Fe3O4 Magnetic Nanoparticles Research Articles

Preparation and characterization of Fe3O4 magnetic nanoparticles and study of its synergistic effect with ethoxylated tallow amine on oil demulsification efficiency

Preparation and characterization of Fe3O4 magnetic nanoparticles and study of its synergistic effect with ethoxylated tallow amine on oil demulsification efficiency

Effect of Synthesizing Process on the Formation of Fe3O4 Magnetic Nanoparticles

In this work, the effect of synthesizing process on the morphology, structure, and magnetic properties of Fe3O4 magnetic nanoparticles have been studied by performing X-ray diffraction, scanning electronic microscopy, and vibrating sample magnetometer measurements. Fe3O4 nanoparticles were synthesized by hydrothermal and solvothermal methods. X-ray diffraction analysis revealed that both samples have cubic crystal phase. However, Fe2O3 impurity peaks were observed in the sample synthesized by hydrothermal method. The crystallite sizes of samples synthesized by hydrothermal and solvothermal methods were approximately 38 and 24 nm, respectively. The scanning electron microscope images show that spherical porous and cubic shape Fe3O4 nanoparticles were obtained by solvothermal and hydrothermal method, respectively. The average particle sizes of Fe3O4 samples synthesized by hydrothermal and solvothermal methods were determined as 220 and 450 nm, respectively. Both samples behave a soft ferromagnetic characteristic having almost zero coercive field. The magnetic saturation values of Fe3O4 nanoparticles synthesized by hydrothermal and solvothermal methods were determined as 28.78 and 77.31 emu/g, respectively. As a result of the characterizations, porous Fe3O4 nanoparticles synthesized by solvothermal method show better crystal structure, morphological and magnetic properties than Fe3O4 nanoparticles synthesized by hydrothermal method.

Fe3O4 Magnetic Nanoparticles Obtained by the Novel Aerosol-Based Technique for Theranostic Applications.

This work is aimed at presenting a novel aerosol-based technique for the synthesis of magnetite nanoparticles (Fe3O4 NPs) and to assess the potential medical application of their dispersions after being coated with TEA-oleate. Refinement of the processing conditions led to the formation of monodispersed NPs with average sizes of ∼5-6 nm and narrow size distribution (FWHM of ∼3 nm). The NPs were coated with Triethanolammonium oleate (TEA-oleate) to stabilize them in water dispersion. This allowed obtaining the dispersion, which does not sediment for months, although TEM and DLS studies have shown the formation of small agglomerates of NPs. The different behaviors of cancer and normal cell lines in contact with NPs indicated the diverse mechanisms of their interactions with Fe3O4 NPs. Furthermore, the studies allowed assessment of the prospective theranostic application of magnetite NPs obtained using the aerosol-based technique, particularly magnetic hyperthermia and magnetic resonance imaging (MRI).

Synthesis of a porous hollow magnetic molecularly imprinted microsphere by O/W/O composite emulsion polymerization for specifically recognizing bovine serum albumin

Molecular imprinting technology is highly successful for low-molecular-weight molecules, but is still confronted with many challenges for proteins. This study introduces a strategy to synthesize hollow magnetic molecularly imprinted microspheres (HMMIMs) under Fe3O4 magnetic nanoparticles matrix, by oil-in-water-in-oil composite emulsion polymerization with alkylphenol ethoxylates and Span-80 as emulsifiers. The synthesis conditions after optimization were 1.0 mmol thermo-sensitive functional monomer N-isopropylacrylamide, 1.0 mmol cross-linker N, N-methylene bisacrylamide, 2.0 wt% vinyl-modified silk fibroin, and 50 mg Fe3O4@COOH nanoparticles. The morphology structure and the forming process of the acquired HMMIMs were well characterized by POM, SEM, TEM and FT-IR. The HMMIMs were synthesized successfully with a porous structure and large specific surface area. The particle size of the obtained HMMIMs was at 10–20 µm. The obtained microspheres were superparamagnetic and thermo-responsive. The HMMIM adsorption capacity at 25 °C toward bovine serum albumin (BSA) was 89.9 mg/g and the BSA separation factor in BSA/BHb mixtures was 2.12. A good separation efficacy toward BSA was also observed in bovine whole blood. The prepared HMMIM possessed heterogeneous active sites, the BSA adsorption process on HMMIM was chemisorption controlled.

