Optical and magnetic properties of Mg-doped ZnFe2O4 nanoparticles prepared by rapid microwave combustion method
TL;DR: In this paper, powder X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive Xray analysis, UV-Visible diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM).
About: This article is published in Superlattices and Microstructures.The article was published on 2013-12-01 and is currently open access. It has received 227 citations till now. The article focuses on the topics: Band gap & Crystallite.
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TL;DR: In this paper, the performance of different noble and transition metals (Ni, Mn, Fe and Ag) doped ZnO (M/ZnO) nanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and UV-vis spectrophotometry.
Abstract: The ZnO and different noble and transition metals (Ni, Mn, Fe and Ag) doped ZnO (M/ZnO) nanostructures were synthesized by hydrothermal method. The ZnO and M/ZnO photocatalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and UV–vis spectrophotometry. The obtained XRD and FESEM results confirmed the well dispersion of Ni and Ag nanoparticles and highly agglomerated Mn and Fe nanoparticles on the surface of ZnO nanostructures. The optical band gap value was calculated as 3.24, 3.15, 3.10, 3.05 and 3.00 eV from UV–vis diffuse reflectance spectra of ZnO, Ag/ZnO, Ni/ZnO, Fe/ZnO and Mn/ZnO photocatalysts, respectively. The results of the photocatalytic degradation of tartrazine in aqueous solutions under the UV-light showed that Ni/ZnO exhibited higher photocatalytic activity than the other ones. Mn/ZnO demonstrated the lowest photocatalytic activity among the synthesized photocatalysts. Thus, Ni and Ag exhibited synergistic effect while Fe and Mn exhibited antagonistic effect on the ZnO photocatalytic activity. The maximum degradation rate of tartrazine was obtained to be 98.2% in the 60 min using Ni/ZnO. The plausible mechanisms were proposed and discussed for the enhanced or decreased photocatalytic activities resulting from different metals doped ZnO.
217 citations
TL;DR: In this paper, high-stable and magnetically recoverable spinel ferrite nanoparticles were proposed as heterogeneous catalysts for the reduction of nitroarenes, and the morphological characteristics, structural exploration, surface, optical, vibrational and magnetic properties were performed using powder X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X -ray, N 2 sorptiometry, diffused UV-vis reflectance spectroscopy, FTIR, vibrating sample magnetometer (VSM) and thermokinetic analysis via TGA
Abstract: Highly stable and magnetically recoverable MFe 2 O 4 (M = Zn, Co, Mn) spinel ferrite nanoparticles; synthesized using sol gel-hydrothermal technology via utilizing polyvinyl alcohol surfactant, were proposed as heterogeneous catalysts for the reduction of nitroarenes. The morphological characteristics, structural exploration, surface, optical, vibrational and magnetic properties were performed using powder X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray, N 2 sorptiometry, diffused UV–vis reflectance spectroscopy, FTIR, point of zero charge, vibrating sample magnetometer (VSM) and thermokinetic analysis via TGA technique. The results showed that MnFe 2 O 4 exhibited the best performance in the reduction of 4-nitrophenol (4-NP), 2,4,6 tri-nitrophenol (2,4,6-NP) and 4-nitroaniline (4-NA) and revealed 100% conversion into the corresponding amino derivatives in 270 sec with rate constant equal 0.01061 s −1 , 0.01134 s −1 and 0.01355 s −1 , respectively. The superiority of the catalytic reduction of MnFe 2 O 4 was due to increasing the pore radius and pore volume (6.75 nm, 0.227 cm 3 /g) values compared to other nanoferrites. The synthesized nanoferrites indicate independence of the activity on crystallite sizes due to the insignificant margin of change (from 6 to10 nm). Conversely, decreasing the activity of ZnFe 2 O 4 was due to increasing the Zn 2+ ions size that induces an increase in lattice parameter values and thus increases the long-range electron transfer between Fe 2+ –Fe 3+ ions. The MnFe 2 O 4 catalyst that presented the highest saturation magnetization (135 emu/g) indicated the highest reduction potential for 4-NA comparatively in the presence of NaBH 4 and the reduction reaction followed pseudo first-order kinetics. Increasing the reduction performance of 4-NA compared to other nitroaromatics on MnFe 2 O 4 was explained based on the formed intermediates, their reactivities, hydrophobicity and to point of zero charges. It has been explored that the reduction efficacy of 4-NP was enhanced on MnFe 2 O 4 with the addition of ammonium oxalate and benzoquinone where it was inferior following the addition of tertiary-butyl alcohol. More important correlations concerning the effect of octahedral sites, residual organics, heat of activation ( E a ) and activation free energy (Δ G *) values; determined while the removal of citrate/PVA moieties, on nitroarenes reduction rates were well scrutinized and discussed.
