NiFe2O4 Research Articles

Probing the p-type Chemiresistive Response of NiFe2 O4 Nanoparticles for Potential Utilization as Ethanol Sensor.

Detection of gas molecules and volatile organic compounds (VOCs) using efficient, low cost sensors has fetched significant attention in environmental monitoring, safety measures and medical diagnosis. In the present work, nickel ferrite (NFO) nanoparticles are explored as p-type semiconducting metal oxide (SMO) sensor for detection of five different organic vapors namely methanol, ethanol, n-propanol, iso-propanol and acetone which often cause severe damage to human body under prolonged exposure. The sensing studies in presence of the aforementioned five vapors are carried out by varying the sensor operating temperature (225-300 °C) and vapor concentrations (10-1000 ppm). Developed NFO sensor demonstrated best performance in terms of sensing (~10 ppm), response time (<10 s), excellent repeatability and selectivity towards ethanol among all other considered gas species. The repeatability of the sensor response is verified and the underlying reasons for the variation in the response of NFO sensor due to the change of operating temperature, analyte type and concentrations has been discussed. The synthesis of NFO through auto combustion method and study on their formation behaviour, oxygen vacancy evolution, band gap calculation, crystalline nature as well as microstructural features provides here the comprehensive information about the potential application of NFO nanoparticles as gas sensor.

1D mesoporous NiFe2O4 nanorods fabricated by electrospinning for efficient oxygen evolution reaction

Designing and preparing efficient and stable oxygen evolution reaction (OER) catalysts is crucial to improve water splitting performance. One-dimensional (1D) structural catalysts have received increasing attention for the OER due to their unique structural characteristics. In this study, 1D mesoporous NiFe2O4 (NFO) spinel nanorods are fabricated by electrospinning, and the differences in physical structure and electrochemical performance of NFO nanorods prepared by different electrospinning precursors are investigated. It is found that the NFO nanorods prepared by precursor of nickel-iron hydroxide particles (denoted as NFOH) exhibit a diameter of approximately 200 nm and a surface area of 26.4 m2 g−1. In 1 M KOH solution, NFOH nanorods achieve low overpotentials of respective 316 mV and 396 mV to obtain current densities of 10 mA cm−2 and 50 mA cm−2, as well as a low Tafel slope of 67.2 mV dec−1, even lower than commercial NFO. Notably, the nanorods also demonstrate excellent long-term stability. The high OER activity can be attributed to the small nanoparticle size, abundant electrochemical active sites provided by the 1D mesoporous nanostructure, and increased conductivity, which promote charge/electron transfer and enhance the conversion of active species, thereby improving the efficiency of water electrolysis. This work may broaden the perspective and approach for the structural design of OER catalysts.

Electrical and magnetic properties of MF/CuAl nanocomposites

Abstract This study investigated the effects of CuAl2O4 (CuAl) on four types of spinel ferrites: CoFe2O4 (CoF), NiFe2O4 (NiF), MgFe2O4 (MgF), and ZnFe2O4 (ZnF) with regards to their electrical characteristics and microscopic magnetic behavior. According to the Seebeck coefficient (φ), the nanocomposites have a mixture of positive and negative charge carriers, except for CoF/CuAl, which has a positive charge carrier only. Depending on the temperature, the DC conductivity of all MF/CuAl nanocomposites has a conductor and semiconductor behavior. The dielectric properties were studied at different frequencies (100–10^8 Hz) and temperatures (300–673 K). The results demonstrated how temperature and frequency affect AC operating mechanisms. The high values of dielectric loss for all nanocomposites confirm their applicability in high-frequency microwave devices. The impedance study revealed that the equivalent circuit for all MF/CuAl nanocomposites is a mixture of R, L, and C. Temperature-magnetization graphs were obtained for all nanocomposites, indicating ferrimagnetic behavior except ZnF/CuAl. The magnetic transition temperature (T Cm), the Curie–Weiss constant (θ CW), and the effective magnetic moments (μ eff) for all nanocomposites were determined. The MF/CuAl samples were analyzed using ESR spectroscopy at room temperature. The spectra were distorted but remained distinct, potent, and sweeping. The g-factor values deviate from the free electron, which suggests that the Fe3+–O–Fe3+ superexchange interaction has changed. In addition, the interaction effect between MF and CuAl is discussed.

