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The article presents a comprehensive investigation of the crystal structure, impedance spectra, magnetic, magnetodielectric, and magnetoresistive properties of (1- x)CoFe 2 O 4 – x PbTiO 3 composites with varying concentrations (х = 0, 0.2, 0.4, and 0.6). The study also examines the effects of applying a uniaxial pressure of 1 GPa to the synthesized powders using Bridgman anvils. Our findings reveal that the synthesis of these composites results in the formation of an additional phase, lead hexaferrite PbFe 12 O 19 , which exhibits multiferroic properties. Additionally, the coherent scattering region of the components is significantly reduced after mechanical activation. Notably, the real part of the resistivity ρ ′(ω) of nanostructured CoFe 2 O 4 ceramics increases eightfold at T = 240 °C. The composites demonstrate significant magnetoresistance at room temperature, reaching up to 250 %. The study also reveals that the signs of the magnetodielectric MD (B) and magnetoresistive coefficient MR (B) vary with the frequency of the measuring field for certain concentrations. Using the first-order reversal curve (FORC) method, it was observed that after nanostructuring CoFe 2 O 4 through mechanical activation, the interaction field H u shifts from ± 0.6 kOe to ± 0.8 kOe, while the coercive field H c increases from 1.05 kOe to 5 kOe. Moreover, the two-dimensional FORC maps of the composites show increased complexity, due to the formation of additional magnetic phases. [ABSTRACT FROM AUTHOR]

Global industrialization has led to a pressing concern of water pollution from refractory reactive dyes. Among Advanced oxidation processes, the Fenton photocatalyst, particularly cobalt ferrite (CoFe2O4), is gaining attention due to its advantages, including stability, visible light utilization, recyclability, cost-effectiveness, and light corrosion resistance. This study investigates the synthesis and application of cobalt ferrite magnetic nanoparticles (CFNs) as a Fenton-like catalyst for degrading Reactive Blue 19 (RB19) dye under UV irradiation. CFNs were characterized using XRD, SEM, and VSM techniques. The photo degradation of RB19 was assessed under various conditions, including catalyst dosage, oxidant amount, RB19 concentration, and pH. The maximum removal efficiency of RB19 was achieved as 97.3% for synthetic wastewater under the optimal conditions of pH 3, CoFe2O4 dosage (1.5 g/L), reaction time = 60 min, and H2O2 (80 mM) in the presence of UV radiation (18 W) at the ambient room temperature of 22 °C. The results revealed that the CFNs exhibited high stability, reusability, and catalytic activity. Moreover, the mineralization studies indicated significant removal rates for both RB19 and chemical oxygen demand (COD). The findings suggest the promising application of CFNs in advanced wastewater treatment processes. [ABSTRACT FROM AUTHOR]

Improving the efficiency of bifunctional electrocatalysts is a decisive challenge in the area of long‐lasting rechargeable zinc‐air batteries. Enhancing the catalysts' performance is crucial for advancing zinc‐air batteries. Transition‐metal oxides have emerged as promising non‐precious, noble‐metal‐free catalysts. Herein, a unique precursor directed approach is introduced for preparing a cobalt ferrite@nitrogen doped carbon nanohorns (CoFe2O4@N‐CNHs) nanohybrid catalyst in a single step annealing process involving stoichiometric amounts of single‐source cobalt and iron molecular precursors and carbon nanohorns (CNHs) under an argon/ammonia (Ar/NH3) atmosphere. This procedure enables a simultaneous CoFe2O4 ferrite synthesis and nitrogen functionalization of CNHs. The precious metal free nanohybrid CoFe2O4@N‐CNHs‐30% containing 30% of carbon presents an oxygen reduction reaction (ORR) half wave potential and onset potential comparable to the standard ORR catalyst 20% Pt/C. CoFe2O4@N‐CNHs‐30% also establishes superior oxygen evolution reaction (OER) performance with a low overpotential and a small Tafel slope than benchmark OER catalyst RuO2. Furthermore, the rechargeable zinc‐air battery with the CoFe2O4@N‐CNHs‐30% nanohybrid as air electrode demonstrates steadier and more durable charge–discharge cycles, and outstanding energy density relative to the state‐of‐the‐art 20% Pt/C‐RuO2 catalyst. [ABSTRACT FROM AUTHOR]

This study is an attempt to compare the hyperthermia and antimicrobial activity of three members of the family of spinel ferrite magnetic nanoparticles (XFe2O4, where X = Mg, Cu, and CO) MNPs. Spinell ferrite of MgFe2O4, CuFe2O4, and CoFe2O4 were prepared via sol–gel method. Structural and morphological shapes were investigated by different techniques X-ray diffraction X-ray powder diffractometer (XRD), Fourier transformed infrared spectroscopy (FTIR), and (Transmission electron microscope) TEM. Magnetic properties were examined by vibrating sample magnetometer (VSM). The in vitro test was conducted on cervical Hela cells using an MTT assay. Finally, the antimicrobial activity was tested on Staphylococcus aureus, Bacillus subtlus, and Escherichia coli using a clearing inhibition zone. XRD results confirmed the crystalline nature of MgFe2O4, CuFe2O4, and CoFe2O4. VSM results showed a high maximum saturation (Ms = 44.87 emu/g) of CuFe2O4 which is greater than that of CoFe2O4 and MgFe2O4 (18.221 and 18.669) emu/g, respectively. MTT assay revealed that high cell death was detected on Hela cells of CuFe2O4 compared to that of MgFe2O4 and CoFe2O4. The anti-microbial study showed that the prepared spinel magnetic nanoparticles possessed antimicrobial activity due to the release of Mg, Cu, Co, and Fe ions. Results showed that the CuFe2O4 could be a good spinel ferrite for medical application with antimicrobial activity and generate heat (hyperthermia, anti-cancer material). [ABSTRACT FROM AUTHOR]

The development of new catalytic systems based on cobalt and iron compounds for the production of oxygen-containing compounds is an urgent task of chemical technology. The purpose of this work is the synthesis of CoFe2O4 stabilized with polyvinylpyrrolidone (PVP), the study of the catalyst by physico-chemical research methods, and the determination of the effectiveness of the CoFe2O4/PVP catalyst in the phenol oxidation reaction. In this work, magnetic composites CoFe2O4 and CoFe2O4 stabilized with polyvinylpyrrolidone were synthesized by co-deposition. A comparison of the characteristics of the properties of the synthesized cobalt (II) ferrite (CoFe2O4) and the composite material CoFe2O4/PVP based on it is carried out. The obtained samples were examined using X-ray phase analysis (XRD), the Debye–Scherrer method, scanning electron microscopy (SEM), Mossbauer and IR Fourier spectroscopy, as well as thermogravimetric analysis (TGA). The textural properties were determined based on the analysis of nitrogen isotherms. The catalytic properties of the synthesized materials in the process of phenol oxidation in the presence of hydrogen peroxide are considered. The analysis of the reaction mixtures by HPLC obtained by the oxidation of phenol in the presence of a CoFe2O4/PVP catalyst showed a decrease in the concentration of phenol in the first 15 min of the process (by 55–60%), and then within 30 min, the concentration of phenol decreased to 21.83%. After 2 h of the process, the conversion of phenol was already more than 95%. The final sample after the reaction contained 28% hydroquinone and 50% benzoquinone. It was found that the synthesized magnetic composites exhibit catalytic activity in this process. [ABSTRACT FROM AUTHOR]

