Journal ArticleDOI
Structural, optical, magnetic and electrical properties of hematite (α-Fe 2 O 3 ) nanoparticles synthesized by two methods: polyol and precipitation
Houda Mansour,Hanen Letifi,R. Bargougui,Sonia De Almeida-Didry,B. Negulescu,Cécile Autret-Lambert,Abdellatif Gadri,Salah Ammar,Salah Ammar +8 more
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In this article, the influence of synthesis methods on the crystalline structure, morphological, optical, magnetic and electrical properties were investigated using X-ray diffraction, RAMAN spectroscopy, scanning electron microscopy, transmission electron microscope, UV-visible diffuse reflectance spectra spectra, superconducting quantum interference device and impedance spectra.Abstract:
Hematite (α-Fe2O3) nanoparticles have been successfully synthesized via two methods: (1) polyol and (2) precipitation in water. The influence of synthesis methods on the crystalline structure, morphological, optical, magnetic and electrical properties were investigated using X-ray diffraction, RAMAN spectroscopy, scanning electron microscopy, transmission electron microscopy, UV–visible diffuse reflectance spectroscopy (UV–vis DRS), superconducting quantum interference device and impedance spectroscopy. The structural properties showed that the obtained hematite α-Fe2O3 nanoparticles with two preparation methods exhibit hexagonal phase with high crystallinity and high-phase stability at room temperature. It was found that the average hematite nanoparticle size is estimated to be 36.86 nm for the sample synthesized by precipitation and 54.14 nm for the sample synthesized by polyol. Moreover, the optical properties showed that the band gap energy value of α-Fe2O3 synthesized by precipitation (2.07 eV) was higher than that of α-Fe2O3 synthesized by polyol (1.97 eV) and they showed a red shift to the visible region. Furthermore, the measurements of magnetic properties indicated a magnetization loop typical of ferromagnetic systems at room temperature. Measurements of electrical properties show higher dielectric permittivity (5.64 × 103) and relaxation phenomenon for α-Fe2O3 issued from the precipitation method than the other sample.read more
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An overview: Facet-dependent metal oxide semiconductor gas sensors
Xing Gao,Tong Zhang +1 more
TL;DR: In this article, a review of recent efforts on engineering crystal structures with exposed high-energy facets of MOS nanomaterials and their improved gas-sensitive performance is provided, focusing on six kinds of common gas sensitive MOS including ZnO, SnO, TiO2, α-Fe2O3, NiO and Cu2O.
Journal ArticleDOI
Improved size, morphology and crystallinity of hematite (α-Fe2O3) nanoparticles synthesized via the precipitation route using ferric sulfate precursor
Diaa Eldin Fouad,Chunhong Zhang,Hamdy El-Didamony,Liu Yingnan,Tadele Daniel Mekuria,Ahmer Hussain Shah,Ahmer Hussain Shah +6 more
TL;DR: In this article, the effects of precursor concentrations, from 0.05 to 0.45 µm, on the product size, morphology, crystallinity, and lumps formation were reported.
Journal ArticleDOI
Optical characteristics of iron oxide thin films prepared by spray pyrolysis technique at different substrate temperatures
TL;DR: In this paper, the influence of substrate temperature on optical properties of iron oxide thin films was studied at room temperature in the wavelength range 300-2500nm. And the absorption coefficient, optical density, the optical energy gap, Urbach energy, steepness parameter, and the electron-phonon interaction of films were evaluated and discussed.
Journal ArticleDOI
Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains
TL;DR: In this paper, the authors reported monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe2O3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticles.
Journal ArticleDOI
Effects of sono-assisted modified precipitation on the crystallinity, size, morphology, and catalytic applications of hematite (α-Fe2O3) nanoparticles: A comparative study.
Diaa Eldin Fouad,Chunhong Zhang,Tadele Daniel Mekuria,Changlong Bi,Asad A. Zaidi,Asad A. Zaidi,Ahmer Hussain Shah,Ahmer Hussain Shah +7 more
TL;DR: In this article, an ultrasonic pathway (UP) modification was introduced as a hybrid replacement for the conventionally-used magnetic stirring pathway (MP) using different precursor concentrations to improve the adsorption and catalytic properties of hematite nanoparticles.
References
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Book
Elements of X-ray diffraction
TL;DR: In this article, the authors present a chemical analysis of X-ray diffraction by Xray Spectrometry and phase-diagram Determination of single crystal structures and phase diagrams.
Journal ArticleDOI
A profile refinement method for nuclear and magnetic structures
TL;DR: In this paper, a structure refinement method was described which does not use integrated neutron powder intensities, single or overlapping, but employs directly the profile intensities obtained from step-scanning measurements of the powder diagram.
Journal ArticleDOI
Passivating surface states on water splitting hematite photoanodes with alumina overlayers
TL;DR: In this article, an ultra-thin coating of Al2O3 was applied on the surface of high-performance hematite to reduce the overpotential of the material and increase the photocurrent.
Journal ArticleDOI
α-Fe2O3 as a photocatalytic material: A review
Maneesha Mishra,Doo-Man Chun +1 more
TL;DR: In this paper, the authors reviewed the research that has been carried out to overcome these basic limitations and to enhance the photocatalytic activity of α-Fe 2 O 3.
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