Degradability of methylene orange synthetic dyes of multiferroic NiFe2O4–Ba0.8Sr0.2TiO3 composites

Five samples of xNiFe2O4/(1 − x)Ba0.8Sr0.2TiO3 (where x = 0, 0.1, 0.2, 0.3, and 0.4) multiferroic nanocomposites have been successfully fabricated using ball milling combined with heat treatment in a short time. X-ray diffraction patterns indicated the coexistence of two phases, namely, NiFe2O4 (NFO) and Ba0.8Sr0.2TiO3 (BSTO). The average grain size obtained is about 50–100 nm, and NFO and BSTO phases are evenly distributed in the samples. With an increase in the content of NFO, the values characterizing the ferroelectric and ferromagnetic properties improve significantly. Furthermore, the bandgap energy (Eg) value was also strongly reduced. The results on the degradability of methylene orange show that the apparent first-order rate of composites containing NFO with x = 0.4 was found to be k = 0.0228 min−1, which is significantly higher than that of pure BSTO (k = 0.0166 min−1), suggesting that NFO/BSTO multiferroic nanocomposites could be considered as candidate photocatalysts for the degradation of pollutants.

Design and preparation of novel LaFeO3/NiFe2O4 nanohybrid for highly efficient photodegradation of methylene blue dye under visible light illumination

Most dyes are carcinogenic; thus, they must be removed from the water to save aquatic and human life. Among the various methods, the photocatalytic degradation of dyes is attracting much attention due to the easy strategy driven by the solar light. Herein, we report the fabrication of nickel ferrite (NiFO), lanthanum ferrite (LFO) and their composite are utilized as a light-driven catalyst for the deprivation of significant commercial dyes. The straightforward microemulsion method is used to produce both pure ferrite materials and their composite counterparts. The phases of the synthesized materials were verified through XRD analysis while scanning electron microscopy was employed to examine their morphology. The average crystallite size of the LFO, NiFO and their composite was 53, 62 and 42 nm, respectively. The elemental composition of the pristine and composite was confirmed by the energy dispersive spectroscopic analysis, indicating no other impurity in the materials. The optical properties are analyzed via UV visible and photoluminescence to measure the band gap value of 2.05, 1.73 and 1.9 eV for LFO, NiFO and their composite, respectively. It is observed that the LaFeO3/NiFe2O4 has the highest photodegradation efficiency (92 %) as compared to the LFO (LaFeO3) and NiFO (NiFe2O4). The composite material also showed excellent reusability as well as good stability. It was also confirmed that OH radicals are the major contributor toward the dye degradation, as confirmed by the scavenger tests. The higher mineralization of methylene blue in the occurrence of composite as a catalyst may cause rapid charge transfers, as confirmed by EIS, and it may stop the recombination of electrons/hole pairs due to suitable band alignments.

NiFe2O4 nanoparticles for non-volatile bipolar resistive switching memory device

The present work reports the chemical synthesis of NiFe2O4 (NFO) nanoparticles (NPs) and its use as a switching layer material in resistive switching (RS) devices. Various analytical techniques were used to confirm the phase, composition, and optical properties of the NFO NPs. With the support of the x-ray diffraction technique, crystal structure (cubic spinel) and crystallite size (20.12 nm) were determined. Field emission scanning electron microscopy confirmed the material morphology. Raman Spectroscopy and Fourier Transform Infrared Spectroscopy were applied to identify the NFO NPs functional groups. The Ag/NFO/fluorine-doped tin oxide device was fabricated, which shows bipolar RS with good endurance (104cycles) and retention (6 × 103 s) properties. Moreover, the device’s conduction and RS mechanisms were also carried out.

