Ferrite MFe2O4 Research Articles

Determine elastic parameters and nanocrystalline size of spinel ferrites MFe2O4 (M = Co, Fe, Mn, Zn) through X-ray diffraction and infrared spectrum: Comparative approach

MFe2O4 (M = Co, Fe, Mn, Zn) nanoparticles were successfully synthesized by coprecipitation. Analyzing the X-ray diffraction by the Rietveld method confirmed the spinel ferrite structure of the samples. Rietveld refinement results show that Co, Mn and Zn occupy both the tetrahedral and octahedral sites. Variation in elastic parameters was determined by Fourier transform infrared spectroscopy, and cation distribution was deduced from X-ray diffraction. X-ray diffraction peak expansion was analyzed by employing a variety of calculating methods such as modified Scherrer, Williamson–Hall, size–strain, and Halder–Wagner to determine the crystallite size and elastic parameters of the cubic-structured MFe2O4 nanoparticles, including intrinsic strain, stress, and energy density. Comparison of the results obtained from these different methods revealed that they are ideally suited to each other. Moreover, the transmission electron microscopy image confirmed that the average size of MFe2O4 (M = Co, Fe, Mn, Zn) nanoparticles ranges from 10 to 14 nm, consistent with the dimensions obtained from the preceding methods.

Synergistic potential in spinel ferrite MFe2O4 (M = Co, Ni) nanoparticles-mediated graphene oxide: Structural aspects, photocatalytic, and kinetic studies

The existence of artificial dyes in water is a significant environmental concern, as it can lead to poor water quality. Photodegradation is becoming an increasingly popular method for treating water contaminated with dyes. In this study, the photodegradation of Reactive Red 66 and Reactive Red 120 dyes, as well as textile wastewater, was investigated under UV and visible light irradiation. To enhance the photoresponse of the MFe2O4 (M = Co, Ni) nanoparticles, modifications were made by incorporating graphene oxide. The MFe2O4 nanoparticles and MFe2O4/GO nanocomposite photocatalysts were subjected to several characterization techniques, including FT-IR, Raman spectroscopy, XRD, DRS, zeta potential, VSM, TGA, DSC, BET, SEM, and EDAX analysis. Experiments were conducted to optimize several key parameters involved in the photodegradation process, including pH, photocatalyst dosage, initial dye concentration, and irradiation time. The removal efficiency of Reactive Red 66 and Reactive Red 120 dyes using CoFe2O4 nanoparticles was found to be 86.97 and 82.63%, respectively. Also, the removal percentage of these dyes using CoFe2O4/GO nanocomposite photocatalyst was 95.57 and 90.9% for Reactive Red 66 and Reactive Red 120, respectively. Experiments found that NiFe2O4 nanoparticles removed 90.92% of Reactive Red 66 dye and 84.7% of Reactive Red 120 dye. The NiFe2O4/GO nanocomposite photocatalyst showed even higher removal efficiencies, degrading 97.96% of Reactive Red 66 and 93.44% of Reactive Red 120. After three days of exposure to visible light irradiation, the removal percentage of Reactive Red 66 using MFe2O4 and MFe2O4/GO nanocomposite was investigated.

Performance evaluation of gas sensors based on spinel ferrites MFe2O4 (M = Cd, Co, Zn) for detecting the linalool

Nanocrystalline powders of spinel ferrites MFe2O4 (M = Cd, Co, Zn) were prepared via a simple sol–gel method, followed by the subsequent annealing. The structural and morphological characterizations of the samples were carried out by different spectroscopic techniques. The influence of the substituted metal (M), reaction time, and temperature on the gas-sensing performance of the as-synthesized CdFe2O4, CoFe2O4 and ZnFe2O4 spinel ferrites for linalool, as an important compound of black tea, were investigated. It is shown that the CdFe2O4 sensor exhibited better sensing performances toward linalool gas at operating temperature of 250 °C. These results indicate that the CdFe2O4 nano-ferrite may be a promising candidate for detection of linalool for estimation of tea quality.

