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SEM images of thin layer of polyaniline with 5 cycles of electrodeposition with a 2 μm and b 200 nm scale bar
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The purpose of this study is preparation of polyaniline–lead ferrite, polyaniline–cobalt ferrite and polyaniline/nickel ferrite thin layers. The electromagnetic pollution is a serious problem in the world that can be solved by electromagnetic interference (EMI) shielding. The EMI layers can be synthesized by conductive layer composed by magnetic pa...
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In this study, soft magnetic metal was coated on carbon fibers (CFs) using an electroless FeCoNi-plating method to enhance the electromagnetic interference (EMI) shielding properties of CFs. Scanning electron microscopy, X-ray diffraction, and a vibrating sample magnetometer were employed to determine the morphologies, structural properties, and ma...
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... The quantified EDX images has confirmed the presence of Co, Cu, Y, Fe, O elements exhibiting no external impurities introduced in the sample. The Y-Cu co-doped CFO have been found stable and can easily sustain in the environment with all its physical and chemical properties conserved [32]. Table 6 has confirmed the atomic % of all the elements present in the Cu/Y co-substituted cobalt ferrites. ...
This paper explores yttrium and copper co-doped cobalt ferrite [Co1−x Cu x Fe1.85Y0.15O4] synthesized via the sol–gel auto-combustion route (0.0 ⩽ x ⩽ 0.08). Investigating the impact of co-dopants on CoFe2O4, the study reveals altered cation distribution affecting the structure, multiferroic, and electrical properties. X-ray diffraction studies show nanocrystalline co-doped cobalt ferrites with lattice expansion and smaller grains due to Cu–Y co-doping. Fourier transform infrared spectroscopy confirms inverse spinel family classification with tetrahedral lattice shrinkage. Field emission scanning electron microscopy indicates a grain size of approximately 0.12 μm. Ferroelectric analysis reveals a peak saturation polarization of 23.42 μC cm⁻² for 8% copper doping, attributed to increased Fe³⁺ ions at tetrahedral sites. Saturation magnetization peaks at 54.4706 emu g⁻¹ for 2% Cu²⁺ ion substitution [Co0.98Cu0.02Fe1.85Y0.15O4] and decreases to 37.09 emu g⁻¹ for 4% Cu substitution due to irregular iron atom distribution at tetrahedral sites. Dielectric studies uncover Maxwell–Wagner polarization and high resistance in grain and grain boundaries using impedance spectroscopy. Fabricated hydroelectric cells exhibit improved ionic diffusion, suggesting their use in potential hydroelectric cell applications.
... Also, the crystallite size of the crystal and the strain in the crystal lattice were calculated via Williamson-Hall relation written as Eq. 3 [44]. ...
Today, electromagnetic pollution is one of the most important factors that can endanger human health and have a destructive effect on electrical devices. The use of conductive composite layers including magnetic nanoparticles can play an important role in absorbing electromagnetic waves and eliminate electromagnetic pollution. In this research Ba0.5Sr0.5Fe12O19 and Ni0.5Mn0.5Fe2O4 nanoparticles were synthesized via the microwave radiation method and using lemon juice as a surfactant. Then different percentages of Ba0.5Sr0.5Fe12O19 and Ni0.5Mn0.5Fe2O4 nanoparticles are electrodeposited as a nanocomposite in the form of a thin layer. The structure, crystalline size, and strain of nanoparticles were investigated via X-ray diffraction. The morphology and shape of nanoparticles were studied by field emission scanning electron microscope. The kinetic roughening of nanocomposite thin films was studied using atomic force microscope. Magnetic hysteresis loop of nanoparticles and nanocomposite thin films curved via vibration sample magnetometer. The reflection loss of the samples were measured via vector network analyses. The purpose of this research is to find the appropriate percentage of the composition of Ba0.5Sr0.5Fe12O19 and Ni0.5Mn0.5Fe2O4 nanoparticles that has the largest range of absorption of electromagnetic waves.