Low temperature in situ fabrication of NiFe2O4/tetragonal-BiVO4/Bi2MoO6 ternary heterostructure: A conjugated step-scheme multijunction photocatalyst with synergistic charge migration for antibiotic photodegradation and H2 generation

Rational design of novel conjugated step-scheme (S-scheme) multijunction heterostructure with synergistic charge channelization, superior light harvesting efficiency and strong redox ability is a pioneering approach to mimic natural photosynthesis process. Herein, a mild cetyltrimethyl ammoniumbromide (CTAB) assisted one pot reflux synthesis route is designed for in situ integration of metal organic framework (MOF)-derived NiFe2O4 with tetragonal-BiVO4 (t-BiVO4) and γ-Bi2MoO6 to prepare NiFe2O4/t-BiVO4/Bi2MoO6 (NFO/BVO/BMO) ternary composites. Morphologically, fine dispersion of NiFe2O4 (NFO) quantum dots over γ-Bi2MoO6 (BMO) and t-BiVO4 (BVO) nanoplates yielded three types of microscopic heterojunctions among BMO-BVO, BVO-NFO and BMO-NFO phases. The ternary composites displayed important physicochemical attributes including high surface area, strong optical absorption, superior charge mobility and higher excited state lifetime which accounted for its improved photocatalytic activity towards ciprofloxacin degradation (>99% in 90 min) and H2 evolution (1.11 mmolh-1g−1, photon conversion efficiency 18.5%). Kinetics study revealed 12–55 fold higher ciprofloxacin photodegradation activity and 31–41 times higher H2 evolution rate for the ternary composite in comparison to the pure semiconductors. A conjugated S-scheme charge transfer mechanism has been deduced from comprehensive band position analysis and radical trapping study to explain the enhanced photocatalytic activity. This work for the first time demonstrated the rational construction of conjugated S-scheme heterostructures with potential application in water remediation and green H2 production.

Surface-Reconstructed Ru-Doped Nickel/Iron Oxyhydroxide Arrays for Efficient Oxygen Evolution.

The generation of an active phase through dynamic surface reconstruction is a promising strategy for improving the activity of electrocatalysts. However, studies investigating the reconstruction process and its impact on the intrinsic properties of the catalysts are scarce. Herein, the surface reconstruction of NiFe2 O4 interfaced with NiMoO4 (Ru-NFO/NMO) facilitated by Ru doping is reported. The electrochemical and material characterizations demonstrate that Ru doping can regulate the electronic structure of NFO/NMO and induce the high-valence state of Ni3.6+ δ , facilitating the surface reconstruction to highly active Ru-doped NiFeOOH/NiOOH (SR-Ru-NFO/NMO). The optimized SR-Ru-NFO/NMO exhibits promising performance in the oxygen evolution reaction, displaying a low overpotential of 229mV at 10mA cm-2 and good stability at varying current densities for 80h. Density functional theory calculations indicate that Ru doping can increase the electron density and optimize intermediate adsorption by shifting the d-band center downward. This work provides valuable insights into the tuning of electrocatalysts by surface reconstruction and offers a rational design strategy for the development of highly active oxygen evolution reaction electrocatalysts.

Nd-doped NiFe2O4 and its composite with CNTs to tune photocatalytic activity

Rare earth-doped spinel nano ferrites are attaining importance as heterogeneous nanocatalysts for the degradation of organic effluents. Rare earth metal doping increases the electrical and optical properties, as well as the surface-to-volume ratio of the bare sample. In this work, NiFe2O4 (NF) and Nd-NiFe2O4 (NF-1) were successfully synthesized via the co-precipitation route. Carbon nanotubes (CNT)-based nanocomposite (NF-2) was prepared using the ultra-sonication method. The prepared materials were analyzed via various physiochemical approaches. The degradation efficiency of these materials was analyzed for the degradation of Rhodamine B, methylene blue, and benzoic acid. NF-2 shows the highest efficiency among all the prepared catalysts. NF-2 shows 83.87%, 90.80%, and 66.96% degradation of Rhodamine B, methylene blue, and benzoic acid, respectively. The reason for the superior activity of NF-2 is the existence of rare earth Nd ions and CNTs. The surface area of NF increases due to the presence of carbon nanotubes and enhanced surface area provides more active sites for the degradation reaction.