Microstructural evolution and catalytic properties of novel high-entropy spinel ferrites MFe2O4 (M= Mg, Co, Ni, Cu, Zn)

A novel class of high-entropy (HE) spinel ferrites (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)Fe2O4, have been successfully synthesized by the solution combustion synthesis method followed by heat-treatment at 500–1500 °C. The resultant spinel ferrites were systematically investigated by various methods including XRD, SEM, TEM, EDS, Raman spectra, etc. It was demonstrated that the entropy drives a reversible transformation between a single-phase state and multiphase. And the entropy predominates the thermodynamic landscape. The as-fabricated high-entropy (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)Fe2O4 solid solution is single-phase with homogeneous transition-metal element distribution. Moreover, a trade-off between grain growth and crystallization during heat-treatment process; the average grain size of product is only 352.96 nm after being annealed at 1000 °C for 3 h probably due to “sluggish diffusion effect”. The resultant HE spinel ferrites (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)Fe2O4 were first used as a heterogeneous catalyst of peroxodisulfate (PDS). Compared with basic solution condition, the HE spinel ferrite/PDS system exhibited a higher degradation rate for the removal of rhodamine B (RhB) and tetracycline (TC) at initial pH range of 3.0–5.1. Both the hydroxyl radicals and sulfate radicals played an important role on RhB and TC degradation. The high catalytic efficiency and good stability of high-entropy (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)Fe2O4 catalyst demonstrates that it is suitable for application in wastewater disposal.

Toward a comprehensive understanding of effect of cation distribution and M2+ constituent in spinel ferrite nanocrystals MFe2O4 (M = Co, Mn, and Ni) on the electrochemical response in sensitive detection of chloramphenicol

This paper focuses on investigating the effect of the (M2+) cation constituent and the inverse degree within the lattice structure of MFe2O4 (M = Co, Mn, and Ni) nanocrystals on their electrochemical characteristics and sensing performance under the same experimental condition. Using Rietveld refinement of powder X-ray diffraction (XRD), Raman, and scanning electron microscopy (SEM), physical characterizations of CoFe2O4 (CFO), MnFe2O4 (MFO), and NiFe2O4 (NFO) are observed and analyzed. In particular, a detailed study on current response and kinetic parameters for the electron transfer reactions in the presence of K3/K4 probes and chloramphenicol (CAP) analyte is carried out, respectively, highlighting the positive influence of the electrode modification and comparing the electrochemical characteristics and sensing performance. The ordering of their electrochemical performance is listed as follows: CFO/SPE> NFO/SPE> MFO/SPE. The reason for their electrochemical performance difference is discussed in detail. Namely, the CFO sample possessing high crystallization and phase purity, uniform primary particle size, and especially wholly inversed spinel structure possessing multiple valence states (Co2+ and Co3+) on the octahedral sites offered many unique features, which are beneficial for electrical conductivity, charge transferability, surface area, and electrocatalytic active sites. Despite also being the inversed spinel structure, the NFO with the existence of impurity phases and larger grain size, as well as a lower degree of inversion than the CFO sample showed a lower enhancement in electrochemical response. However, its electrochemical signal response still is higher than that of the normal spinel MFO structure, further confirming the critical role of (M2+) cation constituent and the inverse degree to the electrochemical characteristics and sensing performance.

Evolution of the Morphology and Magnetic Properties of Flaky FeSiAl/MFe2O4 (M = Mn, Co, Ni, Cu, Zn) Composites

Nanosized spinel ferrites MFe2O4 (M = Mn, Co, Ni, Cu, Zn)-coated flaky FeSiAl alloy composites were synthesized successfully. Nano-ferrites preferentially grow into nanoplatelets due to induced or restricted growth on the flaky surface of FeSiAl. With annealing temperature increasing, the ferrites' nanosheets thicken gradually and then grow into irregular particles. The annealing temperature not only affects the nanosized morphology and coating but also the magnetic properties of flaky FeSiAl composites. The saturation magnetization of CuFe2O4- or NiFe2O4-coated FeSiAl is approximate 69 emu/g, where the value of MnFe2O4-, CoFe2O4- and ZnFe2O4-coated FeSiAl show a decreasing trend generally from 64 emu/g to 55.7 emu/g annealing at 800 °C, respectively. The saturation magnetization of flaky FeSiAl composites was improved with the increased annealing temperature, except for those coated with ZnFe2O4 and NiFe2O4. These results are useful for improving the comprehensive properties of ferrite-coated flaky FeSiAl alloy composites.

