Manganese Ferrite Research Articles

Fabrication of MnFe2O4 and Ni: MnFe2O4 nanoparticles for ammonia gas sensor application

Manganese ferrites (MnFe2O4) and three different weight percentage of nickel doped manganese ferrites (Ni: MnFe2O4) was prepared through a chemical co-precipitation method. The crystal structure, crystallite size, and phase of the prepared materials are determined by X-Ray Diffraction technique (XRD). The average crystallite size was calculated to be 44 nm, 42 nm, 37 nm, and 35 nm for MnFe2O4, Ni1%Mn(x−1%) Fe2O4, Ni3%Mn(x−3%)Fe2O4, and Ni5%Mn(x−5%)Fe2O4, respectively. Fourier Transforms Infrared (FTIR) spectroscopy technique is used to study the functional groups present in the prepared materials. Surface morphology and elemental compositions of the synthesized nanoparticles were examined using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDAX). The gas sensing property of the prepared materials was studied with different ppm of ammonia gas (NH3), and the respective response and recovery time was calculated.

Enhanced sunlight driven photocatalytic activity and electrochemical sensing properties of Ce-doped MnFe2O4 nano magnetic ferrites

This research deals with the facile combustion synthesis of manganese ferrite (MFO) nanoparticle with different cerium concentration and their potential application as an efficient photocatalyst and chemical sensor. The concentration of introduced cerium affects the size, structure, compositional, morphological, optical, photoluminescence and magnetic properties of the ferrite nanoparticle. The X-ray diffraction pattern affirmed the arrangement of cubic spinel structure with the formation of secondary phase CeO2 as the cerium concentration exceed 3 mol%. SEM micrographs revealed irregular morphology with more number of pores and voids. HRTEM along with SAED pattern revealed the crystalline cubic nature. The optical band gap deduced from UV–Vis-DRS spectra was observed to be in the range 2.3–2.8 eV. PL studies indicated a significant minimization in combination of electrons & holes in MnFe2O4 on addition of Ce dopant. VSM investigation demonstrated the soft magnetic nature of the prepared sample with moderate magnetization value. An excellent photocatalytic performance of Cerium doped MFO (3 mol%) towards MB and AR dye degradation was found to be 1.5 and 1.67 times more compared to host matrix under Sunlight irradiation that correlated to reduced band gap, Ce dopant and efficient separation of charge carriers. Cerium doped MFO (3 mol%) have high specific capacitance value of 471.7 and 1546.8 Fg-1 for NaNO3 and HCl electrolytes respectively, indicating the pseudo capacitance nature due to which it can be used as a supercapacitor. The synthesized nanoparticles can sense d-Glucose and Paracetamol even at a lower concentration varying from 1 to 10 mM. The synthesized Ce-doped MnFe2O4 nanomaterials have great potential to be used in the future production of promising active photocatalysts and sensitive chemical sensors for the identification and degradation of toxic industrial dyes for improved safety in the fields of environment and health care.

Influence of the heat treatment conditions on the properties of gallium-strontium-substituted manganese ferrites designed for magnetic hyperthermia applications

Magnetic nanoparticles (MNPs) with cores made of mixed ferrites may find application in the field of magnetic hyperthermia, this due to their intrinsic characteristics such as nanometric sizes, biocompatibility and the capability of transforming mechanical energy into heat under the action of an external magnetic field. In this study, the synthesis of Mn, Ga and Sr-containing ferrites (Mn0.5Ga0.5-xSrxFe2O4, x = 0.05 and 0.1) via sol-gel was carried out evaluating the effect of the heat treatment conditions on the physicochemical properties. The obtained materials were characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Additionally, the heating ability of the obtained nanoparticles was evaluated by magnetic induction and an in vitro hemolysis assay was also performed. Within the tested heat treatment conditions (150–600 °C and 30–120 min) it was possible to obtain nanosized magnetic ferrites with a single crystalline phase, corresponding to the cubic inverse spinel structure, and with a behavior close to the superparamagnetic regime. Moreover, selected materials showed heating ability under the application of a magnetic field and were non-hemolytic in contact with human blood red cells, making them suitable for their use as heating agents for the magnetic hyperthermia treatment.