212 citations
TL;DR: The present review focuses on different techniques for synthesis of MnZn ferrites in literature, their characterization tools, effect of doping on the properties of Mn Zn ferrite and finally about their applications.
184 citations
TL;DR: In this article, the temperature dependent spinel phase formation and percentage weight loss was studied by thermogravimetric and differential thermal analysis (TG-DTA), which showed the formation of cubic spinel structure with single phase in the Zn-Mg ferrites.
176 citations
TL;DR: In this paper, the optical band gap of the prepared samples has been calculated using Tauc plots and have been found to increase with increase in Ni2+content from 4.50 eV (x = 0.50 ) to 5.60 eV(x= 0.60 ) for all samples.
150 citations
References
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13 Dec 1990
TL;DR: Ferrite Transformers and Inductors at High Power Ferrite Transformers for Magnetic Recording Ferrite Recording Ferrites for Microwave Applications-Radio and TV Applications as discussed by the authors Magnetic Measurements on Ferrite Materials and Components.
Abstract: Basics of Magnetism-Source of Magnetic Effect.- The Magnetization in Domains and Bulk Materials.- AC Properties of Ferrites.- Crystal Structure of Ferrites.- Chemical Aspects of Ferrites.- Microstructural Aspects of Ferrites.- Ferrite Processing.- Applications and Functions of Ferrites.- Ferrites for Permanent Magnet Applications.- Ferrite Inductors and Transformers for Low Power Applications.- Ferrites for EMI Suppression.- Ferrites for Entertainment Applications-Radio and TV.- Ferrite Transformers and Inductors at High Power.- Ferrites for Magnetic Recording.- Ferrites for Microwave Applications.- Miscellaneous Ferrite Application.- Physical, Mechanical and Thermal Aspects of Ferrites.- Magnetic Measurements on Ferrite Materials and Components.
1,146 citations
TL;DR: In this article, a summary on the physical concepts of ferrofluids, hyperthermia principal, magnetic properties and synthesis methods of nanosized ferrites is given, based on the importance of ferrite particles in ferro-fluids for hyper-thermia treatment.
612 citations
TL;DR: In this article, the emission properties of suspensions of nanocrystalline ZnO particles with different particle sizes were studied and a linear relationship between the energetic maxima of the two emission bands was found.
509 citations
TL;DR: In this article, a single-phase formation of spinel structure with cubic symmetry using X-ray diffraction (XRD) data is investigated, and the change in site preference of cations in nano-MgFe 2 O 4 is compared with its bulk counterpart.
308 citations
TL;DR: In this paper, as-synthesized ZnFe2O4 nanocrystals were synthesized via the thermal decomposition of metal−surfactant complexes, and the results demonstrate that magnetic properties of magnetic particles can be largely modified by just changing p...
Abstract: Ferromagnetic zinc ferrite nanocrystals at ambient temperature were synthesized via the thermal decomposition of metal−surfactant complexes. Characterization measurements including transmission electron microscopy and X-ray diffraction were performed for as-synthesized ZnFe2O4 particles. The sample has a relatively narrow size distribution with an average particle size of 9.8 ± 0.2 nm and standard deviation of 30%. The as-synthesized zinc ferrite nanocrystals are superparamagnetic at room temperature with a blocking temperature TB = 68 ± 2 K and a saturation magnetization MS = 65.4 emu·g-1 at T = 10 K, which are caused by the change in the inversion degree of the spinel structure. A coercive field of HC = 102 ± 5 Oe in the blocked state indicates small particle anisotropy, although evidence of surface spin canting was inferred from magnetization data in the as-synthesized ZnFe2O4 nanocrystals. Our results demonstrate that magnetic properties of magnetic particles can be largely modified by just changing p...
296 citations