Combustion-Synthesized CoFe2O4 Nanoparticles: Structure and electrical conductivity Studies

Nanocrystalline ferrites MFe2O4 (M = Ni, Co, Cu, Zn, Mn, Mg, etc.) are attracting the attention of researchers due to their utility in recording media, magneto-optics, spintronics, Ferrofluids, microwave devices, and so on. Ferrites are also utilized in gas and humidity sensors applications, anode material for a Li/Na-ion battery and electronic & magnetic applications. Combustion successfully generated cobalt ferrite (CoFe2O4) nanoparticles. X-ray diffraction (XRD) and infrared spectroscopy (FT-IR) were used to study the structural information. The crystallite size calculated by Scherer's formula is 14 nm based on XRD patterns. FTIR spectra indicate ferrite atoms in tetrahedral and octahedral positions, confirming the spinel phase. The electrical conductivity of CoFe2O4 nanoparticles at room temperature is 4.6 × 10-5 S cm−1.

Structural and Multiple Applicational Studies of Alkaline Earth Metal Spinel (AB2O4) Ferrites

The spinel ferrites MFe2O4 from alkaline earth metals (M = Mg, Ca, Sr, Ba) were identified as potential photocatalyst. The present work deals with the synthesis of mentioned ferrites by solution combustion synthesis using urea as fuel. X-ray pattern displays the formation of pure phase, whereas the functional groups were confirmed by FTIR studies. The UV-DRS spectra revealed that MgFe2O4 (2.3 eV) had an energy band gap that was optimal for visible light phototcatalytic degradation. The ferrites MgFe2O4, CaFe2O4, SrFe2O4 and BaFe2O4 displays excellent photocatalytic degradation performance for reactive blue 4 dye under visible light within 120 min resulted 93%, 84%, 92% and 79%, respectively. Compared to other synthesized ferrites SrFe2O4 shows remarkable specific capacitance with 288.7 × 10-3 F/g ascertains the super capacitor nature and also indicates better results to sense lead nitrate at very lower concentrations from cyclic voltammogram studies. The antibacterial activity against Bacillus and Pseudomonas (30 mg/mL) showed that CaFe2O4 was more effective than other synthesized ferrites.

Mercury remediation from wastewater through its spontaneous adsorption on non-functionalized inverse spinel magnetic ferrite nanoparticles

ABSTRACT In this study, inverse spinel cubic ferrites MFe2O4 (M = Fe2+, and Co2+) have been fabricated for the high-capacity adsorptive removal of Hg(II) ions. The PXRD analysis confirmed ferrites with the presence of residual NaCl. The surface area of Fe3O4 (Fe-F) and CoFe2O4 (Co-F) material was 69.1 and 45.2 m2 g−1, respectively. The Co-F and Fe-F showed the maximum Hg(II) adsorption capacity of 459 and 436 mg g−1 at pH 6. The kinetic and isotherms models suggested a spontaneous adsorption process involving chemical forces over the ferrite adsorbents. The Hg(II) adsorption process, probed by X-ray photoelectron spectroscopy (XPS), confirmed the interaction of Hg(II) ions with the surface hydroxyl groups via a complexation mechanism instead of proton exchange at pH 6 with the involvement of chloride ions. Thus, this study demonstrates a viable and cost-effective solution for the efficient remediation of Hg ions from wastewater using non-functionalized ferrite adsorbents. This study also systematically investigates the kinetics and isotherm mechanism of Hg(II) adsorption onto ferrites and reports one of the highest Hg(II) adsorption capacities among other ferrite-based adsorbents.

Effect of nanostructured ferrites MFe2O4 (M= Cu, Co, Mg, Zn) on the thermal decomposition of ammonium nitrate

