- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fe <sub/>3</sub> O <sub/>4</sub> nanoparticles as the saturable absorber for a mode-locked fiber laser at 1558 nm
摘要： We demonstrated a mode-locked erbium doped fiber laser (EDFL) operating at 1558 nm by exploiting ferroferric-oxide nanoparticles (FONPs) as the saturable absorber (SA) material. FONPs, with an average diameter of ~20 nm, were prepared by a thermal decomposition method, then mixed with sodium carboxymethylcelluose to form an FONP film. The FONP SA was fabricated through a sandwiched FONP film between two fiber connectors. By inserting the FONPs SA into an EDFL cavity pumped by a 980 nm laser diode, stable passive mode-locking was achieved with a threshold pump power of ~120 mW. The obtained mode-locked laser had a central wavelength of ~1558 nm, a spectral bandwidth of ~0.8 nm, a pulse width of ~4.35 ns, and a repetition rate of ~37.32 MHz. Furthermore, a maximum average power of ~17 mW was obtained for a pump power of 340 mW. To the best of our knowledge, this is the first time that it has been demonstrated that FONPs can be used for constructing mode-locked fiber lasers.
关键词： mode-locked,fibre laser,Fe3O4 nanoparticles,saturable absorber (SA)
更新于2025-11-28 14:23:57
-
Visible-Light Induced Photodegradation of Organic Contaminants in Water Using Fe3O4 Nanoparticles Modified Polypyrrole/Fly Ash Cenosphere Composite
摘要： Ternary nano-composites of polypyrrole/iron oxide/fly ash cenosphere (PPY/Fe3O4/FAC) were synthesized and used as magnetic photocatalyst. The synergistic effect of FAC, a buoyant carrier and polypyrrole, a conducting polymer enhanced the photocatalytic activity. Different composites were synthesized by varying the concentration of Fe3O4 and FAC to evaluate its effect on the photocatalytic properties of composites. The presence of Fe in Fe2+ and Fe3+ oxidation states at binding energies of 709.3 and 711.4 eV respectively was depicted by XPS curve. PPY/Fe3O4/FAC (1 : 3) composite showed the highest photocatalytic activity with rate constant (k) 0.0058 min–1. The removal efficiency of BPA was found to be around 75% and ~62% total organic content (TOC) was eliminated at optimized conditions from the solution. Transmission electron microscopy (TEM) showed the cluster morphology of the PPY/Fe3O4/FAC nano-composites with ~6–10 nm size of Fe3O4. X-ray diffraction studies elucidated the characteristic peaks of both PPY and Fe3O4 at 2θ ~ 20°–30°, and 26.04°, respectively in the composites which also confirmed the interaction of PPY with Fe3O4.
关键词： photo-degradation,polypyrrole,XPS,Fe3O4,fly ash cenosphere
更新于2025-11-21 11:18:25
-
Effective Removal of Tetracycline by Using Biochar Supported Fe3O4 as a UV-Fenton Catalyst
摘要： Novel Fe3O4-decorate hierarchical porous carbon skeleton derived from maize straw(Fe3O4@MSC) was synthesized by a facile co-precipitation process and a calcination process, which was developed as a UV assisted heterogeneous Fenton-like catalyst. The as-synthesized catalysts were characterized via X-ray powder diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), Brunauer-Emmet-Teller(BET) and vibrating sample magnetometer(VSM) at room temperature. The morphology and structure analysis revealed that the as-prepared Fe3O4@MSC retained the original pore morphology of the maize straw material. The non-uniform polyhedral Fe3O4 grew on the whole surface of the MSC, which reduced the aggragation of Fe3O4 and provided more active sites to strengthen the UV-assisted Fenton-like reaction. As a result, the tetracycline(TC) degradation efficiency after 40 min reaction and total organic carbon(TOC) removal efficiency after 2 h reaction of Fe3O4@MSC catalyzing UV-Fenton system reached 99.2% and 72.1%, respectively, which were more substantial than those of Fe3O4@MSC/H2O2(31.5% and 2%), UV/H2O2 system(68% and 23.4%) and UV/Fe3O4/H2O2(80% and 37.5%). The electron spin resonance(ESR) results showed that the ?OH played an important role in the catalytic reaction. A possible degradation pathway of TC was proposed on the basis of the identified intermediates. Overall, the UV assisted heterogeneous Fenton-like process in Fe3O4@MSC improved the cycle of Fe3+/Fe2+ and activated the interfacial catalytic site, which eventually realized the enhancement of degradation and mineralization to tetracycline.