... Ferrite nanoparticles with the general formula M-Fe 2 O 4 have been considered attractive with their unique construction and unparalleled magnetic character. The magnetic ferrite catalysts can be prepared by using different techniques such as sol-gel, coprecipitation, and hydrothermal techniques [9][10][11][12][13]. Among them, the coprecipitation technique is a favorable method due to it being cost-effective, simple, environmentally friendly, and amenable to operation at relatively low temperatures. ...
The major challenge of hydrogen production via photocatalytic water-splitting is to utilize active photocatalysts that respond to a wide range of visible light. In this work, hybrid nanostructures purposed to combine the tunable magnetic behavior of soft/semi-hard magnetic particles have shown advantageous photoactivity. A series of photocatalysts based on ferrite nanoparticles, magnetite nanoparticles (MNPs), cobalt ferrite nanoparticles (CFNPs), magnetite nanoparticles coated on cobalt ferrite nanoparticles (MNPs @ CFNPs), and cobalt ferrite nanoparticles coated on magnetite nanoparticles (CFNPs @ MNPs) were prepared. The size, morphology, magnetic properties, and optical activity of the prepared nanoparticles were characterized using multiple techniques. CFNPs @ MNPs had the largest particle size (~14 nm), while CFNPs had the smallest (~8 nm). The saturation magnetization of CFNPs @ MNPs was the highest at 55.45 emu g−1. The hydrogen yield was 60, 26, 3.8, and 93 mmole min−1 g−1 for MNPs, CFNPs, MNPs @ CFNPs, and CFNPs @ MNPs. CFNPs @ MNPs displayed a superior photocatalytic performance for hydrogen production under the magnetic force as appropriate materials for water-splitting processing.
... Where, λ is the wavelength of the X-ray source (0.154 nm), is the full width at half maximum intensity (FWHM) and θ is the angle of reflection measured in radians [34]. The (111) peak, the most intense for Ni in the composite, was used for the calculation of the crystallite size. ...
In this work, Ni NPs have been in-situ synthesized using hydrazine as a reducing agent and immobilized on nanofibrillated cellulose (Ni/NFC) and magnetic nanofibrillated cellulose (Ni/Fe 3 O 4 @NFC) as green supports. The structure and morphology of the Ni/Fe 3 O 4 @NFC nanocomposite clarified high purity single-phase spherical-shaped Ni nanoparticles of about 30 nm distributed on the surface of nanocellulose as compared to the larger size of star shape particle in Ni/NFC. The catalytic activity of both nanocomposites was investigated for the reduction of 4-nitrophenol (4-NP), Methyl Orange (MO), and Methylene Blue (MB). The results demonstrated high catalytic efficiency toward the removal of water pollutants in a short reaction time. The reduction rate constants (k) of freeze-dried Ni/Fe 3 O 4 @NFC catalyst were 30 ×10-3 s-1 , 17.3×10-3 s-1 , and 6.9 ×10-3 s-1 , for 4-NP, MO, and MB respectively, which were higher than those of synthesized Ni/NFC and other reported Ni-based catalysts. Moreover, the catalyst could be easily magnetically recoverable and reusable in other cycles.
... Darwish MA et al. studied the epoxy/ferrite composite for electrical and dielectric properties and found that composites of epoxy/ferrite had higher AC conductivity than that of epoxy resin and also found that a higher amount of ferrite in the composites cause defects and decreased the AC conductivity [25]. Leila Abbasi et al. studied polyaniline/ferrites thin films (lead, nickel and copper ferrite) for the magnetic properties and their applications in electromagnetic shielding materials [26]. Elsayed AH et al. studied the magnetic properties of polyaniline/ferrites and found the composites to be ferromagnetic and also found that the samples showed increased thermal stability with the addition of ferrites to polyaniline [27]. ...