The present study focuses on the modification induced by 200 MeV Ag15+ and 100 MeV O7+ ion irradiations on the structural, surface morphological, and magnetic properties of radio frequency sputtered CoFe2O4 (CFO) thin films grown on SiO2/Si (100) substrates. X‐ray diffraction shows amorphization of the CFO thin films when irradiated with Ag ions and varies with fluences. This effect is absent in the case of O ion irradiated CFO films. These results are consistent with the measurements from the Raman spectroscopy, where the intensities of Eg and T2g modes are significantly reduced and further disappear in the high fluence. The surface morphology of the O ion irradiated films is dramatically different from the pristine and Ag ion irradiated films where the surfaces appear in nanopillars‐like patterns. The topography of the O ion irradiated films appears to be like hill and valley structures, the roughness first increases (from 10.11 to 24.39 nm). Then it decreases to 18.93 nm on further increasing ion fluence. The coercivity, remnant magnetization, and saturation magnetization increase upon irradiation at low fluence 5 × 1011 ions/cm2 for both the ion beams and then downturn with the increase of fluence 5 × 1012 ions/cm2. The changes in the magnetic and structural characteristics are ascribed to the defects induced by ion irradiation. These results are understood based on the structural and surface modifications induced by the electronic excitation of Ag and O ions. The study depicts that a controlled selection of ions and beam fluence can tailor the structure, morphology, and magnetic properties of ferrite films. [ABSTRACT FROM AUTHOR]

As a kind of magnetostrictive ceramics, cobalt ferrites are widely concerned because of its large magnetostriction and high resistivity, which are ideal for high-frequency applications. But, the high driving magnetic field due to the high magnetocrystalline anisotropy limits the practical applications of cobalt ferrites, thus, it is a still a challenge to find a balance between high magnetostriction properties and low driving magnetic fields. In this work, we investigated the effects of partially substitution of Ga3+ for Fe3+ on grain orientation and magnetic properties, attempting to maintain high magnetostriction while reducing the driving magnetic field. The CoFe 2-x Ga x O 4 (x=0, 0.05, 0.1, 0.15) with single-phase spinel structure were prepared by the conventional solid-state method. The saturation magnetization M S increased with the increase of Ga concentration, meanwhile the coercivity H c and magnetocrystalline anisotropy constant K 1 significantly decreased, which indicates the better soft magnetic characteristics of the Ga-doped cobalt ferrites. The oriented CoFe 2-x Ga x O 4 samples were obtained using magnetic field orientation technique during the powder forming process. The <001> preferred orientation was achieved in CoFe 2 O 4 samples. However, the <001> orientation degree decreased with the substitution of Ga, and the preferred orientation has changed into <111> at x=0.15. The Ga substitution affected the magnetocrystalline anisotropy and grain orientation, thereby affecting the magnetostrictive properties. As for the non-oriented samples, although the maximum magnetostrictive strain slightly decreased with Ga substitution, while there was a significant drop in the magnetostrictive saturation field. However, the magnetostriction of the oriented samples decreased significantly with the substitution of Ga due to the change of grain orientation from <001> to <111>. [ABSTRACT FROM AUTHOR]

Given that tumor microenvironment (TME) exerts adverse impact on the therapeutic response and clinical outcome, robust TME modulators may significantly improve the curative effect and increase survival benefits of cancer patients. Here, Au nanodots‐anchored CoFe2O4 nanoflowers with PEGylation (CFAP) are developed to respond to TME cues, aiming to exacerbate redox dyshomeostasis for efficacious antineoplastic therapy under ultrasound (US) irradiation. After uptake by tumor cells, CFAP with glucose oxidase (GOx)‐like activity can facilitate glucose depletion and promote the production of H2O2. Multivalent elements of Co(II)/Co(III) and Fe(II)/Fe(III) in CFAP display strong Fenton‐like activity for·OH production from H2O2. On the other hand, energy band structure CFAP is superior for US‐actuated 1O2 generation, relying on the enhanced separation and retarded recombination of e−/h+ pairs. In addition, catalase‐mimic CFAP can react with cytosolic H2O2 to generate molecular oxygen, which may increase the product yields from O2‐consuming reactions, such as glucose oxidation and sonosensitization processes. Besides the massive production of reactive oxygen species, CFAP is also capable of exhausting glutathione to devastate intracellular redox balance. Severe immunogenic cell death and effective inhibition of solid tumor by CFAP demonstrates the clinical potency of such heterogeneous structure and may inspire more relevant designs for disease therapy. [ABSTRACT FROM AUTHOR]

Cobalt ferrite–silica–gold nanocomposite (CoFe2O4@SiO2@Au) is synthesized using a new method involving: i) the polyol method for cobalt ferrite nanoparticles (CoFe2O4), ii) the Stober method for silica coating, iii) surface functionalization with 3‐aminopropyl triethoxysilane (APTES), and iv) decoration with gold nanoparticles via tetrakis hydroxy‐methyl‐phosphonium (THPC) reduction. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirm the morphology of the nanoparticles and coatings for the nanocomposites. Ultraviolet–visible (UV–Vis) absorption spectra exhibit plasmon resonance peaks with tuned shifts, discuss in terms of the difference in dielectric permittivity in the core where gold nanoparticles are anchored. Magnetic hysteresis analysis reveals superparamagnetic behavior with reduced saturation magnetization for the nanocomposites. These findings are useful, as superparamagnetic behavior combined with control of plasmonic emission is highly relevant for several magneto‐plasmonic applications. [ABSTRACT FROM AUTHOR]

Methylene blue (MB) contamination in water is one of the key contributors to many chronic health problems, making its eradication one of the most pressing challenges. We report the successful synthesis of cobalt ferrite-graphene nanocomposite (CF-rGO) to eliminate MB from water by adsorption. A facile solvothermal method was employed to prepare CF-rGO nanoadsorbents, and their physical and chemical properties were systematically investigated. The composite shows a saturation magnetization value of 27 emu.g− 1, making it advantageous for the recycling procedure using magnetic separation. It is found that the CF-rGO composite exhibits an adsorption capacity of 15.5 mg.g− 1 within 30 min, successfully removing 93% of MB from water. It further shows good recyclability, with a dye removal efficiency of 78% even at the end of the fifth cycle. The produced CF-rGO adsorbent is thus promising as it is simple to separate, has a high adsorption capacity, is recyclable and is inexpensive. It could be a good candidate for reusable adsorbents for effective adsorption and elimination of MB dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