Biosynthetic amyloid fibril CsgA-Fe3O4 composites for sustainable removal of heavy metals from water

Removal of heavy metals from water has been a hot topic. However, few studies have been conducted for the tricky low concentration range. Experimental designs often have heavy metal concentrations much higher than the actual environmental loading, which leads to poor practical results of adsorbent materials. This study showed that amyloid fiber CsgA-Fe3O4 composites are ideal for the removal of heavy metals from water, especially at low concentrations. We constructed CsgA-Fe3O4 composites by fusing short functional peptides that specifically bind to Fe3O4 magnetic nanoparticles. The CsgA-Fe3O4 composites achieved 98.73 %, 98.43 %, and 93.00 % removal of 1 mg/L Cu2+, Cd2+, and Pb2+, respectively. Moreover, the adsorption rate remained above 80 % after six repeated adsorptions, indicating that CsgA-Fe3O4 was highly reusable. Meanwhile, the high removal rate (>90 %) of heavy metals in the simulated wastewater demonstrated the excellent environmental stability of CsgA-Fe3O4. Finally, by FT-IR and XPS characterization, we found that the adsorption mechanism of CsgA-Fe3O4 is mainly the complexation of surface oxygen-containing functional groups and heavy metal ions. In general, the CsgA-Fe3O4 composite is an efficient, inexpensive, and sustainable adsorption material for mitigating low concentrations of difficult-to-treat heavy metal pollution in water bodies.

Synthesis of pectin hydrogel /Fe3O4/Bentonite and its use for the adsorption of Pb (II), Cu (II), and Cd (II) heavy metals from aqueous solutions

The magnetic nano adsorbent was prepared by adding Fe3O4 magnetic nanoparticles and bentonite clay into the three-dimensional (3D) cross-linked pectin hydrogel substrate. To determine optimum adsorption conditions, effective factors on the adsorption efficiency of the Pb (II), Cu (II), and Cd (II), including solution pH, adsorbent dosage, contact time, and initial concentration of pollutants, have been experimentally investigated. Thus, in optimum conditions, i.e., contact time (60 min), pH 7, adsorbent dosage (0.03 g), and initial concentration (100 mg/L), the adsorption efficiency of Pb (II), Cu (II), and Cd (II) was obtained at 95.2 %, 92.8 %, and 87.6 %, respectively. The results of the adsorption isotherm studies exhibit a good fit of the data with the Langmuir adsorption isotherm. The obtained kinetic and thermodynamics parameters illustrated that the pseudo-second-order equations, the spontaneous process and endothermic, control the adsorption process.

Origin of Enhancement of Orbital Magnetic Moment in SiO2-Coated Fe3O4 Nanocomposites Studied by X-ray Magnetic Circular Dichroism.

