Iron-based Nanocomposites Research Articles

Pectin-nano zero valent iron nanocomposites for efficient heavy metal removal and bactericidal action against waterborne pathogens — Innovative green solution towards environmental sustainability

This study investigated the effectiveness of a pectin-nano zero-valent iron-based nanocomposite in adsorbing heavy metals in bimetallic form (chromium‑lead mixture), along with assessing its antibacterial properties. The nanocomposite was synthesized using a straightforward dispersion method, employing eco-friendly components like biocompatible pectin sourced from banana peels and nano-scale zero-valent iron. Analytical characterization confirmed the formation of stable, nano-crystalline particles with active interactions between the functional groups of pectin and nano iron. Batch adsorption experiments optimized various parameters such as pH, adsorbent dosage, contact time, metal ion concentration, and temperature to enhance bimetal removal from water. The optimal conditions were determined as pH 8.0, a temperature of 40 °C, 1.0 g/L adsorbent dosage, 75 mg/l initial bimetal concentration, and a contact time of 30 min. Further assessments revealed that the nanocomposite did not induce phytotoxic or ecotoxic effects, confirming its non-toxicity and environmental safety. Biocompatibility studies conducted using zebrafish models showed no adverse effects on hatching, survival, or heart rate. These findings underscore the potential of the nanocomposite as a sustainable and efficient solution for heavy metal remediation in water treatment process.

Reverse loading of inert Al2O3 onto active iron oxide for improved H2O2 activation and pollutant degradation

Developing heterogeneous iron-based catalysts with superior reactivity and stability is a long-term goal for hydrogen peroxide (H2O2) activation in Fenton-like technique for water remediation. Supported iron-based nanocomposites are of great interest due to their earth abundance, environmental friendliness, and tunable structure. However, existing iron-based Fenton catalysts are normally designed via the loading of iron-derived nanoparticles onto various inert substrates, where the surface reactive sites are hardly affected by the substrate. Here, we report the first example of reversely loaded FeOx-Al2O3 nanocomposite via overturning the loading direction, i.e., loading inert Al2O3 support onto reactive FeOx nanoparticles. The resultant FeOx@Al2O3-R catalyst demonstrated much improved reactivity for H2O2 activation and bisphenol A removal (by 14 times in terms of first-order rate constant) than its analog FeOx/Al2O3-T, which was prepared via the loading of FeOx nanoparticles onto inert Al2O3 support. Moreover, FeOx@Al2O3-R exhibited excellent stability with Fe leaching only one sixth of FeOx/Al2O3-T. Systematic characterization results revealed that the inert Al ions modify the electronic environment and properties of the surface Fe reactive sites. This work provides an alternative reverse loading strategy to traditional loading method for the preparation of iron-based nanocomposite catalyst that is highly efficient for H2O2 activation and pollutant removal.

An Acid-Responsive Iron-Based Nanocomposite for OSCC Treatment

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, characterized by invasiveness, local lymph node metastasis, and poor prognosis. Traditional treatment and medications have limitations, making the specific inhibition of OSCC growth, invasion, and metastasis a challenge. The tumor microenvironment exhibits mildly acidity and high concentrations of H2O2, and its exploitation for cancer treatment has been widely researched across various cancers, but research in the oral cancer field is relatively limited. In this study, by loading ultra-small Prussian blue nanoparticles (USPBNPs) into mesoporous calcium–silicate nanoparticles (MCSNs), we developed an acid-responsive iron-based nanocomposite, USPBNPs@MCSNs (UPM), for the OSCC treatment. UPM demonstrated excellent dual enzyme activities, generating toxic ·OH in a mildly acidic environment, effectively killing OSCC cells and producing O2 in a neutral environment to alleviate tissue hypoxia. The results showed that UPM could effectively inhibit the proliferation, migration, and invasion of OSCC cells, as well as the growth of mice solid tumors, without obvious systemic toxicity. The mechanisms may involve UPM inducing ferroptosis of OSCC cells by downregulating the xCT/GPX4/glutathione (GSH) axis, characterized by intracellular iron accumulation, reactive oxygen species accumulation, GSH depletion, lipid peroxidation, and abnormal changes in mitochondrial morphology. Therefore, this study provides empirical support for ferroptosis as an emerging therapeutic target for OSCC and offers a valuable insight for future OSCC treatment.