Manganese ferrite modified biochar from vinasse for enhanced adsorption of levofloxacin: Effects and mechanisms.

The primitive biochar (BC) and NiFe2O4/biochar composites (NFBC), biological adsorbents prepared from vinasse wastes, possess the environmental application in levofloxacin (LEV) removal. In this study, the efficient adsorption of LEV onto biochar synthesized by pyrolysis of vinasse wastes from aqueous environment was investigated. The influencing factors (i.e., pH, reaction time, and temperature) of adsorption process were also well studied. The results indicated that the maximum adsorption capacities of both BC and NFBC were occurred in mildly acidic condition (pH 6). In addition, the biochar adsorption capacities were obviously increased in higher temperature (25-45°C). The chemistry adsorption and monolayer homogeneous dominated adsorption process of LEV onto BC and NFBC. The adsorption process was spontaneous and endothermic by thermodynamic analysis. The SEDA (site energy distribution analysis) explained that the adsorption effectivity increased by increasing site energy of biochar surface. The SEDA revealed the more energy heterogeneity in NFBC, fitting the characterization result of Fourier-transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The electron-donor-acceptor (EDA) interactions and hydrogen bonds is suggested as the major adsorption mechanism. And as for the adsorption of the various biowaste recycled synthetic, this study can be referred in discussion of performance analysis and optimal condition.

Synthesis of manganese doped β-FeOOH and MnFe2O4 nanorods for enhanced drug delivery and hyperthermia application.

Preparation of manganese ferrite (MnFe2O4) nanorods by the reduction of akaganeite seeds in the presence of oleylamine is reported. The Mn-doped β-FeOOH akaganeite seeds have been processed by the hydrolysis of metal-chloride salts in the presence of polyethylenimine (PEI) surfactant. The hydrophobic oleylamine capped nanorods are made hydrophilic using trisodium citrate as a phase transferring agent. The nanorods form with an aspect ratio of 5.47 and possess a high magnetisation value of 69 emu/g at an applied magnetic field of 1.5 T. The colloidal water dispersion of nanorods exhibits superior heating efficiency by the application of alternating magnetic field (AMF). A specific absorption rate value of 798 W/g is achieved at an applied AMF of field strength 500 Oe and frequency 316 kHz. Further, the citrate functionalised nanorods are capable of attaching with doxorubicin (DOX) electrostatically with a loading efficiency of 97% and the drug release is pH responsive. The DOX loaded nanorods show a promising effect on the apoptosis of MCF-7 as experimented in vitro.

Innovative methodology for co-treatment of mill scale scrap and manganese ore via oxidization roasting-magnetic separation for preparation of ferrite materials

Mill scale scrap, which contains vast amounts of valuable metals, is a solid waste produced in the iron and steel industry. Conventional mill scale scrap treatment methods for metal extraction are characterized by high energy consumption and low value addition. In this study, co-treatment of mill scale scrap and manganese ore via the oxidization roasting-magnetic separation process was investigated for the synchronous preparation of higher-value materials and recovery of valuable metals. Thermodynamic and magnetism analyses indicated that a higher temperature (>1100 °C) and a MnO2/Fe2O3 molar ratio of 0.75–1 are essential for the preparation of manganese ferrite. The experimental validation revealed that soft magnetic manganese ferrite powders with a purity of 97.5 wt% were obtained when the test was conducted at 1300 °C for 120 min, followed by a two-stage grinding and magnetic separation process; the corresponding yield and the Mn and Fe recoveries were 78.99 wt%, 86.14 wt%, and 84.60 wt%, respectively. During the oxidization process, [Fe2+]O was initially oxidized to the anti-form spinel-type structure of [Fe3+][Fe2+Fe3+]O4, and thereafter, it reacted with the decomposition product of [Mn3+][Mn2+Mn3+]O4 to form a hybrid spinel-type structure [Me2+xMe3+l-x][Me2+1-xMe3+1+x]O4 (Me refers to Mn and Fe) via the Mn2+/Fe2+/Mn3+/Fe3+ ions exchange at the tetrahedral and octahedral sites. Moreover, the as-purified ferrite can be used as an ingredient for the preparation of high-performance MnZn ferrite.