In this study, magnetic Fe3O4 nanoparticles (NPs) were dispersed uniformly by varying the thickness of the SiO2 coating, and their electronic and magnetic properties were investigated. X-ray diffraction confirmed the structural configuration of monophase inverse-spinel Fe3O4 NPs in nanometer size. Scanning electron microscopy revealed the formation of proper nonporous crystallite particles with a clear core-shell structure with silica on the surface of Fe3O4 NPs. The absorption mechanism studied through the zeta potential indicates that SiO2-coated Fe3O4 nanocomposites (SiO2@Fe3O4 NCs) possess electrostatic interactions to control their agglomeration in stabilizing suspensions by providing a protective shield of amorphous SiO2 on the oxide surface. High-resolution transmission electron microscopy images demonstrate a spherical morphology having an average grain diameter of ∼11-17 nm with increasing thickness of SiO2 coating with the addition of a quantitative presence and proportion of elements determined through elemental mapping and electron energy loss spectroscopy studies. Synchrotron-based element-specific soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) techniques have been involved in the bulk-sensitive total fluorescence yield mode to understand the origin of magnetization in SiO2@Fe3O4 NCs. The magnetization hysteresis of Fe3O4 was determined by XMCD. At room temperature, the magnetic coercivity (Hc) is as high as 1 T, which is about 2 times more than the value of the thin film and about 5 times more pronounced than that of NPs. For noninteracting single-domain NPs with the Hc spread from 1 to 3 T, the Stoner-Wohlfarth model provided an intriguing explanation for the hysteresis curve. These curves determine the different components of Fe oxides present in the samples that derive the remnant magnetization involved in each oxidation state of Fe and clarify which Fe component is responsible for the resultant magnetism and magnetocrystalline anisotropy based on noninteracting single-domain particles.

Polycarbonate-coated magnetic nanoparticles for the extraction of imipramine and its primary metabolite from urine.

This study introduces a reliable and inexpensive magnetic dispersive solid phase extraction to extract imipramine and its primary metabolite (desipramine) from urine samples. To accomplish this aim, Fe3 O4 magnetic nanoparticles were synthesized by sonication, subsequently, polycarbonate was precipitated gradually onto the surface of them to form the adsorbent. Extraction recoveries of 85% and 76%, enrichment factors of 57 and 51, limits of detection of 2.5 and 2.8μg/L, and limits of quantification of 8.3 and 9.3μg/L were obtained for imipramine and desipramine under the optimal conditions, respectively. In addition, relative standard deviations for intra- (n=6) and inter-day (n=5) precisions at two concentrations (50 and 100μg/L of each analyte) were less than or equal to 4%. Short extraction time, good repeatability, high enrichment factors, and simplicity are the main advantages of the proposed method.

Preparation of diester-based ferrofluid and applied research in sealing

To improve the sealing performance of ferrofluid, a Fe3O4 magnetic nanoparticles with different coating times was synthesized by the chemical co-precipitation method, and the performance of diester-based Fe3O4 ferrofluid was investigated and characterized. A convergent ferrofluid seal (CFFS) device was designed and the prepared ferrofluid was applied to it. The influence of important factors such as seal clearance and pole teeth of CFFS on the pressure capability of the CFFS are investigated using simulations and experiments. The results show that the prepared magnetization intensity of the ferrofluid is 29.5 kA/m. The simulation and experimental results of the CFFS agree well, and its performance is 3.3 times that of the ordinary ferrofluid seal.

Oil content removal from oil water emulsion by super magnetic nanoparticles

Oily wastewater treatment processes are facing challenges due to strict regulations in the quality of effluent standards and waste production. The reuse of oily wastewater treatment effluents is rapidly gaining attention for achieving sustainable water supply. Fe3O4 magnetic nanoparticles (MNPs) are widely applied as super adsorbents in industry. In the present study, the MNP was sprayed and mixed with oil-water emulsion, after the application of a magnetic field, a clear effluent was seen within minutes. The effects of the varying process parameters including, adsorbent dose, particle size, mixing time, American Petroleum Institute gravity (API gravity), pH, temperature, and oil concentration, on the percentage of oil removal and the removal capacity (mg/g) were studied. In this paper, six types of Fe3O4 magnetic nanoparticles (A:50 nm, B:15–20 nm, C:3 nm) and functionalized NH2/-COOH (A1:20–30 nm, B1:15–20 nm and C1:3 nm) were used as oil adsorbent. The highest percentage of oil removal was reached at 20 min, using 150 mg/L oil concentration, 100 mg adsorbent dose, room temperature, 28 API, and at 4 pH, and the results were 60 % (A), 72 % (B), 81 % (C), 85 % (A1), 88 % (B1) and 94 % (C1). Functionalized Fe3O4 nanoparticles exhibited higher reusability than uncoated MNPs (A-C). The results showed that Fe3O4 were highly effective, reusable, and suitable for oil removal from the oil-water emulsion. Kinetic models fit effectively with pseudo-second-order mode, and Freundlich model. This work also matches the research conducted by various researchers for oil removal from oily water using magnetic nanoparticles.