The widespread environmental contamination resulting from the misuse of tetracycline antibiotics (TCs) has garnered significant attention and study by scholars. Photocatalytic technology is one of the environmentally friendly advanced oxidation processes (AOPs) that can effectively solve the problem of residue of TCs in the water environment. This study involved the synthesis of the heterogeneous magnetic photocatalytic material of CoFe2O4/NaBiO3 via the solvothermal method, and it was characterized using different characterization techniques. Then, the photocatalytic system under visible light (Vis) was coupled with peroxymonosulfate (PMS) to explore the performance and mechanism of degradation of tetracycline hydrochloride (TCH) in the wastewater. The characterization results revealed that CoFe2O4/NaBiO3 effectively alleviated the agglomeration phenomenon of CoFe2O4 particles, increased the specific surface area, effectively narrowed the band gap, expanded the visible light absorption spectrum, and inhibited recombination of photogenerated electron–hole pairs. In the Vis+CoFe2O4/NaBiO3+PMS system, CoFe2O4/NaBiO3 effectively activated PMS to produce hydroxyl radicals (·OH) and sulfate radicals (SO4−). Under the conditions of a TCH concentration of 10 mg/L−1, a catalyst concentration of 1 g/L−1 and a PMS concentration of 100 mg/L−1, the degradation efficiency of TCH reached 94% after 100 min illumination. The degradation of TCH was enhanced with the increase in the CoFe2O4/NaBiO3 and PMS dosage. The solution pH and organic matter had a significant impact on TCH degradation. Notably, the TCH degradation efficiency decreased inversely with increasing values of these parameters. The quenching experiments indicated that the free radicals contributing to the Vis+CoFe2O4/NaBiO3+PMS system were ·OH followed by SO4−, hole (h+), and the superoxide radical (O2−). The main mechanism of PMS was based on the cycle of Co3+ and Co2+, as well as Fe3+ and Fe2+. The cyclic tests and characterization by XRD and FT-IR revealed that CoFe2O4/NaBiO3 had good degradation stability. The experimental findings can serve as a reference for the complete removal of antibiotics from wastewater. [ABSTRACT FROM AUTHOR]

The development of decarbonized synthesis approaches is a critical step in the fabrication of ammonia, an indispensable chemical and a potential carbon–neutral energy carrier. In this regard, the photocatalytic production technology has gained ample attention as a sustainable alternative to energy-intensive and environmentally detrimental Haber–Bosch process. Here, we present cobalt ferrite nanoparticles supported on microporous ZSM-5 type ferrisilicate zeolite as a desirable novel photocatalyst for the ammonia generation. The zeolite introduced as a microporous support increasing the catalytically active sites. A straightforward one-pot sol–gel method was used to synthesize cobalt ferrite (CoFe2O4) and CoFe2O4/ferrisilicate (CF/FS) nanocomposites with various weight percentages (10, 25 and 50%) of CoFe2O4. The photocatalytic performances of the samples in the production of ammonia were investigated under visible light irradiation. The highest rate of NH4+ production (484.74 µmol L−1 h−1) was achieved using the CF50%/FS photocatalyst. The distribution of < 50 nm-sized CoFe2O4 nanoparticles on the surface of the zeolite, as demonstrated by TEM images, and extensive BET surface areas are presented as convincing evidences for the improved photocatalytic activity paticularly in CF50%/FS photocatalyst. [ABSTRACT FROM AUTHOR]

In this work, a current and magnetic field sensor is proposed and experimentally demonstrated utilizing a fiber-optic Mach–Zehnder interferometer (MZI) structure. In our setup, one of the interferometer arms is coated with magnetic nanoparticles. The MZI comprises a laser source emitting an optical signal, split by a coupler into two signals propagated by a reference fiber and a sensor fiber. The sensing fiber is encased in cobalt ferrite (CoFe2O4). Upon exposure to a magnetic field, CoFe2O4 induces vibration in the fiber, modifying the sensor's transmission and causing an imbalance between the optical signals of the interferometer arms. This enables us to evaluate the sensor performance regarding sensitivity, accuracy, and saturation. The nanoparticles were synthesized using the protein sol–gel method, resulting in an average crystallite size of 8, 27, and 67 nm for 623, 773, and 1073 K, respectively. Sample characterizations were conducted through X-ray fluorescence, X-ray diffraction, VSM magnetic measurements, and Mössbauer spectroscopy for further analysis of the performance. The sensor exhibited a linear response, achieving a maximum regression between 93.0% and 98.6% across all sample points in the 0 to 150 Oe range, with an output power of approximately 20 dBm, correlated with the applied magnetic field. Sensitivity was measured at 1.15, 0.93, and 1.41 dB/Oe. Previous studies have correlated the horizontal width of the hysteresis loop with sensor saturation. However, by employing a different coating in this work, we complement these findings by demonstrating that the sensor does not saturate if the maximum applied field is smaller than the hysteresis loop width. [ABSTRACT FROM AUTHOR]

This article addresses the thermomechanical thermal buckling and free vibration response of a novel smart sandwich nanoplate based on a sinusoidal higher-order shear deformation theory (SHSDT) with a stretching effect. In the proposed sandwich nanoplate, an auxetic core layer with a negative Poisson's ratio made of Ti-6Al-4V is sandwiched between Ti-6Al-4V rim layers and magneto-electro-elastic (MEE) face layers. The MEE face layers are homogenous volumetric mixtures of cobalt ferrite (CoFe2O4) and barium titanate (BaTiO3). The mechanical and thermal material properties of the auxetic core and MEE face layers are temperature-dependent. Using Hamilton's principle, governing equations are constructed. To characterize the size-dependent behavior of the nanoplate, governing equations are adapted with the nonlocal strain gradient theory (NSGT). By applying the principles of Navier's technique, closed-form solutions are obtained. Parametric simulations are carried out to examine the effects of auxetic core parameters, temperature-dependent material properties, nonlocal parameters, electric, magnetic, and thermal loads on the free vibration and thermal buckling behavior of the nanoplate. According to the simulation results, it is determined that the auxetic core parameters, temperature-dependent material properties, and nonlocal factors significantly affect the thermomechanical behavior of the nanoplate. The outcomes of this investigation are expected to contribute to the advancement of smart nano-electromechanical systems, transducers, and nanosensors characterized by lightweight, exceptional structural integrity and temperature sensitivity. Also, the auxetic core with a negative Poisson's ratio provides a metamaterial feature, and thanks to this feature, the proposed model has the potential to be used as an invisibility technology in sonar and radar-hiding applications. [ABSTRACT FROM AUTHOR]

