Synthesis and Properties of Nanosized Stoichiometric Cobalt Ferrite Spinel

Catalytic degradation of rhodamine blue and bactericidal action of AgBr and chitosan-doped CuFe2O4 nanostrucutres evidential molecular docking analysis

The harmful cationic dyes present in industrial waste significantly decrease the effectiveness of remedy operations. Considering the horrendous impact of these dyes on the environment and biodiversity, silver bromide (AgBr) and chitosan (CS) doped copper ferrite (CuFe2O4) nanostructures (NSs) were prepared by the co-precipitation route. In this work, The surface characteristics of CuFe2O4 can be altered by CS, potentially enhancing its catalytic reaction compatibility. The functional groups in CS interact with the surface of CuFe2O4, influencing its catalytic behavior. AgBr can have an impact on the dynamics of charge carriers in the composite. Better charge separation and transfer which is essential for catalytic processes. The catalytic degradation of RhB was significantly enhanced (100 %) using 4 wt% of AgBr-doped CS-CuFe2O4 catalysts in a basic medium. The significant inhibitory zones (9.25 to 17.95 mm) inhibitory in maximum doses were seen against Gram-positive bacteria (S. aureus). The bactericidal action of AgBr/CS-doped CuFe2O4 NSs against DNA gyraseS.aureus and tyrosyl-tRNAsynthetase S. aureus was rationalized using molecular docking studies, which supported their function as inhibitors.

A Facile Glycerol-Assisted Synthesis of Low-Cu2+-Doped CoFe2O4 for Electrochemical Sensing of Acetaminophen

This work devised a simple glycerol-assisted synthesis of a low-Cu2+-doped CoFe2O4 and the electrochemical detection of acetaminophen (AC). During the synthesis, several polyalcohols were tested, indicating the efficiency of glycerin as a cosolvent, aiding in the creation of electrode-modifier nanomaterials. A duration of standing time (eight hours) before calcination produces a decrease in the secondary phase of hematite. The synthesized material was used as an electrode material in the detection of AC. In acidic conditions (pH 2.5), the limit of detection (LOD) was 99.4 nM, while the limit of quantification (LOQ) was found to be (331 nM). The relative standard deviation (RSD), 3.31%, was computed. The enhanced electrocatalytic activity of a low-Cu2+-doped CoFe2O4-modified electrode Cu0.13Co0.87Fe2O4/GCE corresponds extremely well with its resistance Rct, which was determined using the electrochemical impedance spectroscopy (EIS) technique and defined its electron transfer capacity. The possibility of a low-Cu2+-doped CoFe2O4 for the electrochemical sensing of AC in human urine samples was studied. The recovery rates ranging from 96.5 to 101.0% were obtained. These findings suggested that the Cu0.13Co0.87Fe2O4/GCE sensor has outstanding practicability and could be utilized to detect AC content in real complex biological samples.

Molten salt synthesis of disordered spinel CoFe2O4 with improved electrochemical performance for sodium-ion batteries

Sodium-ion (Na-ion) batteries are currently being investigated as an attractive substitute for lithium-ion (Li-ion) batteries in large energy storage systems because of the more abundant and less expensive supply of Na than Li. However, the reversible capacity of Na-ions is limited because Na possesses a large ionic radius and has a higher standard electrode potential than that of Li, making it challenging to obtain electrode materials that are capable of storing large quantities of Na-ions. This study investigates the potential of CoFe2O4 synthesised via the molten salt method as an anode for Na-ion batteries. The obtained phase structure, morphology and charge and discharge properties of CoFe2O4 are thoroughly assessed. The synthesised CoFe2O4 has an octahedron morphology, with a particle size in the range of 1.1-3.6 μm and a crystallite size of ∼26 nm. Moreover, the CoFe2O4 (M800) electrodes can deliver a high discharge capacity of 839 mA h g-1 in the first cycle at a current density of 0.1 A g-1, reasonable cyclability of 98 mA h g-1 after 100 cycles and coulombic efficiency of ∼99%. The improved electrochemical performances of CoFe2O4 can be due to Na-ion-pathway shortening, wherein the homogeneity and small size of CoFe2O4 particles may enhance the Na-ion transportation. Therefore, this simple synthetic approach using molten salt favours the Na-ion diffusion and electron transport to a great extent and maximises the utilisation of CoFe2O4 as a potential anode material for Na-ion batteries.