关键词： Degradation of tetracycline,Heterogeneous Fenton-like catalyst,Fe3O4,Carbon skeleton of maize straw,UV irradiation
更新于2025-11-14 17:04:02
-
Direct synthesis of ultrasmall and stable magnetite nanoparticles coated with one single carbon layer for sensitive surface-enhanced Raman scattering
摘要： Ultrasmall spherical magnetite nanoparticles (Fe3O4 NPs) coated with one single carbon layer (Fe3O4@1C NPs) were directly synthesized by a simple, fast one-step hydrothermal reaction at low temperature (200℃). The as-synthesized Fe3O4@1C NPs were easily separated and purified from the resultant mixture, without the need for any additional energy input and chemicals. The as-purified Fe3O4@1C NPs not only displayed typical superparamagnetic behavior but also exhibited quite good long-term stability after being exposed to the open air under the room conditions for more than 2 months. Importantly, the long-term stored Fe3O4@1C NPs exhibited a highly sensitive surface-enhanced Raman spectroscopy (SERS) response toward Rhodamine-b (RdB) molecules with low concentration. The multifunctional and recyclable Fe3O4@1C NPs presented a prospective application for the selective enrichment and sensitive SERS detection of chemical and biomolecular assays.
关键词： coated with one single carbon layer (Fe3O4@1C NPs),Dehydration reaction,Saturation magnetization,Long-term stability,Magnetite nanoparticles (Fe3O4 NPs)
更新于2025-11-14 17:03:37
-
Ultraviolet light assisted heterogeneous Fenton degradation of tetracycline based on polyhedral Fe3O4 nanoparticles with exposed high-energy {110} facets
摘要： Polyhedral Fe3O4 nanoparticles (NPs) with exposed high-energy {110} facets were synthesized by hydro-thermal method using ferrous sulfate and sodium thiosulfate as precursor at 140 °C. The as-synthesized catalysts were characterized via X-ray powder diffraction (XRD), electro impedance spectra (EIS), scanning electron microscope (SEM), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) at room temperature. The well-defined Fe3O4 NPs with exposed high-energy {110} facets distributed a wide size, and the percentage of {110} facets was approximately 38.5% for single Fe3O4 NPs crystal. The synergistic effect of UV irradiation and the polyhedral Fe3O4 NPs improved the photodegradation efficiency of tetracycline (TC). The degradation efficiency of polyhedral Fe3O4 NPs catalyzing UV-Fenton system reached 96.7% after 60 min reaction, which was more substantial than polyhedral Fe3O4/H2O2 system (40%) and spherical Fe3O4 NPs catalyzing UV-Fenton system (28%) after 60 min reaction. The TOC degradation efficiency reached 56.5% for polyhedral Fe3O4 NPs catalyzing UV-Fenton after 120 min reaction, while UV/H2O2 system and spherical Fe3O4 NPs catalyzing UV-Fenton was 36.0% and 22.1% respectively after 120 min reaction. Moreover, polyhedral Fe3O4 NPs catalyzing UV-Fenton system exhibited an extremely wide pH range (from 3.0 to 9.0) for efficient degradation of TC. Simultaneously, the extraordinary high degradation efficiency was based on 10 mM H2O2 concentration, which had low requirement for H2O2. Further, the polyhedral Fe3O4 NPs could be reused for five consecutive cycles while still achieving at 91.7% of its original degradation efficiency and recycled under a magnetic field along with excellent chemical stability. Ultraviolet light assisted heterogeneous Fenton in the polyhedral Fe3O4 NPs system improved the ?OH and O2?- production efficiency and Fe(III)/Fe(II) redox cycle, which consequently achieved an excellent degradation efficiency.
关键词： heterogeneous UV-Fenton,Polyhedral Fe3O4 nanoparticles,high-energy {110} facets,tetracycline degradation
更新于2025-11-14 17:03:37
-
Magnetically Recoverable PEI/Titanate@Fe3O4 Photocatalysts: Fabrication and Photocatalytic Properties
摘要： The magnetically separable ternary polyetherimide/titanate@Fe3O4 (PTF) photocatalysts of special heterostructure between magnetite (Fe3O4) microspheres and titanates nanosheets modified by polyetherimide (PEI) were successfully fabricated via a simple facile hydrothermal deposition method. The as-prepared photocatalysts were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscopy and UV-vis diffuse reflectance spectroscopy etc. The results showed that the as-fabricated material had a structure of Fe3O4 microspheres coated with titanates nanosheets modified by PEI. The special interfacial contact between 3D microsphere and 2D nanosheets in the nanoarchitectures was formed via electrostatic attraction. Furthermore, the resulted photocatalysts were tested by degradation reaction of methylene blue under visible light irradiation and demonstrated an enhanced performance than the pure Fe3O4 microspheres, and the photocatalytic activity enhanced with the molar ratio of Fe3O4 microspheres and modified titanate gradually, which was attributed to the expansion of the surface area and the different electrostatic contact between the Fe3O4 microspheres and titanate nanosheets. Moreover, the obtained results revealed the high yield magnetic separation and efficient reusability of PTF-5 (96.7%) over 3 times reuse.