Abstract The development of decarbonized synthesis approaches is a critical step in the fabrication of ammonia, an indispensable chemical and a potential carbon–neutral energy carrier. In this regard, the photocatalytic production technology has gained ample attention as a sustainable alternative to energy-intensive and environmentally detrimental Haber–Bosch process. Here, we present cobalt ferrite nanoparticles supported on microporous ZSM-5 type ferrisilicate zeolite as a desirable novel photocatalyst for the ammonia generation. The zeolite introduced as a microporous support increasing the catalytically active sites. A straightforward one-pot sol–gel method was used to synthesize cobalt ferrite (CoFe2O4) and CoFe2O4/ferrisilicate (CF/FS) nanocomposites with various weight percentages (10, 25 and 50%) of CoFe2O4. The photocatalytic performances of the samples in the production of ammonia were investigated under visible light irradiation. The highest rate of NH4 + production (484.74 µmol L−1 h−1) was achieved using the CF50%/FS photocatalyst. The distribution of

The present work reports the synthesis of cobalt ferrite and its nanohybrids with polythiophene (PTh) in the weight ratios of 10% and 20%. The ferrite and its nanohybrids were characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy coupled with elemental mapping (Fe-SEM) to confirm the morphology as well as the structure of the synthesized nanohybrids. The nanohybrids were tested for their photocatalytic activity upon modification of PTh against Alizarin Yellow (AY), Congo Red (CR) and Brilliant Blue (BB). Almost 100% degradation was achieved in 30 min using 50 mg of the photocatalyst. The effect of catalyst concentration and dye concentration was also investigated to explore optimum concentration of the photocatalyst required for rapid degradation of the dye. The generation of radicals responsible for degradation was analyzed by radical scavenging experiments and a probable mechanism of degradation was proposed. [ABSTRACT FROM AUTHOR]

We present a novel method for fabricating dense and nanopatterned porous cobalt ferrite (CoFe2O4) thin films with a remarkable thickness of 65 nm, achieved through direct block copolymer self‐assembly. By decomposing the block copolymer and inducing crystallization of the spinel phase, we successfully produce films exhibiting quasi‐hexagonal arrays of pores with an average diameter ranging from 60 to 80 nm. The resulting nanopatterned porous thin films demonstrate exceptional orderliness, as the pores are intricately designed by the cobalt ferrite grains, and the platinum substrate offers complete accessibility in the pore area. Our findings reveal high magnetization values, comparable to those of bulk CoFe2O4, in the dense film. Additionally, in the case of the nanopatterned porous film, we observed a distinctive contribution of perpendicular magnetization. This innovative approach holds great promise for advanced magnetization and thin‐film engineering applications. [ABSTRACT FROM AUTHOR]

Inkjet printing is a versatile and cheap technique for the fabrication of films, offering unique advantages in terms of scalability, precision, and customization. In recent years, there has been a growing interest in utilizing inkjet printing technology for the deposition of magnetic films with tailored properties. Cobalt ferrite (CoFe2O4) stands out due to its exceptional magnetic properties, including high coercivity, saturation magnetization, and excellent chemical stability. This paper presents a comprehensive study on the inkjet printing of cobalt ferrite magnetic films, focusing on the manufacturing process, especially on the different factors that could lead to stable multilayer depositions to achieve high thicknesses: ink solid loading, drop spacing, substrate temperature, and interlayers drying. Finally, the microstructure of the samples is investigated to identify the occurring defects after sintering between 800 and 1000 °C. The magnetic properties of the films are determined, revealing a maximum coercivity of 1.98 kOe and a magnetic saturation of 78.25 emu cm−3. [ABSTRACT FROM AUTHOR]

8-Hydroxyquinoline and its derivatives are compounds with a variety of applications in various fields of knowledge such as medicine, biological sciences, and chemistry. Many of these applications are possible because 8-hydroxyquinoline forms stable and insoluble metal chelates with a range of metals such as copper, cobalt, calcium, iron, and nickel. One of the possible applications of 8-HQ chelates is the production of metal oxides by thermal decomposition, however, there are few studies in the literature using quinolinates for this purpose. If the chelates are synthesized simultaneously, it is possible to obtain double oxides such as cobalt ferrite, which has numerous applications due to its magnetic properties. In this way, the present work aims to the simultaneous synthesis of cobalt II and iron III quinolinates at different pH values, as well as their characterization by XDR, SEM, TEM, FTIR and Raman analysis. Finally, the quinollinate synthetized were applied as precursors to obtain cobalt ferrite by thermal decomposition. [ABSTRACT FROM AUTHOR]

The study encompasses an investigation of optical, photothermal and biocompatibility properties of a composite consisting of golden cores surrounded by superparamagnetic CoFe2O4 nanoparticles. Accompanied with the experiment, the computational modeling reveals that each adjusted magnetic nanoparticle redshifts the plasmon resonance frequency in gold and nonlinearly increases the extinction cross‐section at ~800 nm. The concentration dependent photothermal study demonstrates a temperature increase of 8.2 K and the photothermal conversion efficiency of 51% for the 100 μg/mL aqueous solution of the composite nanoparticles, when subjected to a laser power of 0.5 W at 815 nm. During an in vitro photothermal therapy, a portion of the composite nanoparticles, initially seeded at this concentration, remained associated with the cells after washing. These retained nanoparticles effectively heated the cell culture medium, resulting in a 22% reduction in cell viability after 15 min of the treatment. The composite features a potential in multimodal magneto‐plasmonic therapies. [ABSTRACT FROM AUTHOR]

The paper presents a novel method for obtaining cobalt ferrites with a spinel type structure under the action of a nonequilibrium atmospheric pressure gas-discharge plasma in air on a mixture of solid iron and cobalt hydroxonitrates. The data of energy dispersive X-ray spectroscopy and X-ray phase analysis showed that the synthesized powders have a complex phase and chemical composition, which depends on the Fe:Co molar ratio in the initial salts. The best result in terms of yield of cobalt ferrite is obtained with Fe:Co = 2:1. The resulting material contains 86 wt% Fe2CoO4, also 13.5 wt% Fe2O3 and 0.5 wt% Fe3O4. At other ratios, Co3O4 is also formed. According to dynamic light scattering data, the obtained powders consist of two characteristic fractions. The main fraction (94%) is represented by particles 105 ± 4 nm in size. And the other fraction (6%) consists of particles 18 ± 4 nm in size. The resulting materials have magnetic properties. So, for powders obtained from salts with Fe:Co = 2:1 the coercive force was 490 Oe. The saturation magnetization was 52 emu/g, and the remnant magnetization was 22 emu/g. [ABSTRACT FROM AUTHOR]

