Synthesis, structural, optical and morphological characterization ofhematite through the precipitation method: Effect of varying thenature of the base

International audienceIron oxide (a-Fe2O3) nanoparticles were synthesized using the precipitation synthesis method focusingonly on (FeCl3, 6H2O), NaOH, KOH and NH4OH as raw materials. The impact of varying the nature of thebase on the crystalline phase, size and morphology of a-Fe2O3 products was explored. XRD spectrarevealed that samples crystallize in the rhombohedral (hexagonal) system at 800 C.The TransmissionElectron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to detect themorphology of synthesized nanoparticles and specify their sizes.However, the Fourier Transform Infra-Red (FT-IR) spectroscopy has permitted the observation of vibrationband Fe-O. Raman spectroscopy was used not only to prove that we have synthesized hematitebut also to identify their phonon modes. The Thermo Gravimetric Analysis (TGA) findings allow thethermal cycle determination of samples whereas Differential Thermal Analysis (DTA) findings allow thephase transition temperature identification. Besides, the optical investigation revealed that samples havean optical gap of about 2.1 eV. Findings highlight that the nature of the agent precipitant plays a significantrole in the morphology of the products and the formation of the crystalline phase. Hematitesynthesis with the base NH4OH brought about much stronger, sharper and wider diffraction peaks of a-Fe2O3. The morphology of samples are spherical with a size of about 61 nm while the size of thenanoparticles of hematite which we have synthesized with NaOH and KOH is respectively of the order of82 and 79 nm

Synthesis, photoluminescence and Magnetic properties of iron oxide (α-Fe 2 O 3 ) nanoparticles through precipitation or hydrothermal methods

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Photocatalytic degradation of methylene blue dye by iron oxide (α-Fe2O3) nanoparticles under visible irradiation

International audienceIron oxide (α-Fe2O3) nanoparticles were precipitated from iron (III) chloride hexahydrate (FeCl3·6H2O) at the reaction temperature 80 °C for 3 h and were further calcinated at 600, 700, 750, 800 and 850 °C for 4 h. The effect of calcination temperature on the structural, morphological, optical, magnetic and photocatalytic activity was investigated. XRD data revealed a rhombohedral (hexagonal) structure with the space group R-3c in all samples. The calcination temperature was significantly influenced the particle size and morphological properties of hematite nanoparticles and the particle size was increased from 18 to 37 nm with the increased of the calcination temperature. The synthesized nanoparticles were roughly in spherical morphology was confirmed by TEM and SEM. FT-IR confirms the phase purity of the nanoparticles synthesized. Raman spectroscopy was used not only to prove that we have synthesized pure α-Fe2O3 but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: the TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1 eV and that this value varies as a function of the calcination temperature. The products exhibited the attractive magnetic properties with high saturation magnetization, which were examined by (VSM). The photocatalytic activities of the samples were studied based on the degradation of methylene blue as a model compound, where the results showed that hematite (α-Fe2O3) a good photocatalytic activity

Improved photocatalytic activities of Cu x Co 0.5-x Ni 0.5 Fe 2 O 4 nanoparticles through co-precipitation method in degrading methylene blue

International audienceWe report the synthesis of CuxCo0.5-xNi0.5Fe2O4 with x = (0.1, 0.2, 0.3, 0.4) nanoparticles using the co-precipitation method in the presence of oleic acid as a surfactant and coating material. The X-ray diffraction analysis with Rietveld refinement technique confirmed the formation of cubic phase with Fd-3m space group of all the prepared nano-ferrites. The average crystallite size varies in the range of 21–38 nm with varying concentration of copper. The lattice parameter was found to decrease with increase in copper substitution. This may be attributed to larger ionic radius of cobalt as compared to that of copper. TEM and SEM analysis showed the monodispersion and cubic-like nanostructure. Two prominent stretching bands were observed in FT-IR spectra around 400–600 cm−1. These two bands confirmed the spinel structure of the prepared nanoparticles. Raman spectroscopy is used to verify that we have synthesized ferrite spinels and determines their phonon modes. The thermal decomposition of CuxCo0.5-xNi0.5Fe2O4 was investigated by TGA∖DTA. The optical study UV–visible is used to calculate the optical band gap energies. The products exhibited the attractive magnetic properties with high saturation magnetization, which were examined by a vibrating sample magnetometer (VSM). On the other part, the photocatalytic activity of our compounds was studied using methylene blue (MB) as model organic pollutants, where the results showed that an appropriate amount of copper (Cu2+) could greatly increase the amount of hydroxyl radicals generated by the ferrite nanoparticles, which were responsible for the obvious increase in the photocatalytic activity

Photocatalytic degradation of methyl orange dye by NiFe2O4 nanoparticles under visible irradiation: effect of varying the synthesis temperature

International audienceNanoparticles of nickel ferrites (NiFe2O4) were synthesized at different temperature of synthesis (25, 50 and 80 °C) through the chemical co-precipitation method. The synthesized powders were characterized using X-ray diffraction for crystallite size and lattice parameter calculation. It reveals the presence of cubic spinel structure of ferrites with crystallite size between 29 and 41 nm. Transmission electron microscopy and scanning electron microscopy showed uniform distribution of ferrite particles with some agglomeration. The Fourier-transform infrared spectroscopy showed absorption bonds, which were assigned to the vibration of tetrahedral and octahedral complexes. Raman spectroscopy is used to verify that we have synthesized ferrite spinels and determines their phonon modes. The thermal decomposition of the NiFe2O4 was investigated by TGA/DTA. The optical study UV–visible is used to calculate the band gap energy. Magnetic measurements of the samples were carried out by means of vibrating sample magnetometer and these studies reveal that the formed nickel ferrite exhibits ferromagnetic behavior. Photoluminescence showed three bands of luminescence located at 420, 440 and 535 nm. The photocatalytic properties of nickel ferrite (NiFe2O4) nanoparticles were evaluated by studying the photodecomposition of methyl orange as organic pollutant models and showed a good photocatalytic activity