Nickel ferrite nanoparticles are prepared by using a low-temperature self-propagating solution combustion method using urea as fuel. The prepared nickel ferrite nanoparticles were doped with polyaniline in the three different weight ratios of 10%, 30% and 50% by using an in situ polymerization method and by adding ammonium persulfate as an oxidizing agent. The obtained samples were characterized by using XRD, FTIR, SEM and a UV-visible spectrophotometer. XRD examined crystalline peaks of ferrites and amorphous peak of polyaniline and confirmed the formation of the composites. FTIR examined the chemical nature of samples and showed peaks due to polyaniline and the characteristic peaks that were less than 1000 cm −1 wavenumber were due to metal-oxygen bond vibrations of ferrites. AC conductivity increased with frequency in all samples and the highest AC conductivity was seen in polyaniline/nickel ferrite 50%. DC conductivity increased in all samples with the temperature showing the semiconducting nature of the samples. Activation energy was evaluated by using Arrhenius plots and there was a decrease in activation energy with the addition of ferrite content. The UV-visible absorption peaks of polyaniline showed shifting in the composites. The optical direct and indirect band gaps were evaluated by plotting Tauc plots and the values of the optical band gap decreased with addition of ferrite in polyaniline and the Urbach energy increased in the samples with 10%, 30% and 50% polyaniline/nickel ferrite composites. The optical properties of these composites with a low band gap can find applications in devices such as solar cells.
... The average particle crystalline size is calculated by the Scherrer equation, (Eq. 1), that β is the width of the observed diffraction peak at its half maximum intensity, λ is the x-ray wavelength, 0.154 nm and θ is the diffraction position [18]. The average crystalline size for NiFe2O4 particles synthesis for 2 and 12 h heating time were found to be about 29 and 58 nm respectively. ...
... Then, the strain (ɛ) of the lattice crystal was evaluated using Eq. (3) of (111) planes of Ag2O crystals [47,48]. The value of this strain can be obtained from the resulting peak broadening. ...
Silver oxide (Ag2O) nanoparticles have been successfully synthesized through several methods, namely sol-gel, sonochemical, and biological methods. X-ray diffraction studies revealed that the sonochemical method produces silver oxide with high phase purity, then the sol-gel method produces another phase, namely silver crystals, while the biological method produces Ag3PO4 phase from the precursor media. The research showed that the sol-gel method had the smallest crystallite and particle sizes of 9.5 and 232.7 nm, respectively, compared to sonochemical and biological methods. It is known that the specific surface area of the sol-gel method has the largest value, namely 60.09 m 2 /g, compared to the sonochemical and biosynthetic methods, which are 51.78 and 24.77 m 2 /g, respectively. Scanning electron microscopy study showed homogeneous spherical nanoparticles of silver oxide in the sol-gel and sonochemical methods, however, the biological method resulted in the formation of non-spherical silver oxide nanoparticles in the form like flakes.
... The XRD pattern of annealed ZnCF nanoparticles with seven distinctive diffraction peaks was observed at 2θ angles of 30. 511) and (440), respectively, as shown in Figure 2 [66][67][68]. Quantitatively, the average crystallite size (nm) of the nanoparticles was calculated using full width at half maximum (FWHM) of the (311), most intense peak of above crystal using Debye Scherre's formula as mentioned in below [46,69,70]: ...
There has been immense development in the production and use of recyclable materials for dye degradation which are advancing in a wide perspective to minimise the environmental impacts. Therefore, an efficient, eco-friendly, magnetically separable and recyclable catalyst is being reported that has the potential to remove dyes [Tropeolin000, Congo red and Orange G] from wastewater. The catalyst has a backbone containing Zinc, Cobalt and Iron in the ratio Zn0.5Co0.5Fe2O4 with a coating of polyaniline that enhances its dye degradation capability. These synthesised PANi-coated ferrites have been characterised by FTIR, XRD, SEM and EDX techniques, and the photocatalytic activity has been explored using UV–Vis spectrophotometer at ambient conditions. A dye removal efficiency of as high as more than 99.9% has been reported for dye Orange G and above 90% for Tropeolin000. The mechanistic pathway that can be involved in the dye degradation has also been discussed.