This research investigates the impact of physicochemical properties on the thermochemical redox ability of CoFe 2 O 4 for water splitting application. Three samples with different properties (CFO-A, CFO-B, and CFO-C) are evaluated. The results reveal that particle size, Co/Fe ratio, and the spinel inversion degree notably affect the redox behavior and sintering of the material. The sample with the smallest particle size (CFO-A, 14 nm) exhibits the most pronounced sintering and the lowest redox performance. Meanwhile, the H 2 production results show the effect of the Co/Fe ratio and spinel inversion. The sample with Co/Fe = 0.5 (CFO–B), exhibits the highest H 2 production (595 μmol g−1), compared to the samples with Co/Fe = 0.6 (CFO-A and CFO-C). Thermodynamic calculations support these findings, suggesting that the thermochemical water splitting reaction is thermodynamically more favorable with a Co/Fe ratio = 0.5. The spinel inversion degree also influences the performance of the material, since CFO-B, the most efficient sample, shows the lowest inversion degree (67 %), compared to CFO-A and CFO-C (70 and 68 %). These results stress the importance of thoroughly controlling the physicochemical properties of the active redox material. [Display omitted] • Effect of material properties on thermochemical water splitting is evaluated. • Particle size <20 nm promotes highest sintering and lowest performance. • Co/Fe = 0.5 and lowest spinel inversion boosted the highest H 2 production (595 μmol g−1). • Thermodynamic study corroborates higher reoxidation feasibility for Co/Fe = 0.5. [ABSTRACT FROM AUTHOR]

AbstractMagnetic Ferrite nanoparticles (MFNPs), are promising for diverse application owing to their divergent functional properties. Among the MFNPs cobalt ferrite nanocomposites have gained a lot of attention for myriad biomedical application. This paper describes our synthesis of nickel doped cobalt ferrite capped in polyethylene glycol (PEG), polyvinyl alcohol (PVA) and polyvinyl pyrolidone (PVP) by a hydrothermal method. Several characterizations techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) were used to determine the physico-chemical properties of the formulated MFNPs. The physico-chemical properties of the MFNPs were influenced by the PEG, PVA and PVP. The formulated nanoparticles showed enhanced antidiabetic, antioxidant and antimicrobial activities. The PVP capped MFNPs, had the highest antifungi and antidiabetic activities, while the PVA capped MFNPs showed the highest antibacterial and antioxidant activities. Hence, the introduction of these polymers in the samples heightened their biomedical performance. The photodegradation of crystal violet by the MFNPs was also enhanced with the PVP mediated sample having the highest efficiency. [ABSTRACT FROM AUTHOR]

A cobalt ferrite (CoFe2O4) nanoparticle is harvested through sol–gel method. The various percentage of PVP (2.5, 5.0, 7.5, 10.0 and 12.5%) was added to the initial solutions and is acted as a chelating agent. Through X-Ray diffraction examinations results confirmed the single phase CoFe2O4 and had bigger crystallite size. The functional analysis is found through Fourier transform infrared spectroscopy (FTIR) studies. The optical analysis carried out through UV–visible spectrometer and a direct bandgap were determined. The surface features and its content of elements in the samples were found through scanning electron microscope (SEM) with energy dispersive (EDAX) analysis. The detailed magnetic characteristics of the resulting sample were found through vibrating sample magnetometer (VSM). Through TG/DTA measurements the decompositions and anionic oxidation—reduction were analysed. The dielectric constant and related parameters with respect to applied frequency are discussed through LCR measurement. The electrochemical behavior of the samples was tested through cyclic voltameter setup. And finally concluded with the merits and demerits. [ABSTRACT FROM AUTHOR]

Abstract Improving the efficiency of bifunctional electrocatalysts is a decisive challenge in the area of long‐lasting rechargeable zinc‐air batteries. Enhancing the catalysts' performance is crucial for advancing zinc‐air batteries. Transition‐metal oxides have emerged as promising non‐precious, noble‐metal‐free catalysts. Herein, a unique precursor directed approach is introduced for preparing a cobalt ferrite@nitrogen doped carbon nanohorns (CoFe2O4@N‐CNHs) nanohybrid catalyst in a single step annealing process involving stoichiometric amounts of single‐source cobalt and iron molecular precursors and carbon nanohorns (CNHs) under an argon/ammonia (Ar/NH3) atmosphere. This procedure enables a simultaneous CoFe2O4 ferrite synthesis and nitrogen functionalization of CNHs. The precious metal free nanohybrid CoFe2O4@N‐CNHs‐30% containing 30% of carbon presents an oxygen reduction reaction (ORR) half wave potential and onset potential comparable to the standard ORR catalyst 20% Pt/C. CoFe2O4@N‐CNHs‐30% also establishes superior oxygen evolution reaction (OER) performance with a low overpotential and a small Tafel slope than benchmark OER catalyst RuO2. Furthermore, the rechargeable zinc‐air battery with the CoFe2O4@N‐CNHs‐30% nanohybrid as air electrode demonstrates steadier and more durable charge–discharge cycles, and outstanding energy density relative to the state‐of‐the‐art 20% Pt/C‐RuO2 catalyst.

Abstract Given that tumor microenvironment (TME) exerts adverse impact on the therapeutic response and clinical outcome, robust TME modulators may significantly improve the curative effect and increase survival benefits of cancer patients. Here, Au nanodots‐anchored CoFe2O4 nanoflowers with PEGylation (CFAP) are developed to respond to TME cues, aiming to exacerbate redox dyshomeostasis for efficacious antineoplastic therapy under ultrasound (US) irradiation. After uptake by tumor cells, CFAP with glucose oxidase (GOx)‐like activity can facilitate glucose depletion and promote the production of H2O2. Multivalent elements of Co(II)/Co(III) and Fe(II)/Fe(III) in CFAP display strong Fenton‐like activity for·OH production from H2O2. On the other hand, energy band structure CFAP is superior for US‐actuated 1O2 generation, relying on the enhanced separation and retarded recombination of e−/h+ pairs. In addition, catalase‐mimic CFAP can react with cytosolic H2O2 to generate molecular oxygen, which may increase the product yields from O2‐consuming reactions, such as glucose oxidation and sonosensitization processes. Besides the massive production of reactive oxygen species, CFAP is also capable of exhausting glutathione to devastate intracellular redox balance. Severe immunogenic cell death and effective inhibition of solid tumor by CFAP demonstrates the clinical potency of such heterogeneous structure and may inspire more relevant designs for disease therapy.

Cubic bi-magnetic hard-soft core-shell nanoarchitectures were prepared starting from cobalt ferrite nanoparticles, prevalently with cubic shape, as seeds to grow a manganese ferrite shell. The combined use of direct (nanoscale chemical mapping via STEM-EDX) and indirect (DC magnetometry) tools was adopted to verify the formation of the heterostructures at the nanoscale and bulk level, respectively. The results showed the obtainment of core-shell NPs (CoFe2O4@MnFe2O4) with a thin shell (heterogenous nucleation). In addition, manganese ferrite was found to homogeneously nucleate to form a secondary nanoparticle population (homogenous nucleation). This study shed light on the competitive formation mechanism of homogenous and heterogenous nucleation, suggesting the existence of a critical size, beyond which, phase separation occurs and seeds are no longer available in the reaction medium for heterogenous nucleation. These findings may allow one to tailor the synthesis process in order to achieve better control of the materials' features affecting the magnetic behaviour, and consequently, the performances as heat mediators or components for data storage devices.