Use of Some Metalferrites as Catalyst in Benzil-Benzilicacid Rearrangement Reaction

Magnesium ferrite was used to catalyse the Benzil-Benzilic acid rearrangement reaction of 1,2-rearrangement of 1,2-diketones to α-hydroxy carboxylic acids in presence of a base. Magnesium ferrite was prepared by hydrothermal process. It was characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction Spectroscopy (XRD), and Energy Dispersive X-Ray Spectroscopy (EDX). The crystalline size of magnesium ferrite was found to have 82.47nm and these are irregular in shape. It was found that the yield of the product (benzilic acid) in the presence of Mg ferrite was 81.6%, which is almost 2.3 times the yield obtained in the absence of catalyst. A comparative study was made with different metal ferrites as catalyst and it was found that the activity of metal ferrites followed the order: MgFe2O4 &gt; Cu Fe2O4 &gt; Ni Fe2O4 &gt; Co Fe2O4 &gt; Zn Fe2O4

Effects of chemical composition on lightweight aggregates produced from contaminated soil: Phase regulation, immobilization mechanism and leaching prediction

Contaminated soil induces serious environmental risk due to the presence of hazardous components. The preparation of lightweight aggregate (LWA) is a widely accepted technique to treat contaminated soil. This study investigated the effect of contaminated soil composition on the physical properties and immobilization of heavy metals (Cu, Cr, Pb and Ni) of LWA. Phase regulation, immobilization mechanism and leaching prediction of LWA were analyzed. Results showed that SiO2 and Al2O3 were detrimental to the bloating performance of LWA, whereas fluxing components (Fe2O3, Na2O, K2O, CaO, and MgO) are all conducive. Fluxing components can bring more liquid phase, resulting in a lower density of LWA. The addition of Fe2O3 facilitated the immobilizing Cu and Cr owing to the formation of spinel phases, such as (Mg,Cu)(Fe,Ni)2O4 and Fe(Cr,Al)2O4. Glassy phase could encapsulate heavy metals remarkably, while the high content of fluxing components was unfavorable to the immobilization of Cu and Ni. As network modifiers, Cu and Ni could participate in the formation process of glassy phase, and get encapsulated by liquid phase from fluxing components. Based on the leaching results of Cu, Cr, Pb, and Ni, leaching prediction of LWA was conducted by characteristic indexes and Riley's phase diagram. This research could guide the manufacturing process and leaching control of LWA recovered from contaminated soil.

Study on Enhanced Magnetostriction in (x)PbZr0.52Ti0.48O3-(1-x)NiFe2O4 Composites by Magnetoelectric Effect

Magnetoelectric composites (x)PbZr0.52Ti0.48O3(PZT)-(1-x)NiFe2O4 (NFO) with x values of 0.15, 0.30, 0.45, 0.55, 0.75, and 0.85 mol% were obtained by traditional solid phase reaction. The measured magnetic and magnetostriction properties are strongly dependent upon the molar fraction (1-x) of the NFO in the composites. The maximum magnetostriction coefficient of -52.4 ppm was observed in 0.3PZT-0.7NFO composite ceramic. All the magnetostriction in the composites is larger than the reported values. The larger magnetostriction would result from the magnetoelectric (ME) effect of the composites. We propose a model of the magnetostriction within the composites consisting of strain and polarization. The relationship between the ME effect and magnetostriction is discussed in the qualitative features of this model. This magnetoelectric composite material maintains a strong magnetostrictive effect, which can be used in multifunctional sensors. It will provide new ideas for the design of multifunctional sensors in the future.

Pb(II) ions removal via green spinel NiFe2O4 loaded on g-C3N4 nanomaterials

A novel nickel ferrite-graphitic carbon nitride (NFCN) composite was prepared from green NiFe 2O4 nanomaterials and g-C3N4 using ultrasonic power in alcoholic medium for adsorbing Pb(II) ions from aqueous solutions. The X-ray diffraction (XRD) results showed the mutual existence of both the ferrite and nitride phases, which were confirmed by scanning electron microscope (SEM) morphological images, EDX analysis, X-ray photoelectron spectroscopy (XPS) chemical composition and Fourier transform infrared spectroscopy (FTIR) band identification. The Brunner-Emmet-Teller (BET) analysis revealed a highly porous nanostructure with surface area of 118 m2g−1 that made it a competent adsorbent to achieve a maximum adsorption capacity of 540.55 mg g−1 for Pb(II) ions from aqueous solution under the optimal conditions. Furthermore, the adsorption kinetics and adsorption isotherm analysis showed that the adsorption process followed the pseudo-second-order kinetic model and Langmuir adsorption model, specifying that the adsorption of Pb(II) ions by the NiFe2O4@g-C3N4 nanocomposite is monolayer chemisorption. The adsorption mechanism was found to be intraparticle as well as film diffusion controlled. On the other hand, the -NH2 and -OH functional groups within the nano-adsorbent structure were proved to coordinate with the Pb(II) ions, as supported by the FTIR analysis. The results demonstrate that the NiFe2O4@g-C3N4 nanocomposite has a high capacity and is reusable for Pb ion adsorption.