A lignin–derived N-doped carbon-supported iron-based nanocomposite as high-efficiency oxygen reduction reaction electrocatalyst

Fuel cells are a promising renewable energy technology that depend heavily on noble metal Pt-based catalysts, particularly for the oxygen reduction reaction (ORR). The discovery of new, efficient non-precious metal ORR catalysts is critical for the continued development of cost-effective, high-performance fuel cells. The synthesized carbon material showed excellent electrocatalytic activity for the ORR, with half-wave potential (E1/2) and limiting current density (JL) of 0.88 V and 5.10 mA·cm−2 in alkaline electrolyte, respectively. The material has a Tafel slope of (65 mV dec−1), which is close to commercial Pt/C catalysts (60 mV dec−1). Moreover, the prepared materials exhibited excellent performance when assembled as cathodes for zinc-air batteries. The power density reached 110.02 mW cm−2 and the theoretical specific capacity was 801.21 mAh g−1, which was higher than that of the Pt/C catalyst (751.19 mAh g−1). In this study, with the assistance of Mg5(CO3)4(OH)2·4H2O, we introduce an innovative approach to synthesize advanced carbon materials, achieving precise control over the material's structure and properties. This research bridges a crucial gap in material science, with potential applications in renewable energy technologies, particularly in enhancing catalysts for fuel cells.

Polyporus umbellatus polysaccharide iron-based nanocomposite for synergistic M1 polarization of TAMs and combinational anti-breast cancer therapy

M1 polarization of tumor-associated macrophages (TAMs) is a promising approach to breaking through therapeutic barriers imposed by the immunosuppressive tumor microenvironment (TME). As a clinically-used immunopotentiator for cancer patients after chemotherapies; however, the immunomodulatory mechanism and potential of polyporus polysaccharide (PPS) remains unclear. Here, we present mannose-decorated PPS-loaded superparamagnetic iron-based nanocomposites (Man/PPS-SPIONs) for synergistic M1 polarization of TAMs and consequent combinational anti-breast cancer therapy. Once internalized by M2-like TAMs, PPS released from Man/PPS-SPIONs induces the M1 polarization via IFN-γ secretion and downstream NF-κB pathway activating. The SPIONs within the nanocomposites mediate a Fenton reaction, producing OH· and activating the subsequent NF-κB/MAPK pathway, further facilitating the M1 polarization. The Man/PPS-SPIONs thereby establish a positive feedback loop of M1 polarization driven by the “IFN-γ-Fenton-NF-κB/MAPK” multi-pathway, leading to a series of anti-tumoral immunologic responses in the TME and holding promising potential in combinational anticancer therapies. Our study offers a new strategy to amplify TME engineering by combinational natural carbohydrate polymers and iron-based materials.

Novel iron-based nanocomposites for arsenic removal in groundwater: insights from their synthesis to implementation for real groundwater remediation

Novel iron-based nanocomposites for arsenic removal in groundwater: insights from their synthesis to implementation for real groundwater remediation

Iron-based nanocomposites implanting in N, P Co-doped carbon nanosheets as efficient oxygen reduction electrocatalysts for Zn-Air batteries

Reasonable design and construction of efficient and cost-effective oxygen reduction reaction (ORR) electrocatalysts are vital for promoting the practical application of zinc-air batteries (ZABs). Herein, we reported a one-pot self-assemble approach in combination with pyrolysis to prepare nanocomposite electrocatalyst comprised of atomically dispersed Fe-Nx sites and uniformly implanted FeP nanoparticles, which supported on N, P co-doped porous carbon nanosheets (denoted as 2D-FeP@FeNC-900). The 2D-FeP@FeNC-900 exhibits large specific surface area and hierarchical porous structure, along with unique incorporation of FeP, Fe-Nx and N, P co-doping provides abundant active sites and favorable synergistic effect, imparting 2D-FeP@FeNC-900 superior kinetic and electrocatalytic activity towards ORR. Meanwhile, the 2D-FeP@FeNC-900 displays an advantage of methanol-resistance over benchmark Pt/C catalyst. Moreover, the ZABs with 2D-FeP@FeNC-900 achieve superior discharge power density of 260 mW cm−2, specific capacitance of 803.7 mA h g−1, and excellent cyclic stability (when combined with RuO2) of over 130 h, surpassing those of Pt/C counterpart. This work provides an effective and generalizable strategy for engineering metal-compound and atomic-sites on dual-doped nanocarbon matrix for sustainable energy conversation and storage devices.