Ferrite‐based room temperature negative temperature coefficient printed thermistors

Two screen printing inks were developed for the low-temperature fabrication of printed and flexible thick film negative temperature coefficient (NTC) thermistors able to operate at room temperature. The first of the two screen printing inks developed utilised cobalt ferrite (CoFe2O4) as the temperature sensing material with the second ink incorporating manganese ferrite (MnFe2O4). These were then screen printed onto lithographically printed silver interdigitated electrodes with a 200-micron track and gap using a synthetic paper (Teslin) as the substrate. The inks required a 10-minute curing step at 80oC. Preannealing of the ferrite powders before ink formulation enabled the avoidance of high-temperature processing post-fabrication typically required in industrial thermistor production. The printed thermistors were tested at a controlled constant humidity between 15 and 50oC. Both materials demonstrated typical natural logarithmic responses with high linearity and sensitivity.

Synthesis, characterization, and lead (II) sorption performance of a new magnetic separable composite: MnFe2O4@wild plants-derived biochar

In present study, the magnetic separable biochar nacomposite (MWPC) was synthesized by using the facile chemical coprecipitation method of wild plants-derived biochar (WPC) and manganese ferrite nanoparticles (MnFe2O4). Its crystal structure, surface morphology and elemental composition, textural structure, surface chemistry and magnetic performance were illuminated. The magnetic nanoparticles of spinel manganese ferrite were observed to significantly affect the surface area and pore structure of the WPC. Its saturation magnetization value was measured as 19.7 emu/g. In addition, the optimum sorption conditions of the lead selected as a model for testing metal sorption performance from water were determined by considering the effects of important process parameters such as solution pH, metal concentration, interaction time and temperature. The kinetic and isotherm sorption data were found to be well compatible with Langmuir isotherm and pseudo-second order kinetic models, respectively. It was observed that the maximum Pb(II) sorption capacity of MWPC was approximately 2.6 times higher than that of WPC. Thermodynamic parameters such as ΔG°, ΔH°, ΔS° calculated to explain the nature of the interaction during the sorption showed that the process is endothermic and spontaneous. The findings show that MWPC has a high surface area and a wide porous sorbent that is effective in lead removal and can be magnetically separated without leaving a second pollution to the environment.

The effect of MnxCo(1-x)Fe2O4 with x = 0, 0.25 and 0.5 as nanoparticles additives in magnethorheological fluid

This study focused on the effect of manganese substituted cobalt ferrite (Mn x Co1–x Fe2O4) nanoparticles with different mole ratios (x = 0, 0.25 and 0.5) in magnetorheological fluids (MRF). The nanoparticles were synthesized using co-precipitation method. The irregularly–spherical form of the nanoparticles was observed/confirmed using a field emission scanning (FESEM) microscope. The vibrating sample magnetometer (VSM) was performed to analyze the effect of nanoparticles in MRF on their magnetic properties. The VSM test results show that the nanoparticles have a negative effect on the magnetic properties of MRF. The higher magnetic saturation of nanoparticles will reduce more magnetic saturation in MRF. This phenomenon shows that the direction of the magnetic field from the cobalt manganese ferrite has the opposite direction to MRF. It is also identified that the field-dependent rheological properties of MRF show that the addition of nanoparticles increases the yield stress of MRF results except for Mn0.5Co0.5Fe2O4 which leads to the reduction of the yield stress of MRF.

