing deposition time, the ratio of amorphous carbon increased. The magnetic measurements show that the value of in-lane coercivity increased with increasing carbon matrix concentration（from about 6.56× 10^3 A/m for film without carbon structures to approximately 2.77× 10^4 and 5.81 × 10^4 AJm for nanocomposite films at room temperature and 10 K, respectively）. The values of saturation magnetization for the synthesized nanocomposites were lower than that of the bulk Fe3C （ 140 Am^2/kg）.
基金the Natural Science Fund of Jiangsu province (No.BK2007586)Jiangsu Planned Projects(No.0701012B)for Postdoctoral Research Funds
文摘The surface organic modification of Fe3O4 nanoparticles with silane coupling reagent KH570 was studied. The modified and unmodified nanoparticles were characterized by FT-IR, XPS and TEM. The spectra of FT-IR and XPS revealed that KH570 was coated onto the surface of Fe3O4 nanoparticles to get Fe-O- Si bond and an organic coating layer also was formed. Fe3O4 nanoparticles were spheres partly with mean size of 18,8 nm studied by TEM, which was consistent with the result 17.9 nm calculated by Scherrer＇s equation. KH570 was adsorbed on surface and formed chemistry bond to be steric hindrance repulsion which prevented nanoparticles from reuniting. Then glycol-based Fe3O4 magnetic liquids dispersed stably was gained.
基金Supported by the National Natural Science Foundation of China(51009115)Shaanxi Provincial Department of Education Key Laboratory Project(13JS067)+2 种基金the Hall of Shaanxi Province Science and Technology(2013JK0881)the Research Plan Project of Water Resources Department of Shaanxi Province(2013slkj-07)the Innovation of Science and Technology Fund of Xi'an University of Technology(211302)
文摘Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution p H, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the p H range from 4.0 to 9.0. Levofloxacin removal ratio increased with Fe3O4 MNP dose up to 1.0 g·L-1and with H2O2 concentration until reaching the maximum. Moreover, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.
文摘Biodiesel is a green fuel which can replace diesel while addressing various issues such as scarcity of hydrocarbon fuels and environmental pollution to an extent. The high production cost of biodiesel and the recovery of the catalyst after the transesterification process are the major challenges to be addressed in biodiesel production. In the present work, a cheap and promising solid base oxide catalyst was synthesized from chicken eggshell by calcination at 900 ℃ forming catalyst eggshells(CES) and was impregnated with the nanomagnetic material(Fe3O4) to obtain Fe3O4 loaded catalytic eggshell(CES–Fe3O4). Fe3O4 nanomaterials were synthesized by co-precipitation method and were loaded in catalytic eggshell by sonication, for better recovery of the catalyst after transesterification process. CES–Fe3O4 material was characterized by Thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, a vibrating-sample magnetometer, Brunauer-Emmett-Teller, Dynamic light scattering, and Scanning electron microscopy. Biodiesel was synthesized by transesterification of Pongamia pinnata raw oil with 1:12 oil to methanol molar ratio and 2 wt% catalyst loading for 2 h at a temperature of 65 ℃ and yields were compared. The reusability of the catalyst was studied by the transesterification of the raw oil and its catalytic activity was found to be retained up to 7 cycles with a yield of 98%.
基金supported by National Natural Science Foundation of China (Nos. 21271130 and 21371122)Shanghai Science and Technology Development Fund (Nos. 12ZR1421800 and 13520502800)International Joint Laboratory on Resource Chemistry (IJLRC)
文摘A magnetic sensor for detection of Pb^2＋ has been developed based on Fe/Fe3O4 nanoparticles modified by3-（3,4-dihydroxyphenyl）propionic acid（DHCA）. The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb^2＋ thus inducing the transformation of Fe/Fe3O4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time（T2） of the surrounding water protons. Upon addition of the different concentrations of Pb^2＋ to an aq. solution of DHCA functionalized Fe/Fe3O4 nanoparticles（DHCA-Fe/Fe3O4 NPs）（[Fe] = 90 mmol/L）, the change of T2 values display a good linear relationship with the concentration of Pb^2＋ from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb^2＋, DHCA-Fe/Fe3O4 NPs exhibited a high selectivity over other metal ions.