关键词： titanate,Fe3O4 microspheres,recyclability,photocatalyst,polyetherimide
更新于2025-09-23 15:23:52
-
A magnetic and carbon dot based molecularly imprinted composite for fluorometric detection of 2,4,6-trinitrophenol
摘要： A magnetic molecularly imprinted composite was prepared by reverse microemulsion using carbon dots (CDs), Fe3O4 as the co-nucleus, and a molecularly imprinted polymer (MIP; with 2,4,6-trinitrophenol as the template) acting as recognition sites. The composite of type CD/Fe3O4@MIPs was characterized by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), zeta potentiometric analysis, X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results showed that the composite MIP has a spherical shape with average diameter of 200 nm. They also showed that the composite contains core-shell structures with several Fe3O4 nanoparticles and CDs embedded in each of the microsphere. The composite can extract 2,4,6-trinitrophenol (TNP) and has an imprinting factor of 3.6. It has high selectivity and sensitivity for TNP which acts as a quencher of the fluorescence of the CDs (with excitation/emission maxima at 370/470 nm). The limit of detection of this fluorometric TNP assay is 0.5 nM. The method was successfully applied to the determination of TNP in spiked tap water and river water samples, and recoveries ranged from 89.4% to 108.5% (with an RSD of <6%).
关键词： Fluorescence quenching,Fe3O4 nanoparticles,Stern-Volmer plot,Environmental pollutants,Reverse microemulsion method,Selective recognition,Molecularly imprinting
更新于2025-09-23 15:23:52
-
Functionalization of silicon nanowires by iron oxide and copper for degradation of phenol
摘要： Iron oxide (Fe3O4) and copper-functionalized silicon nanowires (SiNWs) from silicon powder mesh < 500 with a spherical structure have been successfully synthesized as a heterogeneous catalyst for the degradation of phenol. This synthesized catalyst was prepared by nanosilicon wire powders. SiNWs have attracted much attention due their potential application in nanoscale devices such as field effect transistors, chemical or biological sensors, battery electrodes and photovoltaics. The SiNW properties were reinforced by functionalization. The synthesis of this catalyst was done by an in situ method for the decoration of SiNWs. Magnetic metal oxide compounds have been chosen not only to accelerate the catalyst recovery but also to improve the time duration of pollution elimination. Also, Cu nanoparticles were added in order to evaluate the catalytic property. In this work, the maximum amount of phenol degradation was obtained near 99.99%. Hybrid surface morphologies were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, the Brunauer–Emmette–Teller model and high-performance liquid chromatography.
关键词： Mesoporous,Fe3O4–Cu-SiNWs catalyst,Phenol degradation,Sphere
更新于2025-09-23 15:23:52
-
Gold-Iron Oxide Yolk-Shell Nanoparticles (YSNPs) as magnetic probe for Fluorescence-based detection of 3 base mismatch DNA
摘要： Seed-mediated Gold-Iron oxide yolk-shell nanoparticles (YSNPs) were synthesized and functionalized with cy5 attached- thiolated single strand DNA probe for the detection of mutated DNA. The optimum concentration of thiolated DNA determined from a bathochromic shift of surface plasmon resonance (SPR) peak, was 0.177μM. The effect of pH (2 to 10), temperature (4, 37, 60 and 100 °C), and ionic strengths (1 M to 4 M) on the stability of ssDNA probe tethered YSNPs, studied with the assistance of flocculation parameter. The detection of mutation in DNA was possible using such ssDNA probe functionalized and stabilized nanoparticles. The hybridization of the oligonucleotide probe with the complementary, non-complementary and mutated DNA strands are determined via their respective intensities of the fluorescence of cy5, an efficient fluorescent marker. The intensities help in the comprehension of the specificity of the system. The report predicts controlled efficiency of hybridization with the aid of Hamaker constant, which is determined as 1.15 x 10-20 J for DNA functionalized YSNPs. The minimum concentration of target DNA detected using this methodology was 1.2×10-11 mol/L.
关键词： Plasmonics,Fluorescence,YSNPs,Au-Fe3O4,Point mutations
更新于2025-09-23 15:23:52
-
Ultraviolet-light-assisted heterogeneous Fenton reaction of Ag-Fe3O4/graphene composites for the degradation of organic dyes
摘要： In this study, Fe3O4/graphene and Ag-Fe3O4/graphene composites with varying content of graphene and Ag were prepared and used as a heterogeneous Fenton catalyst for the degradation of MO and MB under UV-light irradiation. The physicochemical properties of the obtained catalysts were used for the Fenton reaction. In addition, the effects of graphene and Ag content, pH, H2O2 concentration, catalyst loading, and initial MO and MB concentrations on the degradation by the UV-Fenton process were evaluated. Results revealed that the highest removal efficiency of MO and MB is achieved at graphene and Ag concentrations of 10 and 25 wt%, respectively. Furthermore, Ag-Fe3O4/graphene composites were used to assess the degradation of a mixture of MO and MB and other anionic and cationic dyes. Results revealed that Ag-Fe3O4/graphene composites can be used as a broad-spectrum catalyst with good efficiency for the removal of several dye contaminants in water. Moreover, the effect of the addition of ascorbic acid (AA) on dye degradation was investigated. AA accelerated the degradation of organic dyes compared to that without AA. The obtained results revealed that Ag-Fe3O4/graphene composites exhibit stable catalytic activity and reusability after four successive runs.
关键词： Heterogeneous Fenton reaction,Organic dyes,Ag/Fe3O4/graphene
更新于2025-09-23 15:23:52