Synthesis of amine imprinted manganese ferrite and its application in the removal of free fatty acid from waste vegetable oil

The presence of free fatty acid (FFA) in waste vegetable oil (WVO) is undesired and must be removed. The present study synthesized amine imprinted manganese ferrite (MnFe2O4-DEA) via coprecipitation method and used it for the removal of FFA in WVO. Fourier transformed Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirmed the formation of MnFe2O4-DEA and further analysis by Brunauer-Emmett-Teller (BET) surface area showed the nanoparticles possessed a surface area of 20.64 m² g−1. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) revealed elemental composition and surface morphology. MnFe2O4-DEA showed promising results of FFA separation, recording 99.57% removal rate. The process obeyed langmuir isotherm and can be described by pseudo-second-order kinetic model. The values of Gibb's free energy change (∆Go) decreased with increase in temperature, the entropy change (∆So) was positive while enthalpy change (∆Ho) value suggested an endothermic sorption process. The mechanism for the removal of FFA by MnFe2O4-DEA may have occurred by simple chemical bonding, which could be described as donor-acceptor interaction by quantum chemical analysis.

Reaction performance and lattice oxygen migration of MnFe2O4 oxygen carrier in methane-carbon dioxide reaction system

Chemical looping partial oxidation of methane (CLPOM) coupled with carbon dioxide splitting process was proposed in this work to achieve high H2/CO ratio syngas and CO production simultaneously. Manganese ferrite (MnFe2O4) oxygen carrier with a spinel structure was prepared by using a co-precipitation phase inversion method for this methane-carbon dioxide reaction system. The reaction performance of oxygen carrier was investigated in fixed bed reactor combined with the analytical methods of XRD, TPR, H2-TG and XPS. The results revel that spinel structure MnFe2O4was successfully prepared and Fe is the main active spices to release lattice oxygen. TG analysis confirms that 43.3% of lattice oxygen can release from MnFe2O4 in H2 atmosphere with highest release rate 0.4%/min at 721 °C. The maximum conversion of CH4 and CO2 are 63% and 99% achieved in CLPOM coupled with CO2 splitting process and temperature makes a positive effect on the reaction process. Moreover, the reaction stability of MnFe2O4 oxygen carrier are verified in 10 cycles reaction of CLPOM coupled with CO2 splitting with the reaction path MnFe2O4→(FeO)0.798-(MnO)0·202/FeO →MnFe2O4. Moreover, The MnFe2O4 oxygen carriers with different reduction stages were analyzed by XPS to reveal lattice oxygen migration mechanism, which indicates that the bulk lattice oxygen of oxygen carrier gradually dissociated and migrated to the outer surface in reaction process where reacts directly with methane or converts to oxygen adsorption OII. The valence of Mn has not changed in the whole reaction process, whereas, Mn species forms the synergistic effect with Fe to improve the conversion of CH4 and CO2, promoting the oxidization of Fe2+ to Fe3+ in CO2 atmosphere. MnFe2O4 oxygen carrier is a promising candidate for the CLPOM coupled with CO2 splitting process.

Effects of synthesis conditions on structure and magnetic properties of MnFe2O4particles

Manganese ferrite (MnFe2O4) nanoparticles were synthesized through a coprecipitation method using manganese (II) chloride tetrahydrate (MnCl2·4H2O) and ferric chloride hexahydrate (FeCl3·6H2O) as precursors. The scanning electron microscopy images showed that the as-synthesized particles were granular and about 20 nm. The X-ray diffraction patterns revealed that the manganese ferrite phase was completely decomposed into ferric oxide (Fe2O3) and manganese (III) oxide (Mn2O3) after annealing above 800°C in air. In contrast, its crystalline quality significantly improved when it was annealed in argon. By using the vibrating-sample magnetometry technique, it was demonstrated that the saturation magnetization (Ms) of the as-prepared sample (~36.6 emu/g) decreased sharply up to ~5 emu/g after annealing at 1000°C in air and significantly increased to ~77.6 emu/g when it was annealed at 1000°C in argon. Under sunlight radiation, a higher efficiency was observed for manganese ferrite particles annealed in argon in the presence of hydrogen peroxide (H2O2), mainly due to the Fenton reaction between manganese ferrite and hydrogen peroxide. The authors suggest that the presence of hydrogen peroxide and the enhancement of the crystalline quality of the manganese ferrite phase are the two leading factors in improving methylene blue degradation efficiency.