Magnetic Nanocomposite Materials Based on Fe3O4 Nanoparticles with Iron and Silica Glycerolates Shell: Synthesis and Characterization

Novel magnetic nanocomposite materials based on Fe3O4 nanoparticles coated with iron and silica glycerolates (MNP@Fe(III)Glyc and MNP@Fe(III)/SiGlyc) were obtained. The synthesized nanocomposites were characterized using TEM, XRD, TGA, VMS, Mössbauer and IR spectroscopy. The amount of iron and silica glycerolates in the nanocomposites was calculated from the Mössbauer spectroscopy, ICP AES and C,H-elemental analysis. Thus, it has been shown that the distribution of Fe in the shell and core for MNP@Fe(III)Glyc and MNP@Fe(III)/SiGlyc is 27:73 and 32:68, respectively. The synthesized nanocomposites had high specific magnetization values and a high magnetic response to the alternating magnetic field. The hydrolysis of shells based on Fe(III)Glyc and Fe(III)/SiGlyc in aqueous media has been studied. It has been demonstrated that, while the iron glycerolates shell of MNP@Fe(III)Glyc is resistant to hydrolysis, the silica glycerolates shell of MNP@Fe(III)/SiGlyc is rather labile and hydrolyzed by 76.4% in 24 h at 25 °C. The synthesized materials did not show cytotoxicity in in vitro experiments (MTT-assay). The data obtained can be used in the design of materials for controlled-release drug delivery.

The Structure, Magnetic, and Gas Sensing Characteristics of W-Substituted Co-Ferrite Nanoparticles

Ferrites have been broadly investigated as gas sensors. The present article reports on the synthesis of Co-ferrite doped with W ions and their gas sensing abilities. A series of single phase CoFe2O4 powder with different W-doping (0.0 ≤ x ≤ 0.15) was synthesized using sol-gel synthesis. A variation in the saturation magnetization (Ms) and the lattice dimension with W(VI) substitution was associated with a change in the distribution of Fe(III) ions between tetrahedral and octahedral sites. Introducing W(VI) ions into the spinel lattice induced the rearrangement of Fe(III) ions. The total Ms increased with W-doping up to x = 0.05 (Ms = 50.1 Am2/kg) and it dramatically decreased to 34.6 Am2/kg with x = 0.15 of doping. However, the lattice parameter increased with increasing doping levels. Different W-doped CoFe2O4 were examined for a gas sensing response in the temperature range of 200–450 °C. Comparing the sensor responses to various reducing gases, the material’s response was shown to be sensitive and selective for acetone. The addition of W (0.15%) had a significant impact on the response and on the operating temperature of the sensor material, indicating that it might be used as an acetone sensor.

Structure–activity correlation in aerobic cyclohexene oxidation and peroxide decomposition over CoxFe3−xO4 spinel oxides

Aerobic cyclohexene oxidation and peroxide decomposition in the liquid phase were performed over a series of CoxFe3−xO4 spinel catalysts exhibiting a volcano plot for the catalytic activity with a maximum at x = 1.

Synthesis and Characterization of New Ferrite-Lignin Hybrids

The paper presents the synthesis and characterization of new cobalt ferrite-lignin hybrids. The hybrids were obtained through the combustion of cobalt nitrate and ferric nitrate, two kinds of lignin being used as combustion agents. The temperatures of calcination were 500 °C and 900 °C, respectively. The hybrids were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The magnetic properties were also assessed by vibrating sample magnetometer system (VSM). This facile synthesis method made it possible to obtain cobalt ferrite-lignin hybrids with a spinel structure. Their particle sizes and crystallite sizes have increased with an increment in the calcination temperature. A different occupancy of cations at octahedral and tetrahedral sites also occurred upon the increase in temperature. The hybrids comprising organic lignin presented the best magnetic properties.

Hydromagnesite sheets impregnated with cobalt-ferrite magnetic nanoparticles as heterogeneous catalytic system for the synthesis of imidazo[1,2-a]pyridine scaffolds

This paper manifests an A³-coupling strategy assisted by novel hydromagnesite sheets impregnated with cobalt ferrite (CoFe₂O₄-HMS) magnetic nanoparticles (MNPs) as an environmentally benign nanocomposite to synthesize imidazo[1,2-a]pyridine scaffolds under ultrasonication. The synthesis of these biologically active derivatives was achieved through A³-coupling employing 2-aminopyridines derivatives, pertinent aryl aldehydes, and phenylacetylene in the presence of polyethylene glycol 400 (PEG 400) as a green solvent under aerobic conditions. Based on its high product yield (up to 94%) in a short reaction time, with a modest catalyst loading, excellent catalyst, and solvent recyclability without substantial loss of operation (up to five synthetic cycles), as demonstrated by the high ecological compatibility and sustainability factors, this strategy follows the principles of green chemistry. The synthesized nanocomposite was characterized via several spectroanalytical techniques, including PXRD, FE-SEM, HR-TEM, EDAX, ICP-AES, FT-IR, Raman spectroscopy, CO₂-TPD, TGA-DTA-DTG analyses, magnetic studies, and nitrogen porosimetry. Furthermore, the structures of synthesized compounds were confirmed based on FT-IR, ¹H NMR, ¹³C NMR, mass spectroscopy, and elemental analysis data.