... where β is the width of peaks in half maximum intensity, λ is 1.54 Å, θ is the angle of diffraction, and t is the size of crystallite (Abbasi et al., 2021). The crystallite size of SrFe 12 O 19 nanoparticles was calculated to be 34 nm and BaFe 12 O 19 nanoparticles was calculated to be 28 nm. ...
... where ε is lattice strain and β, θ, and λ are the same as in Eq. 1 (Abbasi et al., 2021 Roughness is checked on the surface of many materials and thin layers. The roughness or kinetic roughening for layers depended to time of deposition or thickness of films. ...
In this work, new polymeric aniline-barium ferrite and aniline-strontium ferrite thin layers were synthesized. In the first step, hexaferrites nano-additives were prepared by applying ultra-sound and microwave irradiation. Then, hexaferrites were added to aniline electrolyte solution separately. The electrodeposition of aniline as a polymeric matrix and hexaferrite as nano-additives was performed in an electrochemical cell in the presence of various acids. Scanning electron microscopy images were applied for morphology investigation and measuring average particle size. Energy dispersive X-ray spectroscopy was applied for elemental detection and analysis, as well as presence confirmation of nanoparticles. Atomic force microscopy was applied for surface roughness analysis of thin films. Magnetic property of the nanoparticles and polymeric nanocomposites was checked and measured by vibrating sample magnetometer. The crystallinity, crystallite size, and phase of samples were confirmed by X-ray diffraction pattern analysis.
... Metal ferrites nanoparticles with the general formula MFe 2 O 4 (M ¼ divalent metal ion such as Ni, Mg, Mn, Cu, Co, Fe, etc.) have gained considerable attention due to their unique structural, excellent magnetic, chemical stability, and low cost [14,15]. The metal ferrites that are to be used as electrocatalysts can be synthesized by various chemical and physical methods such as spray pyrolysis [16], hydrothermal [17], sol-gel [18], magnetron sputtering [19] and electrodeposition method [20,21]. Among them, coprecipitation method is considered as inexpensive and simple technique, reproducible and accessible route for mass production of magnetic spinel ferrite nanoparticles, in which the control of size and size distribution is obtained by controlling the relative rates of nucleation and growth during the synthesis process [22,23]. ...
Developing low-cost, stable, and robust electrocatalysts for hydrogen evolution reaction (HER) is highly desirable for large-scale application. In this study, a highly efficient electrocatalysts of metal ferrites (MFe2O4, M = Co, Ni, Zn, Cu) with superior activity and durability are successfully fabricated on copper substrate through a facile co-precipitation method followed by doctor-blading deposition. The electrocatalytic performance of CoFe2O4, NiFe2O4, ZnFe2O4 and CuFe2O4 electrodes for hydrogen evolution reaction is studied in alkaline media using polarization curves and electrochemical impedance spectroscopy (EIS). Among them, CoFe2O4 presented the best electrocatalytic activities for HER with extremely low overpotentials of 270 mV (vs. RHE) at a current density of 10 mA cm⁻² in 1 M KOH. The electrocatalytic activity of MFe2O4 (M = Co, Ni, Zn, Cu) for HER to generate current density of 10 mA cm⁻² with low overpotential followed the order of CoFe2O4 > CuFe2O4 > NiFe2O4 > ZnFe2O4. The highly improved HER performance of CoFe2O4 is mainly due to a large number of exposed active sites, high electrical conductivity and low apparent activation energy, which are confirmed by a remarkable electrochemically active surface area (ECSA = 53.17 cm²), Nyquist plots analysis and Arrhenius plots measurement, respectively. Moreover, the CoFe2O4 electrode showed outstanding electrocatalytic stability even after 1000 cyclic voltametry tests. These results provide a promising avenue for developing cost-effective and high-efficiency electrocatalysts based on earth-abundant transition metal ferrite as advanced electrodes for large-scale energy conversion processes.