MOF-derived N-doped carbon composites embedded with Fe/Fe3C nanoparticles as highly chemoselective and stable catalysts for catalytic transfer hydrogenation of nitroarenes

Owing to the competitive hydrogenation of reducible functionalized groups and the complexity of the reaction mechanism, the selective catalytic hydrogenation of nitroarene compounds to value-added amine products is challenging. Herein, we designed and prepared a series of highly efficient iron-based nanocomposites (Fe/Fe3C@NC–T) via direct pyrolysis of the presynthesized NH2–MIL–101(Fe) octahedrons under nitrogen atmosphere, wherein tiny metallic Fe/Fe3C nanoparticles (NPs) were homogeneously inlaid in the N-doped porous carbon matrix. Among the various derived catalysts, Fe/Fe3C@NC–750 exhibited the best performance, with good tolerance to several different functional groups for the catalytic transfer hydrogenation of nitroarenes to anilines using N2H4·H2O as the reductant under mild conditions. This performance was also superior to those of commercial catalysts (Fe, Fe2O3, and Fe3C) and Fe/Fe3C@C–750 without N doping. The synergistic catalysis between the Fe-based NP and N dopant mainly contributed to the excellent catalytic performance of Fe/Fe3C@NC–750. Moreover, the mechanism study revealed that both the direct route and the condensation route were involved in this catalytic reaction system.

Experimental observation of third-order effect in magnetic small-angle neutron scattering

A recent theory [Metlov and Michels, Phys. Rev. B 91, 054404 (2015)] predicts a qualitatively new effect in the magnetic small-angle neutron scattering (SANS) cross section of statistically-isotropic disordered ferromagnetic media. The effect is due to the third-order terms in the amplitude of the inhomogeneities. Here, its existence is demonstrated both numerically via large-scale micromagnetic simulations and analyzed experimentally in a two-phase iron-based nanocomposite. The previous model is extended to an arbitrary spatial defect profile, which allows us to describe the experimental field dependence of the third-order SANS effect quantitatively.

Electrical, dielectric and photocatalytic applications of iron-based nanocomposites

A series of iron-based nanocomposites such as Cu–Fe (CFNCs), Ni–Fe (NFNCs), Ag–Fe (SFNCs) and Al–Fe (AFNCs) were fabricated via sol–gel route. An extensive investigation about crystallinity, microstructure, electrical and optical properties was carried out by utilizing X-ray diffractometer (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM). The frequency-dependent AC conductivity, dielectric constant and dielectric loss were measured in the frequency range of 25 kHz–2 MHz at room temperature via an LCR meter. The highest conductivity ~ 2.85 × 10−7S/m was revealed by AFNCs as compared to other nanocomposites. The Maxwell–Wagner model for induced polarization and Koop’s phenomenological theory of dielectrics were followed by all the fabricated nanocomposites in the temperature range of 30–600 °C. The maximum dielectric constant ~ 930 was measured for AFNCs at a temperature of 200 °C. Furthermore, the synthesized nanocomposites effectively degraded a toxic organic dye Rhodamine B (RhB) and the degradation (%) ~ 77, 85, 86, and 87 within the time of 50, 40, 50 and 70 min was recorded for CFNCs, NFNCs, SFNCs and AFNCs, respectively.

N-doped porous carbon hollow microspheres encapsulated with iron-based nanocomposites as advanced bifunctional catalysts for rechargeable Zn-air battery

The design and development of low-cost, efficient, and stable bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are desirable for rechargeable metal-air batteries. In this work, N-doped porous hollow carbon spheres encapsulated with ultrafine Fe/Fe 3 O 4 nanoparticles (FeO x @N-PHCS) were fabricated by impregnation and subsequent pyrolysis, using melamine-formaldehyde resin spheres as self-sacrifice templates and polydopamine as N and C sources. The sufficient adsorption of Fe 3+ on the polydopamine endowed the formation of Fe-N x species upon high-temperature carbonization. The prepared FeO x @N-PHCS has advanced features of large specific surface area, porous hollow structure, high content of N dopants, sufficient Fe-N x species and ultrafine FeO x nanoparticles. These features endow FeO x @N-PHCS with enhanced mass transfer and considerable active sites, leading to high activity and stability in catalyzing ORR and OER in alkaline electrolyte. Furthermore, the rechargeable Zn-air battery with FeO x @N-PHCS as air cathode catalyst exhibits a large peak power density, narrow charge-discharge potential gap and robust cycling stability, demonstrating the potential of the fabricated FeO x @N-PHCS as a promising electrode material for metal-air batteries. This new finding may open an avenue for rational design of bifunctional catalysts by integrating different active components within all-in-one catalyst for different electrochemical reactions. N-doped porous hollow microspheres with encapsulated Fe-based nanocomposite show impressive activity and stability for ORR and OER, capable of serving as efficient cathode catalysts for the rechargeable Zn-air batteries.