A simple approach was developed to synthesize cobalt ferrite nanoparticles/graphene quantum dots (CF/GQDs). The material was prepared from a homogeneous mixture of iron nitrate, cobalt nitrate, and starch at 140, 180 and 200 °C in a 24 h thermal hydrolysis process. The obtained materials were characterised by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, photoluminescence spectroscopy, vibrating-sample magnetometry, and nitrogen adsorption/desorption isotherms. Cobalt ferrite crystals of around 8–10 nm and graphene quantum dots formed directly at 200 °C. Stacking GQDs sheets onto the CF nanoparticles resulted in CF/GQDs nanoparticles. The nanocomposite exhibits satisfactory fluorescent and superparamagnetic properties, which are vital for catalytic applications. The CF/GQDs catalyse significantly the degradation of methylene blue (MB) under visible light. The catalyst can be recycled with an external magnetic field and displays suitable stability. Also, it was reused in three successive experiments with a loss of efficiency of about 5%. The CF/GQDs are considered as an efficient photocatalyst for MB degradation and other dyes.

Recently, there has been a rapid growth in the use of nanoparticles in water treatment processes. However, an important task is to study the toxicity of the materials used and the reaction products formed. The purpose of this study was to evaluate the impact of the proposed water treatment method on the ecosystem. Algae are excellent model organisms for studying the toxic effects of catalyst nanoparticles. This work investigates the toxicity of cobalt ferrite (CoFe2O4) and hydrogen peroxide (H2O2) on the microalgae Chlorella vulgaris Beij. (C. vulgaris). The growth rate of C. vulgaris depends on the residual concentration of H2O2, indicating a stressful physiological state of the microalgae. Exposure to sintered cobalt ferrite granules does not affect the growth of freshwater algae. At a residual H2O2 concentration of 11.9 mM, algal cells' morphology, membrane integrity, and viability were severely impaired. Hydrogen peroxide is known to cause oxidative stress, as evidenced by a decrease in the growth rate of C. vulgaris and an increase in the number of dead cells. The study showed that the high residual concentration of H2O2 is the main obstacle to the discharge of treated water into the natural ecosystem.

The utilization of catalysts in organic reactions represents a widely utilized principle within the concept of green chemistry. This study focuses on utilizing hydroxyapatite from green mussel shell waste combined with CoFe2O4 as a heterogeneous catalyst for synthesizing 2-amino-4H-chromene derivative. The green mussel shells were calcined to produce CaO, which was then utilized as a precursor in the synthesis of hydroxyapatite, and then combined with cobalt ferrite through the coprecipitation method. Diffractogram analysis confirmed successful formation of hydroxyapatite, CoFe2O4, and their composite, validated against JCPDS data. Morphological analysis revealed irregular shapes, while magnetic property analysis indicated a slight decrease in the hydroxyapatite-CoFe2O4 composite compared to pristine CoFe2O4. Catalytic activity assessment demonstrated high yields (up to 88 %) under optimized conditions: catalyst concentration of 7.5 % w/w, reaction time of 15 minutes, in ethanol solvent, and using 300 Watts microwave power. The reusability of hydroxyapatite-CoFe2O4 as a catalyst, supported by the XRD and FTIR analyses, demonstrates its structural and chemical stability after five catalytic cycles, showcasing its potential as an eco-friendly and efficient catalyst.

A series of cobalt ferrite/cadmium oxide (CFO/CO) hetero-junctions were synthesized via an ultra-sonication approach. The compositions were examined based on ferroelectric, optical and photo-catalytic properties. X-ray diffraction (XRD), UV–visible (UV–Vis) spectroscopy and photo-luminescence (PL) were employed for the characterization of the prepared materials. XRD analysis confirmed a distorted cubic phase with space group fm3m and grain size was in 17.6–19.2 nm range. The ferroelectric parameters were enhanced significantly by the addition of CO (CdO) into the CFO (CoFe 2 O 4) crystal lattice. The band-gap energy was decreased significantly of hetero-junctions from 3.29 to 2.54 eV. The enhanced ferroelectric polarization with low band-gap energy boosts their ferroelectric and optical responses. A reduction in PL intensity was observed in hetero-junctions. The photo-catalytic activity (PCA) of CFO and cobalt ferrite/cadmium oxide (1–4) hetero-junctions CFO/CO (1–4) was examined by photo-degradation of Methylene Blue (MB) dye under visible light exposure. The CFO/CO4 photo-catalyst exhibited superior PCA of 92% within 90 min irradiation. Additionally, photo-catalyst dose and pH effect on the kinetics of MB dye degradation was also examined. Superior PCA of CFO/CO4 in comparison to pure CFO makes this material a promising candidate for the removal of hazardous dyes in effluents under visible light irradiation. [ABSTRACT FROM AUTHOR]

The release of hazardous elements by industrial effluents to aquatic ecosystems is a potential threat to the environment. Chromium (Cr) is one of the elements whose levels in several freshwater ecosystems should be reduced to promote water reuse. In recent years, magnetic materials have gained increasing interest as sorbents because of their easy removal from treated water through magnetic separation. In this study, colloidal cobalt ferrite (CoFe2O4) particles were investigated as magnetic sorbents for chromium-aqueous chemical species. The oxidative stress responses of Mytilus galloprovincialis mussels exposed to 200 μg/L of Cr, resembling remediated water, were evaluated. More than 95% of Cr was removed from contaminated solutions by CoFe2O4 aqueous suspensions at pH 6 and pH 10. The kinetics of sorption experiments were examined using pseudo-1st order, pseudo-2nd order and Elovich models to evaluate which mathematical model has a better adjustment to the experimental data. The present study revealed that the levels of Cr that remained in remediated water induced limited biochemical changes in mussels, being considered safe for aquatic systems. Overall, the use of cobalt ferrite–based sorbents may constitute a promising approach to remediate contaminated water. [ABSTRACT FROM AUTHOR]

In this research, a nano-sized cobalt ferrite material doped with Yttrium has been successfully fabricated using the sol-gel method of automatic combustion with variations in low sintering temperatures of 200, 300 and 400 °C. The results of refinement of XRD data using the Rietveld method show that the Yttrium-doped cobalt ferrite compound with a Yttrium concentration molarity of 0.1 possess a cubic crystal system and Fd-3m space group. The increasing annealing temperatures also increase the crystallite size of Yttrium-doped cobalt ferrite with the highest magnitude of 16.05 nm. The FTIR results of the samples indicated the presence of Co-O bonds around wave number 385 cm-1 and Fe-O bonds around wave number 582 cm-1 which are characteristic of the presence of cobalt ferrite compounds. From the VSM measurement results, it can be seen that there is a decrease in magnetic saturation with an increase in annealing temperature. The presence of Yttrium substitution, which takes the place of Fe3+ in cobalt ferrite material, indicates lower saturation magnetization. Image from SEM results showed samples have nanoparticle crystallite size. Evaluation of potential photocatalyst applications using a UV-Visible Spectrophotometer (UV-Vis). For Yttrium doped cobalt ferrite at 200 °C, the best degradation efficiency of Congo Red findings showed a magnitude of 76.10 %; the results are confirmed by the occurrence of the smallest crystallite size (15.11 nm). [ABSTRACT FROM AUTHOR]