Magnetic coordination polymer for dye removal and antibacterial activity

BackgroundColor elimination from dye wastewater is one of the major environmental concerns, therefore, finding an eco-friendly, recyclable, and effective sorbent for dye treatment is very important. This work aims to scrutinize the performance of a new magnetic amino-coordinated metal–organic framework, namely NiFe2O4/[Zn4(BTC)2(Hbtc)(L-His)2(H2O)4] 1.5H2O (NF/LHTZn), in Acid Red 14 (AR14) and methylene blue (MB) elimination, and antibacterial activity. MethodHere, NiFe2O4 (NF), LHTZn, and NF/LHTZn materials were successfully constructed via the hydrothermal condition and checked via several characterizations (i.e., X-ray diffraction and Fourier transform infrared). Batch adsorption studies were performed to appraise the influence of operational factors like solution preliminary concentration (A), adsorbent dosage (B), contact time (C), temperature (D), and pH on the removal of MB and AR14 dyes. The response surface methodology (RSM) has helped to optimize two dye sorption processes. Significant findingsBased on experimental results, sorption kinetics were correctly matched by the pseudo 2nd order model for both dyes. Freundlich's isotherm indicated that the best fit for MB removal and maximal uptake capacity (Qmax) was 375.93 mg/g, while Langmuir was best fitted for AR14 (Qmax= 276.24). Thermodynamic results revealed that both dye adsorption was spontaneous in nature. According to RSM data, the maximum removal of MB was 292.61 mg/g under optimal conditions, A= 100 mg/L, B= 0.3 g/L, C= 140 min, D= 30 °C and, pH 7, and a maximum AR14 adsorption of 272.35 mg/g gained at an A= 100 mg/L, B= 0.3 g/L, C= 126 min, D= 40 °C and pH 2. Based on disk diffusion results, NF/LHTZn has also a proper antibacterial performance toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.

Construction and characterization of nano-oval BaTi0.7Fe0.3O3@NiFe2O4 nanocomposites as an effective platform for the determination of H2O2

Talented di-phase ferrite/ferroelectric BaTi0.7Fe0.3O3@NiFe2O4 (BFT@NFO) in oval nano-morphology was chemically synthesized using controlled sol–gel processes and calcined at 600 °C. The effects of shielding using NiFe2O4 (NFO) nanoparticles on the microstructure, phase transition, thermal, and relative permittivity of BaTi0.7Fe0.3O3 (BTF) nano-perovskite were systematically explored. X-ray diffraction patterns and Full-Prof software exhibited the forming of the BaTi2Fe4O11 hexagonal phase. TEM and SEM images demonstrated that the coating of BaTi0.7Fe0.3O3 has been successfully controlled with exquisite nano-oval NiFe2O4 shapes. The NFO shielding can significantly promote the thermal stability and the relative permittivity of BFT@NFO pero-magnetic nanocomposites and lowers the Curie temperature. Thermogravimetric and optical analysis were used to test the thermal stability and estimate the effective optical parameters. Magnetic studies showed a decrease in saturation magnetization of NiFe2O4 NPs compared to their bulk system, which is attributed to surface spin disorder. Herein, characterization and the sensitive electrochemical sensor were constructed for the evaluation of peroxide oxidation detection using the chemically adjusted nano-ovals barium titanate-iron@nickel ferrite nanocomposites. Finally, The BFT@NFO exhibited excellent electrochemical properties which can be ascribed to this compound possessing two electrochemical active components and/or the nano-ovals structure of the particles which can further improve the electrochemistry through the possible oxidation states and the synergistic effect. The result advocates that when the BTF is shielded with NFO nanoparticles the thermal, dielectric, and electrochemical properties of nano-oval BaTi0.7Fe0.3O3@NiFe2O4 nanocomposites can be synchronously developed. Thus, the production of ultrasensitive electrochemical nano-systems for the determination of hydrogen peroxide is of extensive significance.

