• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.213-219
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• 1994

The formations of spinel and colors of ZnO-Fe2O3-TiO2-SnO2 system have been researched on the basis of ZnO-Fe2O3 system. Specimens were prepared by substituting Fe3+, with Ti4+ or Sn4+ when mole ratios between Fe3+ and Ti4+ or between Fe3+ and Sn4+ were 0.2 mole. The reflectance measurement and X-ray diffraction analysis of the formation of spinel and the colors of there specimens were carried out. ZnO-Fe2O3 system in which Fe2O3 was substituted with SnO2 and TiO2 was formed the spinel structure of 2ZnO.TiO2, 2ZnO.SnO2, ZnO.Fe2O3. The stable stains which were colored with yellow and brown could be manufactured.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.240-248
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• 2002

$Fe_xTi_{l-x}O_2$ films (x=0.07 and 0.16) were grown by oxygen-plasma-assisted molecular beam epitaxy on rutile $TiO_2$(110). The same growth conditions were applied for both films in order to determine surface characteristics of grown films as a function of Fe composition. The films were characterized by several surface analysis techniques. The oxidation states of Ti and Fe in $Fe_xTi_{l-x}O_2$ films were found to be +4 and a mixture of +2 and +3, respectively. More $Fe^{3+}$ species exist in higher Fe doped film of $Fe_{0.16}Ti_{0.84}O_2$. The morphology of $Fe_{0.07}Ti_{0.93}O_2$ film shows tall rectangular and cylinderical islands growth on flat substrate-like surface. On the other hand, $Fe_{0.16}Ti_{0.84}O_2$ film consists of round shaped small islands showing somewhat rougher surface compared to the surface of $Fe_{0.16}Ti_{0.84}O_2$ film.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.43-48
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• 2020

Fe₂O₃ nanoparticles with the mixed structure of cubic and nanorod were synthesized by precipitation, hydrothermal, sol-gel method, etching process and heat treatment. Fe₂O₃/TiO₂ core-shell (CS) of type Fe₂O₃@TiO₂ composite was fabricated on a 20 nm nanolayer of TiO₂ coated on the surface of Fe₂O₃ nanoparticles. Fe₂O₃/TiO₂ yolk-shell (YS) composite was prepared by chemical etching and heat treatment of Fe₂O₃/TiO₂ CS nanoparticles. Physical properties of Fe₂O₃, Fe₂O₃@TiO₂ CS and Fe₂O₃@TiO₂ YS nanoparticles were characterized by FE-SEM, HR-TEM and X-ray diffraction. The solar reflectance, commission internationale de l'Elcairage (CIE) color coordinate and heat shield temperatures of Fe₂O₃, CS and YS type Fe₂O₃@TiO₂ pigments filled with poly acrylate (PA) paints were investigated by UV-Vis-NIR spectrometer and homemade heat shield temperature measuring device. The Fe₂O₃@TiO₂ YS red pigment filled PA composite exhibited excellent near infrared light reflecting performance and also reduced the heat shield temperature of 13 ℃ than that of Fe₂O₃ filled counterparts.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.202-207
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• 2009

Nanocomposite formation of metal-metal oxide systems by mechanical alloying (MA) has been investigated at room temperature. The systems we chose are the $Fe_3O_4$-M (M = AI, Ti), where pure metals are used as reducing agent. It is found that $Fe/Al_2O_3$ and $Fe/TiO_2$ nanocomposite powders in which $Al_2O_3$ and $TiO_2$ are dispersed in ${\alpha}$-Fe matrix with nano-sized grains are obtained by MA of $Fe_3O_4$ with Al and Ti for 25 and 75 hours, respectively. It is suggested that the shorter MA time for the nanocomposite formation in $Fe/Al_2O_3$ is due to a large negative heat associated with the chemical reduction of magnetite by aluminum. X-ray diffraction results show that the average grain size of ${\alpha}$-Fe in $Fe/TiO_2$ nanocomposite powders is in the range of 30 nm. The change in magnetic properties also reflects the details of the solid-state reduction of magnetite by pure metals during MA.