Ammonium nitrate (NH4NO3) represents a cheap, chlorine-free alternative to ammonium perchlorate for use as an oxidant for solid propellants. But its poor ignitability and low burning rate are all disadvantages to achieve such purposes. For this reason, it is necessary to carry out studies to improve its combustion characteristics, seeking to combine it with catalysts or fuels. The present work explores the possibility of improving its combustion characteristics by adding ferrites as catalysts. Nanostructured ferrites MFe2O4 (M= Mg, Co, Cu, and Zn) synthesized by autocombustion method were tested as catalysts for the thermal decomposition reaction of ammonium nitrate under open, partially open or sealed conditions. The ferrites were characterized by XRD, SEM, UV-vis spectrophotometry and Mössbauer spectroscopy. All the MFe2O4 samples are single phased with a cubic spinel structure and average sizes, L, ranging from about 9 (CoFe2O4) to 25 nm (CuFe2O4). The catalytic effect of MFe2O4 on the thermal decomposition of NH4NO3 was investigated by thermogravimetric analysis and differential scanning calorimetry techniques. The process was also followed in a volumetric Sieverts type apparatus. The results indicate that only under sealed conditions the addition of these ferrites has influence in the decomposition process of AN. The incorporation of any of these ferrites decreases the onset temperature of the process manifested itself through an exothermic reaction, and also increases the amount of heat released in the reaction. The Co-ferrite showed the best efficiency causing the onset temperature to drop around 60 °C. The catalytic performance is correlated with the electronegativity of M2+ cations, which act as Lewis acid sites that interact with the gas molecules.

Size and Phase Purity–Dependent Microstructural and Magnetic Properties of Spinel Ferrite Nanoparticles

The urea-assisted combustion pathway was selected to synthesize different spinel ferrite nanoparticles (SFNPs). Synthesized spinel ferrite nanoparticles MFe2O4 (M = Zn, Ni, Cu and Co) were investigated using various techniques likely to be used by XRD, SEM, TEM and VSM to study their structural, morphological and magnetic behaviours. The crystalline sizes of the spinel ferrite nanoparticles were calculated from the major XRD peak (311) which confirms that the prepared spinel powders are in nanoscale (21–55 nm) range. Secondary peaks free XRD spectrum of Cu, and Ni ferrite nanoparticles exhibit pure single-phase cubic spinel structures. Few secondary impurities are observed in Zn and Co ferrite nanoparticles due to the presence of α-Fe2O3. Spherical-shaped nanoparticles have been examined by TEM. Room temperature magnetic measurements of different spinel ferrite nanoparticles suggest that the prepared spinel ferrites exhibit different forms of magnetism that are strongly affected by phase purity and particle size.

High-efficiency leaching of valuable metals from saprolite laterite ore using pickling waste liquor for synthesis of spinel-type ferrites MFe2O4 with excellent magnetic properties

High-efficiency leaching of valuable metals from nickeliferous laterite ore for preparation of functional materials is one of the most important high-value utilization pathways. In this paper, facile preparation of multi-metal spinel-type ferrites (MFe2O4) from saprolite laterite ore after pickling waste liquor leaching process was proposed. The effects of pickling waste liquor leaching parameters including acid concentration, leaching temperature and time, liquid–solid ratio and iron ion concentration on leaching efficiency for Fe, Ni, Mg, Mn and Co from saprolite laterite ore and the molar ratio (RFe/M) of iron ions to divalent metal ions such as Ni2+, Mn2+, Mg2+, etc. in the leach liquors were systematically investigated. After complete leaching, spinel-type ferrites were synthesized from leach liquors and the influence of RFe/M and pH value as well Zn ion doping on phase compositions, morphological structure and magnetic performance of as-synthesized samples were also characterized and analyzed. Under the optimized leaching conditions, the leaching efficiency of Ni, Co, Mn, Fe and Mg could reach 93.2%, 90.8%, 94.3%, 95.5% and 85.3%, respectively. With the concentration of iron ions in pickling waste liquors increasing from 60 to 160 g·L−1, the RFe/M value increases from 1.88 to 4.32. The pH values for synthesis of spinel-type ferrites with high purity from leach liquors with RFe/M of 1.85 and 2.04 are 8.0 and 11.0, respectively, and the saturation magnetization Ms values of as-synthesized ferrites increase gradually with the increasing of pH value. Zn ions in pickling waste liquors could be doped and fixed in spinel-type ferrites to improve Ms values of as-synthesized ferrites, and the Ms value could reach the highest as 58.6 emu·g−1 when Zn ions doping amount is 0.4. Value-added utilization of pickling waste liquor and saprolite laterite ore could be realized by the proposed process. This paper might provide theoretical and technical support for low-cost synthesis of spinel-type ferrites from polymetallic resources.