Electrodeposited NiFe2O4/Cu2O heterostructure thin films with enhanced photocurrent generation

In comparison with single-phase materials, heterostructures have been known for superior water splitting applications. In this study, Cu2O and NiFe2O4 are chosen to fabricate thin film heterostructures. Cu2O is electrodeposited at 60 °C for 5 min on ITO-coated glass substrates using three-electrode system. After deposition, the phase formation is confirmed using powder x-ray diffraction studies. The NiFe2O4 (NFO) thin films are deposited using RF sputtering method at room temperature for 2 h on Cu2O/ITO substrates to obtain NFO/Cu2O/ITO Type-II heterostructure. The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) cross-sectional images show that the thickness of NFO layer is 120 nm and Cu2O layer is 1.5 µm. The photocurrent density of Cu2O on ITO is 0.08 ± 0.002 mA/cm2, and it increased to 0.12 ± 0.002 mA/cm2 after adding NFO layer on Cu2O film due to Type-II heterojunction formation.

Correlation between the thickness of NiFe2O4 and hydrogen production performance for solid oxide electrolysis cells

This study investigates the influence of cathode thickness on the performance of solid oxide electrolysis cells with 20% H2O–80% N2 at 800 °C. NiFe2O4 (NFO) was used as the cathode material. The thickness of the cathode was controlled to be approximately 10–70 μm. NFO can be considered as a mixed electron and oxide-ion conductor because the cell performance changes with its thickness. Furthermore, the ohmic and polarization resistances decreased significantly when the cathodic thickness increased to 30 μm. The performance improvement was because of the increase in conduction networks. In addition, the electrochemical reaction area increases to lower polarization resistances. However, with a cathodic thickness of 30–70 μm, the ohmic resistance increased significantly because the conduction paths became longer from the current collector to the reaction area. In addition, the polarization resistance increased slightly owing to the difficulty in gas diffusion.

Role of Al3+ and Cr3+ Ions on Structural, Optical, Magnetic, and Impedance Properties of AlyCrxZn(0.4-y)Ni(0.6-x)Fe2O4 Nanoparticles

Role of Al3+ and Cr3+ Ions on Structural, Optical, Magnetic, and Impedance Properties of AlyCrxZn(0.4-y)Ni(0.6-x)Fe2O4 Nanoparticles

Effect of calcination temperature on sensing performance of YSZ based electrochemical H2S gas sensor with a NiFe2O4 electrode

Electrochemical gas sensors based on yttria-stabilized zirconia (YSZ) film have attracted ascending attention for detecting H2S. Due to the poor sinterability of YSZ film, high-temperature calcination is usually required in the preparation procedure to ensure the good contact between YSZ and sensing electrode, which could particularly limit the triple phase boundary (TPB) length at the interface of H2S|YSZ|sensing electrode as well as the porosity of sensing electrode. Therefore, the calcination temperature would significantly affect the sensing performance, which has been ignored in reported studies. In this work, YSZ based electrochemical gas sensors with NiFe2O4 (NFO) sensing electrode are prepared to detect H2S at ppb-level. The effect of the calcination temperature of NFO sensing electrode on the sensing performance is investigated. The sensor with an optimal calcination temperature of 1000 °C delivers a response value of − 42 mV for 500 ppb H2S at 460 °C with a detection limitation of 10 ppb H2S. Good linear slopes with a sensitivity of − 13.1 mV/decade toward 20–100 ppb H2S and a sensitivity of − 46.9 mV/decade toward 100–500 ppb H2S are obtained. Meanwhile, the sensor also displays attracting stability and short response/recovery time. The good sensing performance is attributed to enhanced TPB length, good porosity of NFO electrode and limited interaction between the NFO and YSZ film by optimizing the calcination temperature of NFO sensing electrode.

Role of Al3+ and Ti4+ ions on structural, optical and electrical properties of AlyTixZn(0.4−y) Ni(0.6−x)Fe2O4 nanoparticles

Role of Al3+ and Ti4+ ions on structural, optical and electrical properties of AlyTixZn(0.4−y) Ni(0.6−x)Fe2O4 nanoparticles