Feasibility of magnetite-poly(n-isopropylacrilamide) smart nanocarriers containing doxorubicin for cancer therapeutic applications

The current study introduces a novel smart magnetic nanocarrier based on poly (n-isopropylacrilamide). Initially, magnetic nanoparticles were synthesized via the co-precipitation method and revealed an average size of 72 ± 10 nm. XRD confirmed the magnetite structure, and VSM showed a saturation magnetization of 69.63 emu/g for the synthesized Fe3O4 magnetic nanoparticles. The optimized nanoparticle was then encapsulated within poly (n-isopropylacrylamide) at 5, 10, and 15 wt%, using an electro-spraying system. A range of techniques were applied to fully characterize the resultant smart magnetic nanocarriers. The FTIR results confirmed the successful loading of doxorubicin drug. Results revealed a faster drug release at higher temperatures, and at an acidic pH (37 °C and pH = 5.1). According to the release profile, 26.6% of the drug release had occurred in an acidic environment, while about 23.2% was detected at pH = 7.1. The presence of Fe3O4 nanoparticles allowed for a more controlled drug release. In vitro studies using MG63 cell line demonstrated non-cytotoxic results for the polymeric nanocarriers, and revealed a reduced cell viability in the presence of doxorubicin, confirming the effectiveness of the nanocarrier. Overall, the results demonstrate the feasibility of the optimized nanocarrier system for cancer therapeutic applications, and highlight its potential for simultaneous chemotherapy and hyperthermia.

Magnetic‐optical dual functional Janus particles for the detection of metal ions assisted by machine learning

AbstractFunctional polymer microspheres have broad application prospects in various fields, such as metal ion detection, adsorption, separation, and controlled drug release. However, integrating different functions in a single microsphere system is a significant challenge in this field. In this work, we prepared multicompartmental emulsion droplets utilizing microfluidic technology. Fe3O4 magnetic nanoparticles were added to one of the compartments of the emulsion droplets as functional particles, and Janus microspheres were obtained after curing. Fluorescent probes enter the two compartments of the Janus microspheres by diffusion. The fluorescence changes of the microspheres were observed in situ and captured through a fluorescence microscope. The images are processed by image recognition software and a Python program. The “fingerprint” of the detected metal ions is obtained by dimensionality reduction of the data through Principal Component Analysis. We employ different algorithms to build Machine Learning models for predicting the metal ion species and concentration. The variation of fluorescence intensity of the three fluorescent probes and the corresponding R, G, and B channel values and time are used as descriptors. The results show that the Random Forest, K‐neighborhood (KNN), and Neural Network models demonstrated a better predicted effect with a variance (R2) greater than 0.9 and a smaller root mean square error; among them, the KNN model predicted the most accurate results.

Swarming Multifunctional Heater-Thermometer Nanorobots for Precise Feedback Hyperthermia Delivery.

Micro-/nanorobots (MNRs) are envisioned to act as "motile-targeting" platforms for biomedical tasks due to their ability to propel and navigate in challenging, hard-to-reach biological environments. However, it remains a great challenge for current swarming MNRs to accurately report and regulate therapeutic doses during disease treatment. Here we present the development of swarming multifunctional heater-thermometer nanorobots (HT-NRs) and their application in precise feedback photothermal hyperthermia delivery. The HT-NRs are designed as photothermal-responsive photonic nanochains consisting of magnetic Fe3O4 nanoparticles arranged periodically in one dimension and encapsulated in a temperature-responsive hydrogel shell. The HT-NRs exhibit energetic and controllable swarming motions under a rotating magnetic field, while simultaneously functioning as motile nanoheaters and nanothermometers, utilizing their photothermal conversion and (photo)thermal-responsive structural color changes (photothermochromism). Consequently, the HT-NRs can be quickly deployed to a remote target area (e.g., a superficial tumor lesion) using their collective motion and selectively eliminate diseased cells in a specific targeted region by utilizing their self-reporting photothermochromism as visual feedback for precisely regulating external light irradiation. This work may inspire the development of intelligent multifunctional theranostic micro-/nanorobots and their practical applications in precise disease treatment.