Sustainable synthesis of imidazo[1,2-a]pyridine scaffolds assisted by hydromagnesite sheets impregnated with cobalt–ferrite (CoFe₂O₄-HMS) magnetic nanoparticles (MNPs).

Aminodextran Coated CoFe2O4 Nanoparticles for Combined Magnetic Resonance Imaging and Hyperthermia

Aminodextran (AMD) coated magnetic cobalt ferrite nanoparticles are synthesized via electrostatic adsorption of aminodextran onto magnetic nanoparticles and their potential theranostic application is evaluated. The uncoated and aminodextran-coated nanoparticles are characterized to determine their hydrodynamic size, morphology, chemical composition, zeta potential and magnetization. The aminodextran containing cobalt ferrite nanoparticles of nanometer size are positively charged in the pH range from 3 to 9 and exhibit saturation magnetization of 50 emu/g. The magnetic resonance imaging (MRI) indicates capability for diagnostics and a reduction in intensity with an increase in nanoparticle amount. The hyperthermia capability of the prepared particles shows their potential to generate suitable local heat for therapeutic purposes. There is a rise of 7 °C and 9 °C at 327 kHz and 981 kHz respectively and specific absorption rates (SAR) of aminodextran-coated nanoparticles are calculated to be 259 W/g and 518 W/g at the given frequencies larger than uncoated nanoparticles (0.02 W/g). The development of novel aminodextran coated magnetic cobalt ferrite nanoparticles has significant potential to enable and improve personalized therapy regimens, targeted cancer therapies and ultimately to overcome the prevalence of nonessential and overdosing of healthy tissues and organs.

Preparation and Magnetic Properties of CoFe2O4 Oriented Fiber Arrays by Electrospinning

The morphology of magnetic materials has a great influence on the properties, which is attributed to the magnetic anisotropy of the materials. Therefore, it is worth studying the fabrication of the aligned fiber and the change of its domain distribution. Nanoparticles and nanofibers were prepared by the hydrothermal and electrospinning methods, respectively. At the same time, the arranged nanofibers were collected by the drum collecting device. After the same annealing at 700 °C, it was found that the diameter of fibers collected by different collecting drums is similar. By studying the hysteresis loops of nanoarrays, it was found that they had strong anisotropy. The easy axis was parallel to the long axis, the Hc and Mr of the easy axis and the hard axis were 1330.5 Oe, 32.39 Am²/kg, and 857.2 Oe, 24.8 Am²/kg, respectively. Due to the anisotropy of the shape and the interaction between the particles, the Hc could not be enhanced. Therefore, the Ms and Hc of the nanoparticles were 80.23 Am²/kg and 979.3 Oe, respectively. The hysteresis loop and the change of magnetic moment during the demagnetization of the CoFe₂O₄ nanofiber array were simulated via micromagnetic software. The simulated Hc was 1480 Oe, which was similar to the experimental value.

Nanosized Pinning Centers in the Rare Earth-Barium-Copper-Oxide Thin-Film Superconductors

Since the discovery of high-temperature superconductivity, significant progress in the fabrication of REBCO-based (Rare Earth Barium Copper mixed Oxides) thin-films superconductors has been achieved. In our review, we described the approaches and possibilities of the improvement of superconducting properties by the introduction of nanosized pinning centers. We focused on the synthesis and viability of the material for artificial pinning centers and methods used for the introduction of the pinning centers into superconducting REBCO-based thin-films. This article summarizes available materials and procedures regardless of the financial cost of the individual method. According to available literature, the most significant superconducting REBCO tapes can be obtained when a combination of 1D and 0D nanoparticles are used for nanoscale pinning.

Highly efficient nanostructured CoFe2 O4 thin film electrodes for electrochemical degradation of rhodamine B

In this work, we report the application of highly efficient electrodeposited cobalt ferrite (CoFe₂ O₄ ) thin films in electrochemical degradation of rhodamine B. XRD, FTIR and Raman spectroscopic studies confirmed the formation of single phase CoFe₂ O₄ . SEM analysis revealed a very fine nanorods dispersed uniformly with average size around 30 nm. UV-Vis spectrophotometry emphasized that the optical band gap value is 1.6 eV. Moreover, the elaborated CoFe₂ O₄ thin films showed a good efficiency for the electrochemical degradation of an aqueous solution of rhodamine B (RhB) attaining 99% during the first 3 min of reaction time. The trapping experiments revealed that the hydroxyl radicals were the main active species leading to the removal of RhB initial concentration of 10 mg/L in a very short time. PRACTITIONER POINTS: A simple electrodeposition technique was used to fabricate CoFe₂ O₄ thin. XRD and FTIR studies revealed the formation of pure cubic spinel phase. Nano-rod like morphology has been successfully synthesized. The rhodamine B aqueous solution has been completely decolorized using the obtained CoFe₂ O₄ thin films.