Oral Submucous Fibrosis as an Overhealing Wound: Implications in Malignant Transformation.

Oral submucous fibrosis is an oral potentially malignant disorder with high incidence of malignant transformation and rising global prevalence. However, the genesis of oral submucous fibrosis is still unclear despite superfluity of literature. In the background of ineffective treatment, it is necessary to decode its onset and progression before designing customized treatment regimens. The objective of this article is to decipher the pathogenesis of oral submucous fibrosis in order to identify novel drug targets. A thorough literature review based on oral submucous fibrosis being an overhealing wound was conducted; several related patents were identified and herewith reviewed. Necessary pathways were elaborated and deliberated in the manuscript in the form of schemas, keeping our hypothesis in mind. Several novel molecular targets were identified and discussed in detail. Several patents demonstrating inhibition of fibrosis via chemokine ligand mimetics, anticonnexon antibodies, stem cell therapy, fibronectin blocking peptides, HIF inhibitors, recombinant erythropoietin, xanthine oxidase inhibitors, long non-coding RNAs, targeting inflammation, increasing TH-1/TH-2 cytokine ratio, t-box protein 4, chromium containing compositions, Iron-based nanocomposites, Lactate Dehydrogenase-5 inhibitors, Carbonic Anhdrase-9 inhibitors, proton pump inhibitors, liposomal encapsulated glutathione, monocarboxylate-4 inhibitors, autophagy inhibitors, Submucosal anti-IL-6 antibodies, fibrin degradation products for monitoring of malignancy and fibrosis, small molecule antagonists like vorapaxar, tiplaxtinin, and TM-5275, TGF-β signalling inhibitors were identified as future therapeutic avenues. Considering, oral submucous fibrosis as an overhealing wound explains both pathogenesis and malignant transformation. Certainly, abnormalities in coagulation and fibrinolytic system are a common denominator in the profibrotic milieu and associated malignancy.

Novel porous FexCyNz/N-doped CNT nanocomposites with excellent bifunctions for catalyzing oxygen reduction reaction and absorbing electromagnetic wave

In this work, a novel porous iron-based nanocomposite containing Fe3C, Fe3N, Fe (FexCyNz) and nitrogen doped carbon nanotubes (N-CNT) was designed and prepared. The typical product (FexCyNz/N-CNT-1000) possesses a unique characteristic of mesoporous structure with high BET surface area (401.5 m2 g−1) and outstanding electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline solution, such as high limiting currents, superior methanol tolerance, relatively high stability and a near four-electron ORR pathway. More importantly, the onset potential of the representative sample is pretty close to that of commercial Pt/C. Surprisingly, the FexCyNz/N-CNT-1000 exhibits excellent electromagnetic (EM) wave absorption property, especially in the frequency range of C-band. The composite filled with 12% of FexCyNz/N-CNT-1000 sample in paraffin displays a maximum reflection loss (RL) of −25.1 dB at 4.5 GHz with a thickness of 4.0 mm, meanwhile, the absorption bandwidths below -10 dB (90% absorption) were 8.2 GHz with the variation thickness ranging from 2.0 to 5.0 mm. Consequently, we believe the present study provides a good reference for synthesizing novel multifunctional nanomaterials.

Carbon-Bound Iron Oxide Nanoparticles Prevent Calcium-Induced Iron Deficiency in Oryza sativa L. .

Iron-based nanocomposites can be a practical solution to combat iron deficiency in calcareous agricultural soil. In the present study, a carbon-bound iron oxide nanoparticle is synthesized by mixing ferric chloride and caffeic acid and tested to correct Ca-inducible Fe deficiency in rice. Physicochemical characterization points that the nanoparticle is carbon-coated semi-crystalline Fe3O4. It is found that nanoparticle amendment enhances bioproductivity, photosynthetic electron transport, antioxidant enzyme activity, and Fe accumulation under Ca stress. Reduction in Ca accumulation via physical adsorption, Fe release from the particles, and maintenance of molecular responses related to Fe acquisition were the reasons for the above progressive growth effects. Thus, it is concluded that nanoparticles synthesized in the study act as a potential ameliorant to correct Ca-induced Fe deficiency in rice plants.