Synthesis, characterization and photovoltaic application of a new magnetic nanocomposite from polyaniline-Fe[formula omitted]O[formula omitted]-TiO[formula omitted

For many organic solar cells, the energy loss in separating closely coupled electron–hole pairs in low-mobility materials is high. In polymer solar cells (PSCs), photogenerated charge carrier recombination inside the PSCs and limited charge carrier mobility of disordered organic materials accounts for roughly 50% of the total efficiency loss. To solve these problems, in this work, we introduce magnetic Fe3O4 nanoparticles into the active layer of polymer solar cells. Specifically, an environmentally friendly and facile in situ method for the synthesis of a PANI-Fe3O4-TiO2 nanocomposite without the need for an organic solvent is described. The nanocomposite’s structural, thermal, morphological, optical, electrochemical and photovoltaic characteristics are studied. The TEM micrographs of the synthesized nanocomposite show the nanoplate structure of PANI, which is covered by Fe3O4 and TiO 2 nanoparticles. Because of the spin–orbit coupling effect of Fe3O4 on PANI, the band gap energy of the nanocomposite revealed an indirect electron transfer. The P–N heterojunction solar cell based on this nanocomposite, with a device structure of FTO/TiO2/PANI-Fe3O4-TiO2/Al, exhibited an improved power conversion efficiency (PCE) compared to the device without Fe3O4. Spin–orbit coupling and/or singlet fission induced by magnetic Fe3O4 nanoparticles is thought to effectively increase the number of triplet excitons, thereby suppressing the recombination process.

Fabrication of a bifunctional fluorescent chiral composite based on magnetic Fe3O4/chiral carbon dots@hierarchical porous metal-organic framework

Considering the selective pharmacological activity and ecotoxicity of chiral drugs, the development of chiral materials with the dual functions of enantiomeric recognition and adsorption is of great significance. Herein, a novel bifunctional chiral composite (Fe3O4/CCDs@HP-ZIF-8) which does not contain expensive and rare fluorescent chiral ligands or metal ions, was constructed for the first time by encapsulating chiral carbon dots (CCDs) and magnetic Fe3O4 nanoparticles into hierarchical porous metal-organic frameworks (HP-MOFs). Fe3O4/CCDs@HP-ZIF-8, which integrates fluorescent chiral property, magnetism, and hierarchical porosity, shows enormous potential in enantiomeric recognition and adsorption. Fluorescence detection results demonstrate that Fe3O4/CCDs@HP-ZIF-8 presents different fluorescence quenching for naproxen enantiomers. The limits of detection are determined to be 0.05 μM for S-naproxen (S-Nap) and 0.30 μM for R-naproxen (R-Nap), respectively. Furthermore, the isothermal, kinetic, and thermodynamic adsorption behaviors of Fe3O4/CCDs@HP-ZIF-8 to naproxen enantiomers were systematically studied. Due to its hierarchical porosity, the composite exhibits higher adsorption capacity to naproxen enantiomers compared to the non-hierarchical porous composite. Studies of enantiomeric recognition and adsorption mechanisms affirm that the synergistic effect of multiple mechanisms exists between Fe3O4/CCDs@HP-ZIF-8 and naproxen enantiomers. Finally, the satisfactory recoveries and relative standard deviations in the actual sample assays demonstrate the practicality of Fe3O4/CCDs@HP-ZIF-8 for S-Nap detection. This non-destructive functionalization method creates an innovative pathway for developing advanced multifunctional chiral materials, holding great promise for enantiomeric recognition and adsorption.