Earth abundant transition metal ferrite nanoparticles anchored ZnO nanorods as efficient and stable photoanodes for solar water splitting

Poor light absorption, severe surface charge recombination and fast degradation are the key challenges with ZnO nanostructures based electrodes for photoelectrochemical (PEC) water splitting. Here, this study attempts to design an efficient and durable nano-heterojunction photoelectrode by integrating earth abundant chemically stable transition metal spinel ferrites MFe2O4 (M = Co and Ni) nano-particles on ZnO Nanorod arrays. The low band gap magnetic ferrites improve the solar energy harvesting ability of the nano-heterojunction electrodes in ultraviolet–visible light region resulting in a maximum increase of 105% and 190% in photocurrent density and applied bias photon-to-current efficiency, respectively, compared to pristine ZnO nanorods. The favourable type-II band alignment at the ferrites/ZnO nano-heterojunction provides significantly enhanced photo-generated carrier separation and transfer, endowing the excellent solar H2 evolution ability (743 and 891 μmol cm−2 h−1for ZnO/CoFe2O4 and ZnO/NiFe2O4, respectively) of the photoanodes by using sacrificial agent. The hybrid nanostructures deliver long term stability of the electrode against photocorrosion. This work demonstrates an easy but effective strategy to develop low-cost earth abundant ferrites-based heterojunction electrodes, which offers excellent PEC activity and stability.

Cation Distribution in Monodispersed MFe2O4 (M = Mn, Fe, Co, Ni, and Zn) Nanoparticles Investigated by X-ray Absorption Fine Structure Spectroscopy: Implications for Magnetic Data Storage, Catalysts, Sensors, and Ferrofluids

Spinel ferrite MFe2O4 (M = Mn, Fe, Co, Ni, and Zn) nanoparticles, coordinated with oleylamine, oleic acid, and trioctylphosphine oxide, were effectively synthesized by the microwave-assisted rapid ...

Retraction Note to: Synthesis and magnetic characterization of Spinel ferrites MFe2O4 (M = Ni, Co, Zn and Cu) via chemical co-precipitation method

The Editor-in-Chief has retracted this article [1] because it substantially overlaps with the following articles (among others) [2,3]. [Author Abdelmajid Lassoued does not agree to this retraction and none of the other authors have responded to any correspondence from the editor or publisher about this retraction.]

Comparative study of frequency-dependent dielectric properties of ferrites MFe2O4 (M = Co, Mg, Cr and Mn) nanoparticles

Ferrites ‘MFe2O4 (M = Co, Mg, Cr and Mn)’ nanoparticles were successfully synthesized by chemical co-precipitation method. X-ray diffraction technique was used to determine the crystal structure, phase purity and average crystallite size of these ferrites nanoparticles. X-ray density and porosity were calculated by using standard relations. Sauter’s relation was also used to estimate the specific surface area of these nanoparticles. The important characteristics like morphology, size and shape of these nanoparticles were examined and estimated by scanning electron microscopy technique. The energy-dispersive X-ray spectroscopy was used to determine the elemental compositional of these ferrites nanoparticles. The vibrational modes and bond coordination among the various atoms of these ferrites nanoparticles were investigated by Fourier transform infrared spectroscopy. The frequency-dependent dielectric and impedance measurements were taken by LCR meter. The comparative analysis of dielectric parameters of these ferrites nanoparticles can help the audience to select the material having desired dielectric properties for energy storage practical applications especially lithium-ion batteries.

Influence of divalent metals (Zn, Cu and Co) on the synthesis and magnetic properties of spinel ferrite nanopowders

Hematite iron oxide (α-Fe2O3) and spinel ferrite nanopowders were synthesized by hydrothermal technique. The spinel ferrite MFe2O4 is prepared using three divalent metals M = Cu, Zn and Co. In order to investigate the spinel phase formation mechanism, we have used two atomic ratios (M/Fe) between Fe and divalent metal (above and below the stoichiometric ratio) and two preparation times (6 and 10 h). The nanopowder structure and morphology were characterized by mean of X-ray diffraction, scanning and transmission electron microscopies observation. The magnetic properties of the powder were archived using vibrating sample magnetometer. The results reveal that using low divalent metallic concentration yields to a powder composed of hematite and spinel phases. However, increasing the divalent metal concentration leads to the formation of monophasic spinel powder with a metallic oxide secondary phase. The spinel phase formation enthalpy controls the powder crystallite size and the secondary phase formation. The magnetic properties of the powder are altered by the presence of secondary phase. The magnetic exchange between the phase causes the surface spin canting resulting in the magnetic properties deterioration.