Superparamagnetic Manganese Ferrite and Strontium Bioactive Glass Nanocomposites: Enhanced Biocompatibility and Antimicrobial Properties for Hyperthermia Application

Herein, the strontium bioactive glass with ferrite composites is studied for the application of biocompatibility and magnetic hyperthermia. The bioactive glass SrBG (46.1SiO2–21.9CaO–24.4Na2O–2.6P2O5–5SrO) prepared by the melt quench technique at 1400 °C and manganese ferrite (MnFe2O4) prepared by the modified microwave reflux oven are mixed together and sintered at 400 °C for 6 h for making composites. The in vitro bioactivity of these composites is observed by immersing in simulated body fluid (SBF). The growth of the precipitated hydroxyapatite phase observed after SBF treatment is confirmed by the X‐ray diffractometer (XRD), Fourier transform infrared (FTIR) spectrometer, and scanning electron microscope (SEM) results. The in vitro cell viability assessment of these composites with MG‐63 cell lines indicates that the composites are biocompatible in nature. Furthermore, these composites show the antibacterial effect on the E. coli and S. Aureus bacteria cells. The room temperature superparamagnetic behavior accompanied by the heating ability in these composites proves their potential role for hyperthermia applications.

Comparative study of enzymatic and non-enzymatic detection of glucose using manganese ferrite nanoparticles

The use of metal oxide nanoparticles for the development of cost-effective glucose biosensors has been receiving increased attention. Enzymatic and non-enzymatic glucose sensor using polyethylene glycol (PEG) grafted manganese ferrite (PEG-MnFe2O4) nanoparticles (NPs) modified onto a glassy carbon electrode (GCE) is reported in the present study. XRD and Raman studies confirmed the cubic spinel structure of MnFe2O4. The immobilization of glucose oxidase (GOx) on PEG-MnFe2O4 (GOx@PEG-MnFe2O4) was validated using FTIR and TGA. Sensing electrodes exhibited well-defined redox peaks in 0.1 M phosphate buffered saline (PBS) solution at pH 7.4 against the reference electrode Ag/AgCl. GOx@PEG-MnFe2O4/GCE displayed a sensitivity of 1.985 μA mM−1 cm−2 in the linear range of 1 to 20 mM with a limit of detection (LOD) of 0.132 mM whereas non-enzymatic sensor exhibited a sensitivity of 1.044 μA mM−1 cm−2 in the linear range of 1 to 10 mM with a LOD of 0.099 mM. The lower Michaelis constant () value indicates greater affinity towards glucose for the enzymatic sensor. GOx@PEG-MnFe2O4 revealed selectivity specifically for glucose over various interferants such as fructose, lactic acid, sucrose, uric acid and ascorbic acid. In addition, this enzymatic sensor demonstrated better reproducibility and lifetime.

The investigation of structural and magnetic properties of MnFe2−xWxO4 nanoparticles

The investigation of effective synthesis routes and applications of magnetic nanomaterials are of great importance in recent years. Here in this article, W3+ substituted manganese ferrite (MnFe2−xWxO4) nano particles were prepared via cost effective and a new micro emulsion strategy. The synthesized materials were first characterized by different physicochemical analyzing techniques to study the structural, spectral and magnetic properties in detail. From the XRD investigation, a cubic phase was observed in all samples of Tungsten substituted Manganese ferrites with a very minute secondary phase. Variation in lattice parameters and observed peak shifting in substituted samples directed towards introduction of tungsten ions in the spinel MnFe2O4. The change in band positions (ν1 and ν2) also suggested the incorporation of foreign impurity (W3+) in spinel lattice. From the magnetic measurement investigation, a significant rise in saturation magnetization (Ms) and coercivity (Hc) was observed. In this regard, the excellent properties and the soft magnetic behavior and of this new tungsten substituted manganese ferrite (MnFe2−xWxO4) suggested its effective utilization in sensors, switching, multilayer chip inductor and many advance technological applications.