A new approach for the synthesis of α‐ketothioamides from methyl ketone, pyrrolidine/piperidine and elemental sulfur using recyclable magnetic catalyst

AbstractBACKGROUNDα‐Ketothioamides play a vital role in the fields of medicine and biology. There are many α‐ketothioamide synthesis pathways, but in general, most current methods involve either conventional heating in solvent conditions or using non‐recyclable catalysts. Thus, our work investigated the preparation of α‐ketothioamides under solvent‐free sonication using magnetic nanoparticle‐immobilized chlorozincate ionic liquid as a catalyst. The desired products were purified by chromatography columns and characterized using 1H NMR and 13C NMR.RESULTSIn this study, Lewis acidic ionic liquid grafted onto magnetic nanoparticles (Fe3O4@IL‐ZnCl2) was used as an effective heterogeneous catalyst for the generation of a variety of α‐ketothioamide derivatives. The optimized conditions were methyl ketone (1.0 mmol), amine (1.2 mmol), S8 (1.2 mmol) and Fe3O4@IL‐ZnCl2 (15 mg) under solvent‐free sonication at 80 °C for 5 h, and the crude products were obtained in a 34–94% isolated yield. Then, this procedure was successfully applied to a wide range of aryl and alkyl ketone compounds. Besides, there was only a slight loss in catalytic activity in three consecutive cycles, indicating the reusability and stability of the catalytic system.CONCLUSIONSWe have successfully designed a novel protocol for the generation of α‐ketothioamide derivatives from aryl/alkyl methyl ketones, amines, and elemental sulfur catalyzed by chlorozincate ionic liquid‐coated magnetic Fe3O4 nanoparticles. The reaction proceeded via a mild, efficient, solvent‐free sonication accompanied by a well‐reactive catalyst, which is easily separated and reusable. Besides, a feasible mechanism is presented. © 2023 Society of Chemical Industry.

Controlling the Physical Properties of Fe3O4-Immobilized Palladium Complexes towards Reusable Catalysts in the Methoxycarbonylation of 1-Hexene

This paper describes the use of immobilized palladium catalysts on Fe3O4 magnetic nanoparticles (MNPs) to afford magnetically separable catalysts in the methoxycarbonylation of 1-hexene. Immobilization of homogeneous complex [Pd(L1)Cl2] (Pd1), where L1 = N,N′E,N,N′E)-N,N′-(3-(3-(triethoxysilyl)propyl)pentane-2,4-diylidene)dianiline, on Fe3O4 MNPs at 100 °C and Pd loading of 10% (based on wt% of Pd1) afforded the corresponding complex [Pd1@Fe3O4] (Pd2) in good yields. The use of calcination temperatures of 150 °C and 200 °C produced compounds Pd3 and Pd4, respectively, while Pd metal loadings (based on wt% of Pd1) of 5% and 15% provided complexes Pd5 and Pd6, respectively. The immobilized compounds were analyzed using FT-IR spectroscopy, SEM-EDX, TEM, ICP-OES, and PXRD techniques. The surface areas and porosity of the materials were determined using nitrogen physisorption measurements and confirmed the formation of mesoporous materials, while SQUID measurements established Ms values in the range of 60.69 to 69.93 emu/g. The immobilized Pd(II) complexes catalyzed the methoxycarbonylation of 1-hexene, yielding mainly linear esters. The immobilized compounds could be recycled up to five times via magnetic separation without significant loss in catalytic activities.