The role of polyaniline in the formation of iron-containing nanocomposites

Polyaniline (PANI)-coated iron-based nanocomposites with a range of magnetisation and coercivity values were produced by in situ polymerisation of aniline and chemical reduction of Fe3+ by BH4 −. We have varied the ratio of aniline to iron, keeping the amount of BH4 − added constant, and vice versa. Room-temperature magnetisation loops, X-ray diffraction patterns, Mossbauer spectra and transmission electron microscopy images show that PANI plays two distinct roles: on the one hand, it coats the iron particle surface, preventing oxidation of the Fe cores and, on the other, it enhances the formation of an Fe100−x B x alloy. The incorporation of boron in the alloy is facilitated by the polymer entrapment of small Fe nuclei. The mean particle size determined for composites obtained with low PANI content is (50 ± 20) nm, while for PANI-rich composites (30 ± 10) nm particles are formed.

Spin disorder induced reentrant ferromagnetism in iron-based nanocomposites

The low-temperature magnetic behavior of pure iron nanocrystallites dispersed in MgO matrix has been investigated by dc magnetization and ac susceptibility measurements. Irreversibilities in the magnetization data at low field are observed at low temperatures, indicating a passage from a high temperature ferromagnetic phase to a low-temperature disordered, frozen state. Quenching of these irreversibilities is seen when the external magnetic field is increased. The variation of the in-phase susceptibility with temperature showed marked frequency dependence whereas the out-of-phase susceptibility component passes through a maximum. The origin of this behavior is traced to the spin disorder at the grain boundaries, which exhibit a co-operative freezing below a certain temperature.

α-Fe nanopowder synthesised in low-pressure microwave plasma and studied by Mössbauer spectroscopy

An iron-based nanocomposite has been prepared by the microwave plasma method: Fe(CO)5 vapour was introduced into an argon discharge at ∼1 kPa. The synthesised nanopowder was passivated in situ with a mixture of Ar and air. The as-prepared nanopowder was characterised by XRD, TEM, Raman and Mössbauer spectroscopies. In the XRD pattern of the nanopowder the α-Fe (dXRD = 14 nm, 76 wt.%) and Fe3O4 (dXRD = 3 nm, 24 wt.%) phases were identified only. α-Fe cores covered with oxide shells were observed under TEM. A huge increase of Mössbauer absorption was observed after the sample was cooled down to 5 K. The results of magnetic and thermal properties studies at low and high temperature are presented. The heat capacity of the sample exhibited an unexpectedly high value of 599 J/kg/K.

Evaluating the effect of SiC content on iron-based nanocomposite

Iron has wide application in manufacturing industries and the objective of this study is to investigate the effect of silicon carbide (SiC) particles on iron-based nanocomposites. SiC is effectively reinforced into iron matrix by mechanical alloying process using high-energy ball mill. The Fe–SiC nanocomposites with various compositions of SiC viz., 15%, 20% and 25% are characterised using X-ray diffraction and atomic force microscopy. The nanocomposite powders are compacted and sintered into pellets. Their elastic properties, hardness and Poisson's ratio are determined using the pulse echo technique. Moreover, the densities of the pellets are measured using Archimedes’ principle by the water immersion method.

Catalyzed growth of oriented carbon nanotubes using Fe–organosilicon core–shell nanoparticles

Iron-based nanocomposites were synthesized by the CO 2 laser-induced co-pyrolysis of Fe(CO) 5 and [(CH 3) 3Si] 2O (HMDSO) vapors. The obtained nanoparticles exhibited an iron-based core surrounded by an organosilicon polymer shell. Particles having different thicknesses of the polymer shell were deposited by either a spin-coating or by a drop-casting method on Si(1 0 0) substrates. Carbon nanotubes (CNTs) were grown by dc plasma-assisted and filaments-activated CCVD processes in H 2/C 2H 2 mixtures at 700 °C. The CNT growth was studied by several analytical techniques: SEM, TEM and Raman spectroscopy. High density of well-aligned, vertical MWCNTs was obtained.

Iron-Based Nanocomposite Synthesised by Microwave Plasma Decomposition of Iron Pentacarbonyl

A nanocrystalline iron-based powder has been prepared by microwave plasma method: Fe(CO)5 vapor was introduced into an argon discharge at ~1 kPa. A microwave 2.45 GHz generator was operated at 430 W. The reaction took place inside a quartz tube passing through a microwave waveguide. The microwave discharge (without and with Fe(CO)5) was characterized by optical emission spectroscopy. The synthesized nanopowder was passivated in situ with air. The asprepared nanopowder was characterized by TEM, XRD, Raman and Mössbauer spectroscopies. The nanopowder included α-Fe, α-Fe2O3, and Fe3O4 phases. The core-shell nanoparticles were observed under TEM: α-Fe cores had shells formed of Fe3O4 or carbon. The mean crystallite size of α-Fe was 36 nm (Scherrer formula). The synthesized nanopowder exhibited ferromagnetic behavior.