MnFe2O4 nanoparticles anchored on the surface of MgAl-layered double hydroxide nanoplates for stable magnetorheological fluids

In the present study, the manganese ferrite (MnFe2O4) nanoparticles were controllably anchored on the surface of MgAl-layered double hydroxide (MgAl-LDH) using a facile two-step hydrothermal method, and the as-prepared MnFe2O4/MgAl-LDH nanocomposites were adopted as the magnetic dispersed phase to prepare a stable and uniform magnetorheological (MR) suspension. The obtained MnFe2O4/MgAl-LDH nanocomposites were deeply characterized by XRD, TEM, XPS, BET and SQUID, and the viscoelastic properties of MnFe2O4/MgAl-LDH based MR fluid were investigated in detail under the action of different magnetic fields. More importantly, the results of sedimentation tests showed that the sedimentation stability of MnFe2O4/MgAl-LDH based MR fluid was much higher than that of carbonyl iron (CI) particles based MR fluid. The improved sedimentation stability can be attributed to the special plate-like structure, high specific surface area and reduced density difference.

Structural, morphological, luminescence, magnetic, and electrical transport properties of zinc-doped MnFe2O4 nanomaterials

From citrate gel autocombustion method, Zn-substituted manganese ferrites, Mn1−xZnxFe2O4 (X = 0.0–1.0), have been fabricated. XRD studies exhibit cubic spinel structure with single phase, and there is no impurity with crystalline size which is 11–30 nm regions. From SEM, surface morphology revealed uniform of cubic face particles with some agglomerations. All the elemental ions are present in synthesized samples according to stoichiometric ration which were confirmed by EDS. The TEM studies confirmed the particle size and morphology of samples synthesized. Optical studies performed by UV–DRS spectroscopy showed a peak at 475 nm that shifts and to lower wavelength with increasing Zn concentration in samples. Luminescence properties were studied by photoluminescence spectroscopy. The stretching frequencies of prepared samples were confirmed by FTIR spectroscopy. Magnetic properties of the synthesized materials were investigated from VSM at room temperature and as well as low-temperature field cooled and zero field cooled. The dielectric parameters dielectric constant $$ \varepsilon ' $$ and dielectric loss tangent (tan δ) decreased with increasing frequency showing a normal ferrite behavior. The temperature-dependent dielectric studies showed a decrease in $$ \varepsilon ' $$ with an increasing temperature and Zn substitution. The variation in AC conductivity (σac) is due to polarons. The EIS of the sample revealed that the conductivity is mainly due to grain boundaries. The Cole–Cole impedance plots show semicircular behavior. Dielectric dispersion observed due to interfacial polarization of Maxwell–Wagner type. Dielectric loss tangent has been decreased with the increase of applied frequency.

Recovery of nanoferrites from metal bearing wastes: Synthesis, characterization and adsorption study