In recent times, there has been a significant focus on semiconductive magnetic nanomaterials due to their potential in photocatalytic applications, primarily because of their easy recoverability. In this work, CoY x Fe 2- x O 4 nanoparticles (with varying x values: 0, 0.05, 0.10, 0.15, and 0.20) were successfully synthesized. The incorporation of Y3+ ions induced notable transformations in the structural, optical, microstructural, magnetic, and photocatalytic properties of CoFe 2 O 4 nanoparticles. Analytical techniques such as x-ray diffraction, fourier transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence, transmission electron microscopy, vibrating sample magnetometry, and electron paramagnetic resonance spectroscopy were employed to investigate these effects. The investigation into the photocatalytic degradation of methylene blue (MB) under ultraviolet light irradiation was carried out. The influence of distinct elemental compositions, catalyst quantities, irradiation durations, and initial methylene blue concentrations on the decolorization process was assessed. [ABSTRACT FROM AUTHOR]

This study explores the synthesis and characterization of chitosan/gelatine films incorporating nickel ferrite (NiFe2O4) and cobalt ferrite (CoFe2O4) nanoparticles. The magnetic nanoparticles exhibit superparamagnetic behaviour, making them attractive for various applications, including biomedical uses. The X-ray diffraction analysis confirmed the successful synthesis of NiFe2O4 and CoFe2O4 nanoparticles, and the scanning electron micrographs illustrated well-dispersed ferrite nanoparticles within the biopolymer network, despite the formation of some aggregates attributed to magnetic interactions. Magnetization loops revealed lower saturation magnetization values for the composites, attributed to the chitosan/gelatine coating and the dielectric studies, indicating increased dielectric losses in the presence of ferrites, particularly pronounced in the case of NiFe2O4, suggesting interactions at the interface region between the polymer and ferrite particles. The AC conductivity shows almost linear frequency dependence, associated with proton polarization and conduction processes, more significant at higher temperatures for samples with ferrite particles. [ABSTRACT FROM AUTHOR]

In this present work, spinel cobalt ferrite nanoparticles (CoFe2O4 NPs) and activated carbon-CoFe2O4 nanocomposites (AC-CoFeO4 NCs) were synthesized by simple co-precipitation method and used for photocatalytic dye degradation (PCD) of rhodamine-B (Rh-B) dye. The antimicrobial study of the as-synthesized CoFe2O4 NPs was also performed. The as-synthesized CoFe2O4 NPs and AC-CoFe2O4 NCs were analyzed by ultraviolet spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) studies, scanning electron spectroscopy (FE-SEM) techniques. Powder XRD analysis showed that the as-synthesized CoFeO4 NPs and AC-CoFeO4 NCs had average particle size of 18 nm and 46 nm, respectively. The FE-SEM showed that the CoFe2O4 samples have sphere like morphology and were well decorated on activated carbon in order to provide high surface area. AC-CoFe2O4 NCs have effectively used for the PCD of Rh-B dye with high efficiency. Furthermore, spinel CoFe2O4 NPs acted as a more effective antimicrobial agent against Gram-negative and Gram-positive bacterial strains. Moreover, AC-CoFe2O4 NCs can be used as the precursor materials for supercapacitor, sensors etc. [ABSTRACT FROM AUTHOR]

In this study, Mg1-xCoxFe2O4 (0

We report a new facile method for the synthesis of prolate cobalt ferrite nanoparticles without additional stabilizers, which involves a co-precipitation reaction of Fe3+ and Co2+ ions in a static magnetic field. The magnetic field is demonstrated to be a key factor for the 1D growth of cobalt ferrite nanocrystals in the synthesis. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy are applied to characterize the morphology and structure of the obtained nanoparticles. According to TEM, they represent nanorods with a mean length of 25 nm and a diameter of 3.4 nm that have a monocrystalline structure with characteristic plane spacing of 2.9 Å. XRD and Raman spectroscopy confirm the spinel CoFe2O4 structure of the nanorods. After aging, the synthesized nanorods exhibit maximum saturation magnetization and coercivity equal to 30 emu/g and 0.3 kOe, respectively. Thus, the suggested method is a simple and "green" way to prepare CoFe2O4 nanorods with high aspect ratios and pronounced magnetic properties, which are important for various practical applications, including biomedicine, energy storage, and the preparation of anisotropic magnetic nanocomposites. [ABSTRACT FROM AUTHOR]

This study developed magnetically separable CeO2/CoFe2O4 heterojunction photocatalysts for dye degradation to reduce water pollution. The CeO2/CoFe2O4 nanocomposites with different CeO2 ratios (10, 20, and 30 wt%) were prepared by a precipitation method. The nanocrystalline 20%CeO2/CoFe2O4 photocatalyst with a surface area of 117 m2.g−1, Eg 2.37 eV, and uniform distribution of quasi-spherical CeO2 minor phase (cubic fluorite structure with particle size 3 ± 1 nm) throughout the distorted spherical CoFe2O4 major phase (cubic spinel structure with particle size 9 ± 3 nm) showed the best photocatalytic performance for methylene blue (MB) degradation under UV light irradiation at the efficiency of 88.7% and the apparent rate constant (k) of 0.0138 min−1. The 20%CeO2/CoFe2O4 photocatalyst had a good magnetic response and could be easily separated from the dye solution by applying an external magnetic field. The reusability test showed lower photodegradation efficiency due to the adsorption of residual MB dye on the photocatalyst surface. The formation of heterojunction at the interfaces of CeO2/CoFe2O4 facilitated the photogenerated charge separation and increased availability of active species of holes (h+) and hydroxy radicals (∙OH), which were the key factors in improving the photocatalytic activity. Improved photocatalysis in CeO2-coupled CoFe2O4 composites. Heterojunctions in CeO2/CoFe2O4 increase the availability of active species. External magnetic field separates the photocatalyst from the dye solution. [ABSTRACT FROM AUTHOR]

Abstract We present a novel method for fabricating dense and nanopatterned porous cobalt ferrite (CoFe2O4) thin films with a remarkable thickness of 65 nm, achieved through direct block copolymer self‐assembly. By decomposing the block copolymer and inducing crystallization of the spinel phase, we successfully produce films exhibiting quasi‐hexagonal arrays of pores with an average diameter ranging from 60 to 80 nm. The resulting nanopatterned porous thin films demonstrate exceptional orderliness, as the pores are intricately designed by the cobalt ferrite grains, and the platinum substrate offers complete accessibility in the pore area. Our findings reveal high magnetization values, comparable to those of bulk CoFe2O4, in the dense film. Additionally, in the case of the nanopatterned porous film, we observed a distinctive contribution of perpendicular magnetization. This innovative approach holds great promise for advanced magnetization and thin‐film engineering applications.