文摘Magnetic nanoparticles （Fe304） were prepared by chemical precipitation method using Fe^2＋ and Fe^3＋ salts with sodium hydroxide in the nitrogen atmosphere. Fe3O4 nanoparticles were coated with human serum albumin（HSA） for magnetic resonance imaging as contrast agent. Characteristics of magnetic particles coated or uncoated were carried out using scanning electron microscopy and X-ray diffraction. Zeta potentials, package effects and distributions of colloid particles were measured to confirm the attachment of HSA on magnetic particles. Effects of Fe3O4 nanoparticles coated with HSA on magnetic resonance imaging were investigated with rats. The experimental results show that the adsorption of HSA on magnetic particles is very favorable to dispersing of magnetic Fe3O4 particles, while the sizes of Fe3O4 particles coated are related to the molar ratio of Fe3O4 to HSA. The diameters of the majority of particles coated are less than 100 nm. Fe3O4 nanoparticle coated with HSA has a good biocompatibility and low toxicity. This new contrast agent has some effects on the nuclear magnetic resonance imaging of liver and the lowest dosage is 20μmol/kg for the demands of diagnosis.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51571135,11274214 and 61434002the Special Funds of Shanxi Scholars Program under Grant No IRT1156+1 种基金Collaborative Innovation Center for Shanxi Advanced Permanent Materials and Technologythe Special Funds of the Ministry of Education of China under Grant No 20121404130001
文摘Magnetite （Fe3O4） nanoparticles with different sizes and shapes are synthesized by the thermal decomposition method. Two approaches, non-injection one-pot and hot-injection methods, are designed to investigate the growth mechanism in detail. It is found that the size and shape of nanoparticles are determined by adjusting the precursor concentration and duration time, which can be well explained by the mechanism based on the LaMer model in our synthetic system. The monodisperse Fe3O4 nanoparticles have a mean diameter from 5nm to 16nm, and shape evolution from spherical to triangular and cubic. The magnetic properties are size-dependent, and Fe3O4 nanoparticles in small size about 5 nm exhibit superparamagnetie properties at room temperature and maximum saturation magnetization approaches to 78 emu/g, whereas Fe3O4 nanoparticles develop ferromagnetic properties when the diameter increases to about 16nm.
基金financially supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20114219110002)Fund from Coal Conversion and New Carbon Materials Hubei Key Laboratory(Wuhan University of Science and Technology)(No.WKDM201107)Educational Commission of Hubei Province of China(No.D20131107)
文摘In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FT-IR）. The characterization results indicated that Fe3O4 NPs with regular crystal structure and a narrow of diameters had been synthesized successfully and had high purity. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The response surface methodology（RSM） based on Box–Behnken design（BBD） was employed to design and optimize individual and interactive effects of the four main independent parameters（catalyst loading, initial p H, reaction temperature and H2O2concentration） on decolorization efficiency of Orange II. A significant quadratic model（p-value 〈0.0001, R2= 0.9369） was derived using analysis of variance（ANOVA）. Optimum conditions were catalyst loading of 1.5 g/L, initial p H of 2.7, reaction temperature of 42 8C and H2O2 concentration of 22 mmol/L, respectively. The predicted decolorization rate under the optimum conditions as determined by the proposed model was 99.55%. Confirmatory tests were carried out and the decolorization rate of 99.49% was observed under the optimum conditions, which agreed well with the model prediction.
基金the Key Technologies R&D Program of Hubei Province(No.2005AA301B14)
文摘Fe3O4 magnetic nanoparticles were prepared by co-precipitation of Fe^2＋ and Fe^3＋ in an ammonia solution, and its size was about 36 nm measured by an atomic force microscope. Fe3O4 magnetic nanoparticles were modified by L-dopa or dopamine using sonication method. The analysis of FTIR clearly indicated the formation of Fe-O-C bond. Direct immobilization of trypsin （EC： 3.4.21.4） on Fe3O4 magnetic nanoparticles with L-dopa and dopamine spacer was investigated using glutaraldehyde as a coupling agent. No significant changes in the size and magnetic property of the three kinds of magnetic nanoparticles linked with or without trypsin were observed. The existence of the spacer molecule on magnetic nanoparticles could greatly improve the activity and the storage stability of bound trypsin through increasing the flexibility of enzyme and changing the microenvironment on nanoparticles surface compared to the naked magnetic nanoparticles.
基金Supported by the National Natural Science Foundation of China(No.21065001)the Natural Science Foundation of Guangxi Province,China(Nos.0639025,0991084)+2 种基金the Support Program for 100 Young and Middle-aged Disciplinary Leaders in Higher Education Institutions of Guangxi Province,China(No.RC20060703005)the Project of Key Laboratory of Development and Application of Forest Chemicals of Guangxi Province,China(No.GXFC08-06)the Fund of Education Department of Guangxi Province,China(No.200812MS074)
文摘A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the Fe3O4/GCE.In 0.4mol/L HAc-NaAc buffer solution（pH=5.0）,the electrode process of nimesulide was irreversible at bare GCE and Fe3O4/GCE.The Fe3O4/GCE exhibited a remarkable catalytic and enhancement effect on the reduction of nimesulide.The reduction peak potential of nimesulide shifted positively from-0.683 V at bare GCE to-0.625 V at Fe3O4/GCE,and the sensitivity was increased by ca.3 times.Some experimental conditions were optimized.The linear range between the peak current and the concentration of nimesulide was 2.6×10-6 ＂1.0×10-4mol/L（R=0.993） with a detection limit of 1.3×10-7mol/L.This method has been used to determine the content of nimesulide in medical tablets.The recovery was determined to be 96.9% ＂101.9% by means of standard addition method.The method is comparable to UV-Vis spectrometry.