Circular Economy Approach for Treatment of Water-Containing Diclofenac Using Recyclable Magnetic Fe3o4 Nanoparticles: A Case Study of Real Water Sample from Lake Victoria

Aims: A circular economy is a concept that aims to create a sustainable future by reducing waste and promoting the reuse of resources. In the field of water treatment, this concept has been applied through the use of recyclable materials to remove pollutants from water.
 Place and Duration of Study: In this study, we investigated the use of recyclable magnetic Fe3O4 nanoparticles to remove diclofenac from a water sample from Lake Victoria. The water sample was collected once to test the application of recyclable magnetic Fe3O4 nanoparticles in real environmental samples.
 Methodology: The nanoparticles were synthesized using a coprecipitation method and characterized using various techniques, including SEM/EDX, XRD, MPMS, ImageJ, and Solid addition method for PZC determination. The removal of diclofenac experiments was designed by response surface methodology.
 Results: The optimal conditions for diclofenac removal were pH 2, concentration 500 ug/L, contact time 60 minutes, and adsorbent dose 50 mg with a removal percentage of 69.95%. The reusability of the Fe3O4 nanoparticles was evaluated for three cycles, with removal percentages of 69.95%, 60%, and 41.6% for the first, second, and third cycles, respectively. This characteristic aligns with the principles of the circular economy, promoting resource conservation and waste reduction. The nanoparticles were also tested on a real water sample from Lake Victoria, resulting in 100% removal of diclofenac.
 Conclusion: This finding suggests that the Fe3O4 nanoparticles can be adopted for drinking water treatment in the East African community, addressing the issue of pharmaceutical contamination in water bodies.

3D spatially-confined magnetic anodes towards advanced lithium ion batteries

Magnetic transition-metal oxides show great prospect as alternatives to prevail anodic carbonaceous substances for lithium ion battery in virtue of their splendid theoretical capacity. However, in addition to their intrinsic poor electronic conductivity, the severe agglomeration of the forming magnetic metal nanoparticles during discharging will deteriorate their actual electrochemical performance in a strong magnetic field environment. Here, we demonstrate a 3D spatially-confining magnetic anode to settle all these dilemmas, in which conversion-type magnetic Fe3O4 nanoparticles with a thin carbon encapsulation layer are anchoring onto 3D nickel nanotube arrays skeleton (Ni/Fe3O4@C NTAs). The carbon shell spatially confines the agglomeration of Fe nanoparticles and maintains the exceptional integrity of structure. The Ni/Fe3O4@C NTAs anode exhibits high-capacity lithium storage (∼1286 mAh g−1 at 0.1 C) and superior rate/cycle capability (retaining ∼97 % of initial reversible value at 1 C after long-term 1000 cycles).

Broadband electromagnetic wave absorbing via PANI coated Fe3O4 decorated MoS2 hybrid nanocomposite

High performance electromagnetic wave (EMW) absorbing material systems are required for stealth applications and sensitive electronic devices. Absorbing of an incident EMW in a wide band range still has limitations in terms of materials system and engineering. It is required to extend the bandwidth and minimize the reflection from the material system for the next level stealth technologies. In this work, hybrid nanocomposite structures are developed by semiconductor flower-like MoS2 nanosheets, Fe3O4 magnetic nanoparticles and conductive polyaniline. A systematic study is presented by investigation the structural, magnetic, morphological, thermal, electronic and electromagnetic characteristic of hybrid nanocomposites (Fe3O4:MoS2, PANI@Fe3O4, PANI@MoS2 and PANI@Fe3O4:MoS2). EMW absorption characteristics results showed that Fe3O4:MoS2 and PANI@Fe3O4:MoS2 hybrid nanocomposites exhibit excellent EMW absorption characteristics. While the minimum reflection loss (RL) value was found as − 54.97 dB at 15.99 GHz for the Fe3O4:MoS2 nanocomposite, the broad bandwidth (7.65 GHz) was observed in PANI@Fe3O4:MoS2 hybrid nanocomposite having − 39.96 dB RL. According to the experimental results, a lightweight and high temperature resistance PANI@Fe3O4:MoS2 like-hybrid nanocomposite can absorb almost 90% of incident EMW in a wide bandwidth.