Aqueous solutions with heavy metals such as Cr (VI), Pb, and Cd (II) can have an adverse effect on human health because of their toxicity. As a result, it is important to remove these heavy metals from the aquatic environment to save the human healthy. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FE-SEM) used in this research to characterize cobalt ferrite (CoFe2O4) nanoparticles and confirm the structure of Co-Fe2O4. These particles were used to make porous samples and burned at 1050 °C in mixtures of (0, 3, 5, 7, and 10) wt.% of cobalt ferrite and kaolin with 20 wt.% of charcoal. These samples serve as adsorbents that remove Pb from the wastewater. The highest rates of removal were confirmed using various treatments at (pH 3, 7, and 9). A Williamson-Hall plot was used to determine the crystal size (33) nm. The FT-IR spectra exhibited spinel-ferrite characteristics. Studies using FE-SEM demonstrated that the sample was in Nano crystalline. Using a vibrating sample magnetometer (VSM), different magnetic properties are taken from the hysteresis loops such as saturation magnetization (Ms) and remanence (Mr) and coercivity (Hc). It was found that increasing ferrite content, increased adsorption efficiency.

ABSTRACTThis study developed magnetically separable CeO2/CoFe2O4 heterojunction photocatalysts for dye degradation to reduce water pollution. The CeO2/CoFe2O4 nanocomposites with different CeO2 ratios (10, 20, and 30 wt%) were prepared by a precipitation method. The nanocrystalline 20%CeO2/CoFe2O4 photocatalyst with a surface area of 117 m2.g−1, Eg 2.37 eV, and uniform distribution of quasi-spherical CeO2 minor phase (cubic fluorite structure with particle size 3 ± 1 nm) throughout the distorted spherical CoFe2O4 major phase (cubic spinel structure with particle size 9 ± 3 nm) showed the best photocatalytic performance for methylene blue (MB) degradation under UV light irradiation at the efficiency of 88.7% and the apparent rate constant (k) of 0.0138 min−1. The 20%CeO2/CoFe2O4 photocatalyst had a good magnetic response and could be easily separated from the dye solution by applying an external magnetic field. The reusability test showed lower photodegradation efficiency due to the adsorption of residual MB dye on the photocatalyst surface. The formation of heterojunction at the interfaces of CeO2/CoFe2O4 facilitated the photogenerated charge separation and increased availability of active species of holes (h+) and hydroxy radicals (∙OH), which were the key factors in improving the photocatalytic activity.

Background and Objective: The application of different nanoparticles using green synthesis is increasing due to fewer complications. This study was conducted to identify the effect of cobalt ferrite nanoparticles synthesized with sumac extract on changes in biochemical and histological factors in rats. Methods: In this experimental study, 30 five-month-old male Wistar rats with an approximate weight of 250-300 mg/kg of body weight were divided into three groups: The control group (saline receiving), the experimental groups receiving intraperitoneal cobalt ferrite nanoparticles synthesized with sumac extract at a dose of 10 and 20 mg/kg of body weight. Serum and tissue samples (liver, kidney, and spleen) were isolated. Serum concentrations of urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine were determined. The photometric method was used to measure liver enzymes, the calorimetric method without omitting proteins based on the Jaffe method was used to measure creatinine, and the urease-glutamate dehydrogenase (GLDH) method was used to measure urea. Tissue samples were assessed by hematoxylin-eosin staining. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) microscopic studies were used for microscopic investigations. Results: No statistical significance was observed in blood samples and factors (urea, creatinine, ALT, and AST) in the experimental groups compared to the control group. Similarly, in the morphological investigation, the size of the liver, kidney, and spleen of the groups receiving cobalt ferrite nanoparticles synthesized with sumac extract was normal compared to the control group. Conclusion: Cobalt ferrite nanoparticles synthesized with sumac had no toxic effect on the rats’ liver, spleen, and kidney tissues.

Co-precipitation process was used for the synthesis of lanthanum-substituted cobalt ferrite nanoparticles at several annealing temperatures (Ta), i.e., 200 °C, 300 °C, and 400 °C, for 5 h. XRD spectral depicted that the produced nanoparticles sample indicates a single phase of fcc inverse spinel conforming to ICDD No 22-1086. The crystallite size (D) calculation at the strongest peaks shows the increase in enhancing the Ta i.e., 18.99 nm, 19.90 nm, and 23.21 nm for 200 °C, 300 °C, and 400 °C, respectively. The FTIR results showed absorption band at the tetrahedral site, v1 ~575 cm−1 and the octahedral site, v2 ~474 cm−1. The absorption bands indicate that the lanthanum ions have successfully replaced the Fe3+ cations in the original cobalt ferrite structure. According to the hysteresis loop, the coercive field's (HC) magnitude falls from 700 Oe down to 550 Oe as Ta increases. This result is consistent with the anisotropy constant which decreased from 0.77×104 erg/cm3 to 0.56×104 erg/cm3. The obtained nanoparticles also showed superior performance (much larger than 95%) for dye removal of Congo red. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The development of new catalytic systems based on cobalt and iron compounds for the production of oxygen-containing compounds is an urgent task of chemical technology. The purpose of this work is the synthesis of CoFe2O4 stabilized with polyvinylpyrrolidone (PVP), the study of the catalyst by physico-chemical research methods, and the determination of the effectiveness of the CoFe2O4/PVP catalyst in the phenol oxidation reaction. In this work, magnetic composites CoFe2O4 and CoFe2O4 stabilized with polyvinylpyrrolidone were synthesized by co-deposition. A comparison of the characteristics of the properties of the synthesized cobalt (II) ferrite (CoFe2O4) and the composite material CoFe2O4/PVP based on it is carried out. The obtained samples were examined using X-ray phase analysis (XRD), the Debye–Scherrer method, scanning electron microscopy (SEM), Mossbauer and IR Fourier spectroscopy, as well as thermogravimetric analysis (TGA). The textural properties were determined based on the analysis of nitrogen isotherms. The catalytic properties of the synthesized materials in the process of phenol oxidation in the presence of hydrogen peroxide are considered. The analysis of the reaction mixtures by HPLC obtained by the oxidation of phenol in the presence of a CoFe2O4/PVP catalyst showed a decrease in the concentration of phenol in the first 15 min of the process (by 55–60%), and then within 30 min, the concentration of phenol decreased to 21.83%. After 2 h of the process, the conversion of phenol was already more than 95%. The final sample after the reaction contained 28% hydroquinone and 50% benzoquinone. It was found that the synthesized magnetic composites exhibit catalytic activity in this process.