Synthesis, structural, morphological, optical and magnetic characterization of iron oxide (α-Fe 2 O 3 ) nanoparticles by precipitation method: Effect of varying the nature of precursor

International audienceα-Fe2O3 nanoparticles were prepared via a precipitation method using each of three different precursors ((FeCl3, 6H2O), (Fe (C5H7O2)3) and (Fe (NO3)3, 9H2O)). The impact of varying the nature of the precursor on crystalline phase, size and magnetic parameters of α-Fe2O3 was examined. Powder X-ray diffraction pattern disclosed rhombohedral structure. The TEM and SEM results showed that the size of α-Fe2O3 nanocrystals was between 21 and 38 nm. FT-IR confirms the phase purity of prepared compounds. Raman studies showed the phonon modes. The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. The optical investigation exhibited that samples have an optical gap of 2.1 eV. The products exhibited the attractive magnetic properties with high saturation magnetization, which were examined by a vibrating sample magnetometer (VSM)

Structural, optical and morphological characterization of Cu-doped α-Fe 2 O 3 nanoparticles synthesized through co-precipitation technique

International audiencePure and copper (Cu concentration varying from 2 to 8%) doped hematite (α-Fe2O3) nanocrystals were synthesized through co-precipitation method using simple equipment. X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR), Raman spectroscopy, Differential Thermal Analysis (DTA), Thermo Gravimetric Analysis (TGA) and Ultraviolet–Visible (UV–Vis) techniques were used to characterize the synthesized samples. XRD measurements confirm that all the prepared nanocrystals consist only in nanocrystalline hematite phase. These results along with TEM and SEM show that the size of the nanoparticles decreases with Cu-doping down to 21 nm. FT-IR confirm the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we synthesized pure and Cu-doped hematite but also to identify their phonon modes. The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. The UV–Vis absorption measurements confirm that the decrease of particle size is accompanied by a decrease in the band gap value from 2.12 eV for pure α-Fe2O3 down to 1.91 eV for 8% Cu-doped α-Fe2O3. 8% Cu-doped hematite had the smallest size, the best crystallinity and the lowest band gap

Nanocrystalline NixCo(0.5−x)Zn0.5Fe2O4 ferrites: fabrication through co-precipitation route with enhanced structural, magnetic and photo-catalytic activity

International audienceA series of Ni-substituted NixCo(0.5−x)Zn0.5Fe2O4 with x = (0.1, 0.2, 0.3, 0.4) spinel ferrites were prepared by co-precipitation method to investigate the effects of Ni compositional variation in the structural, optical, magnetic and photo-catalytic activity. The thermal decomposition of NixCo(0.5−x)Zn0.5Fe2O4 was investigated by TGA/DTA. XRD results revealed that all the samples were single-phase of cubic spinel with Fd-3m space group. The lattice constant and average particle size decreased simultaneously with the increase in Ni doping amount. TEM and SEM analysis showed the monodispersion and cubic-like nanostructure. Two prominent stretching bands were observed in FT-IR spectra around 400–600 cm−1. These two bands confirmed the spinel structure of the prepared nanoparticles. Raman spectroscopy is used to verify that we have synthesized spinel ferrites and determines their phonon modes. The optical study UV–visible is used to calculate the optical band gap energies. The products exhibited the attractive magnetic properties with high saturation magnetization, which were examined by a vibrating sample magnetometer. On the other part, the photocatalytic activity of our compounds was studied using methylene blue as model organic pollutants, where the results showed that an appropriate amount of Ni dopant could greatly increase the amount of hydroxyl radicals generated by the ferrite nanoparticles, which were responsible for the obvious increase in the photo-catalytic activity

Synthesis and characterization of Ni-doped α-Fe2O3 nanoparticles through co-precipitation method with enhanced photocatalytic activities

International audienceIn the present study, an attempt has been made for synthesis, characterization and photocatalytic application of pure and Ni-doped α-Fe2O3 (hematite) nanoparticles by chemical co-precipitation method. The synthesized products have been studied by Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR), Raman spectroscopy, Ultraviolet–Visible (UV–Vis) analysis and Vibrating Sample Magnetometer (VSM). The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. XRD measurements confirm that all the prepared nanocrystals consist only in nanocrystalline hematite phase. TEM and SEM show that the size of the nanoparticles decreases with Ni-doping. FTIR and Raman spectroscopies confirm the phase purity and the phonon modes of the synthesized nanoparticles. The UV–Vis absorption measurements confirm that the decrease of particle size is accompanied by a decrease in the band gap value from 2.02 eV for α-Fe2O3 down to 1.81 eV for 8 mol% Ni-doped α-Fe2O3. Furthermore, the magnetic properties demonstrated that all of the samples exhibited ferromagnetic behavior at room temperature. On the other part, the photocatalytic activity of Ni-doped α-Fe2O3 particles was studied using methylene blue (MB) as model organic pollutants. The 8 mol% Ni-doped α-Fe2O3 nanoparticles disclosed that the discoloration of MB reached 86% after irradiation of 140 min