Manganese ferrite (MnFe2O4) nanoparticles were produced by surfactant-assisted method using as metal sources both synthetic chemicals and industrial wastes (spent Li-ion batteries and pyrite ash) and performing different thermal treatments (microwave, autoclave, furnace at different temperature, oven).Nanoferrites obtained using synthetic precursor by microwave-surfactant assisted hydrothermal route showed distinct XRD peak of spinel phase; nanoparticles were characterized by SEM, BET, magnetism and adsorption tests. Nanoferrites were found to have plate shape with 715 nm width size, 5.23 emu/g, 57 ± 1 m2/g surface size, 0.59 ± 0.03 mmol/g arsenic and 0.80 ± 0.04 mmol/g copper adsorption capacity.Thermal treatment performed during synthesis by microwaves gave the best results in terms of crystallinity, surface area, magnetism and metals sorption capacity. In particular, the ideal nanoparticles were found to have octahedron shape with 22.3 nm size, 38.63 emu/g magnetism, 159 ± 1 m2/g surface size, 0.63 ± 0.03 mmol/g As(V) and 1.17 ± 0.05 mmol/g Cu(II) adsorption capacity.Then experimental findings showed that using the same optimized conditions (microwave assisted hydrothermal route) waste precursors gave nanoferrites with different morphology, similar mineralogical phase, and improved characteristics in terms of magnetic properties, surface area and metal sorption capacity.

Green sonochemical synthesis and fabrication of cubic MnFe2O4 electrocatalyst decorated carbon nitride nanohybrid for neurotransmitter detection in serum samples

The binary nanomaterials and graphitic carbon based hybrid has been developed as an important porous nanomaterial for fabricating electrode with applications in non-enzymatic (bio) sensors. We report a fast synthesis of bimetal oxide particles of nano-sized manganese ferrite (MnFe2O4) decorated on graphitic carbon nitride (GCN) via a high-intensity ultrasonic irradiation method for C (30 kHz and 70 W/cm2). The nanocomposites were analyzed by powder X-ray diffraction, XPS, EDS, TEM to ascertain the effects of synthesis parameters on structure, and morphology. The MnFe2O4/GCN modified electrode demonstrated superior electrocatalytic activity toward the neurotransmitter (5-hydroxytryptamine) detection with a high peak intensity at +0.21 V. The appealing application of the MnFe2O4/GCN/GCE as neurotransmitter sensors is presented and a possible sensing mechanism is analyzed. The constructed electrochemical sensor for the detection of 5-hydroxytryptamine (STN) showed a wide working range (0.1–522.6 μM), high sensitivity (19.377 μA μM−1 cm−2), and nano-molar detection limit (3.1 nM). Moreover, it is worth noting that the MnFe2O4/GCN not only enhanced activity and also promoted the electron transfer rate towards STN detection. The proposed sensor was analyzed for its real-time applications to the detection of STN in rat brain serum, and human blood serum in good satisfactory results was obtained. The results showed promising reproducibility, repeatability, and high stability for neurotransmitter detection in biological samples.

Sonochemical synthesis of MnFe2O4 nanoparticles and their electrochemical and photocatalytic properties

In this study, the electrochemical characteristics of manganese ferrite (MnFe2O4) nanoparticles were assessed using various electrochemical techniques, including cyclic voltammetry (CV), galvanostatic charge–discharge analysis, and electrochemical impedance spectroscopy. The electrode material comprising MnFe2O4 nanoparticles with a nanorod spinel structure was synthesized via the sonochemical route and the dimensions in of the nanoparticles ranged from 16 to 24 nm. X-ray diffraction, Fourier transform-infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and diffuse reflectance spectroscopy were used to determine the characteristics of the MnFe2O4 nanoparticles. HCl and NaOH were used as electrolytes to study the electrochemical behavior of the nanoparticles. The specific capacitance values determined from the CV curves obtained using the MnFe2O4 versus Ag/AgCl electrodes at an AC amplitude of 5 mV and in the frequency range from 1 Hz to 1 MHz in acidic and basic electrolytes with concentrations of 0.1 M were 4.2566 F g−1 and 2.2099 F g−1, respectively. The application of MnFe2O4 as a photocatalyst under ultraviolet light degraded the dyes comprising methylene blue and Drimaren yellow by up to 96% and 7%, respectively. The results obtained in this study verified the potential applications of sonochemically synthesized MnFe2O4 in semiconductors, sensors, and energy storage devices.