Synthesis of Spinel Ferrite MFe2O4 (M = Co, Cu, Mn, and Zn) for Persulfate Activation to Remove Aqueous Organics: Effects of M-Site Metal and Synthetic Method.

Metal species and synthetic method determine the characteristics of spinel ferrite MFe2O4. Herein, a series of MFe2O4 (M = Co, Cu, Mn, Zn) were synthesized to investigate the effect of M-site metal on persulfate activation for the removal of organics from aqueous solution. Results showed that M-site metal of MFe2O4 significantly influenced the catalytic persulfate oxidation of organics. The efficiency of the removal of organics using different MFe2O4 + persulfate systems followed the order of CuFe2O4 > CoFe2O4 > MnFe2O4 > ZnFe2O4. Temperature-programmed oxidation and cyclic voltammetry analyses indicated that M-site metal affected the catalyst reducibility, reversibility of M2+/M3+ redox couple, and electron transfer, and the strengths of these capacities were consistent with the catalytic performance. Besides, it was found that surface hydroxyl group was not the main factor affecting the reactivity of MFe2O4 in persulfate solution. Moreover, synthetic methods (sol–gel, solvothermal, and coprecipitation) for MFe2O4 were further compared. Characterization showed that sol–gel induced good purity, porous structure, large surface area, and favorable element chemical states for ferrite. Consequently, the as-synthesized CuFe2O4 showed better catalytic performance in the removal of organics (96.8% for acid orange 7 and 62.7% for diclofenac) along with good reusability compared with those obtained by solvothermal and coprecipitation routes. This work provides a deeper understanding of spinel ferrite MFe2O4 synthesis and persulfate activation.

Photoelectrochemistry of Ferrites: Theoretical Predictions vs. Experimental Results

AbstractThis paper gives an overview about recent theoretical and experimental work on electronic and optical properties of spinel ferritesMFe2O4. These compounds have come into focus of research due to their possible application as photocatalyst material for photoelectrochemical water splitting. The theoretical background of state-of-the-art quantum-chemical approaches applied for predicting electronic and optical band gaps, absolute band positions, optical absorption spectra, dielectric functions and Raman spectra, is briefly reviewed. Recent applications of first-principles methods on magnetic and electronic properties of ferrites withM= Mg and the first row of subgroup elements Sc to Zn are presented, where it is shown that the fundamental band gap is strongly dependent on the spin state and the degree of inversion of the spinel structure. The observed variation of electronic properties may serve as an explanation for the large scattering of experimental results. The exchange ofMand Fe cations has also a pronounced effect on the Raman spectra of ferrites, which is analyzed at atomic scale from first principles. Calculated optical absorption spectra of ferrites are compared to experimental spectra. The electronic nature of the first excitations and the role of oxygen vacancies are discussed. For the calculation of absolute band positions, which have a significant impact on the photoelectrochemical activity of the ferrites, models of the most stable ferrite surfaces are developed that take into account their polar nature and the interaction with the solvent. Theoretically predicted valence and conduction band edges are compared to results from electrochemical measurements. The role of cation exchange on the surface electronic structure is investigated both theoretically and experimentally.

Synthesis of Active MFe2O4/γ-Fe2O3 Nanocomposites (Metal = Ni or Co) for Reduction of Nitro-Containing Pollutants and Methyl Orange Degradation

Metal-ferrite/maghemite nanocomposites (NiFe2O4/***[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O[Formula: see text] were synthesized via doping maghemite with metal salt (NiCl2 or CoCl[Formula: see text] followed by reduction of metal ions using NaBH4. The synthesized metal-ferrite/maghemite nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) and the amounts of the dopant-metal (Ni/Co) were determined using ICP-OES technique. Results showed that this synthetic route produced nanocomposites with highly active ferrite phases MFe2O4. The synthesized nanocomposites exhibited exceptional catalytic activities for the reduction of 4-nitrophenol and 2-nitroaniline as well as the catalytic degradation of methyl orange. Specific activity parameter of NiFe2O4/[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O3 toward reduction of 4-NP reached 993.9 and 929.8[Formula: see text]s[Formula: see text][Formula: see text]g[Formula: see text], respectively. These high values of specific activities are higher than most reported metal-ferrite composites prepared via traditional co-precipitation methods. Besides, strong magnetic properties of the prepared metal-ferrite/maghemites facilitates easy separation process for several reuses.