• Korean Journal of Materials Research
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• v.24 no.8
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• pp.423-428
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• 2014

We synthesized Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell nanowires(NWs) by means of a co-electrospinning method and demonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of the samples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained after calcination at $500^{\circ}C$ exhibited core/shell NWs consisting of $TiO_2$ in the core region and ${\alpha}-Fe_2O_3$ in the shell region. In addition, the XPS results confirmed the formation of Fe-doped $TiO_2$ by the doping effect of $Fe^{3+}$ ions into the $TiO_2$ lattice, which can affect the ferromagnetic properties in the core region. For comparison, pure ${\alpha}-Fe_2O_3$ NWs were also fabricated using an electrospinning method. With regard to the magnetic properties, the Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell NWs exhibited improved saturation magnetization(Ms) of approximately ~2.96 emu/g, which is approximately 6.1 times larger than that of pure ${\alpha}-Fe_2O_3$ NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the $TiO_2$ lattice, the size effect of the $Fe_2O3_$ nanoparticles, and the structural effect of the core-shell nanostructures.

• Elastomers and Composites
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• v.44 no.4
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• pp.408-415
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• 2009

Iron-loaded activated carbon fibers (Fe-ACF) supported titanium dioxide ($TiO_2$) photocatalyst (Fe-ACF/$TiO_2$) was synthesized using a sol-gel method. Three different types of Fe-ACF/$TiO_2$ were obtained by treatment with different precursor of Fe, and characterized using BET, SEM, XRD and EDX analysis. The photocatalytic activity of Fe-ACF/$TiO_2$ was investigated by the degradation of Rhodamine B (Rh.B) solution under UV irradiation. From the experimental results, it was revealed that Fe-ACF/$TiO_2$ composites show considerable photocatalytic ability for the removal of Rh.B by comparing non-treated ACF/$TiO_2$ composites. And photo-Fenton reaction with Fe element was incoordinately influenced due to different precursor of Fe. It clearly indicates that Fe-ACF/$TiO_2$ composites prepared using $FeCl_3$ provided the highest photo-Fenton activity, then, which was affected by pH changes on the degradation of Rh.B.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.305-314
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• 1991

This study was conducted to research the formation and the color development of NiO-ZnO-Fe2O3-TiO2-SnO2 system for the purpose of synthesizing the spinel pigments which are stable at high temperature. After preparing ZnO-Fe2O3 as a basic composition, {{{{ chi }}NiO.(l-{{{{ chi }})ZnO.Fe2O3 system, {{{{ chi }}NiO.(l-{{{{ chi }})ZnO.TiO2 system, and {{{{ chi }}NiO.(l-{{{{ chi }})ZnO.SnO2 system were prepared with {{{{ chi }}=0, 0.2, 0.5, 0.7, 1 mole ratio respectively. The manufacturing was carried out at 128$0^{\circ}C$ for 30 minutes. The reflectance measurement and the X-ray analysis of these specimens were carried out and the results were summarized as follows. 1. In the specimens which included NiO, it was difficult for the spinel structure to be formed. 2. As increasing the contents of NiO and Fe2O3, all the groups which were yellow or green colored changed to brown. 3. NiO-ZnO-Fe2O3 system and NiO-ZnO-TiO2 system formed the spinel structure and the illmenite structure appeared in NiO-TiO2 system.

• Resources Recycling
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• v.28 no.3
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• pp.45-52
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• 2019

$TiO_2$ as a raw material for producing titanium can be produced by carbon reduction of natural ilmenite ores over 1823 K and acid leaching of the obtained titanium-rich slag. However, the conventional process can cause very high energy consumption and a large amount of leaching residues. In the present study, we proposed the sulfurization of $FeTiO_3$ with $Na_2SO_4$ at temperatures below 1573 K, which can separate Fe in $FeTiO_3$ as the FeS based sulfide phase and Ti as the $TiO_2-Na_2O$ based oxide phase. This study is a fundamental study for sulfurization of $FeTiO_3$ to investigate the influence of reducing atmosphere, reaction temperature and the sulfur/Fe ratio on the separability and distribution behaviors of of Fe, Ti, and Na between the oxide phase and the sulfurized phase. At 1573 K and carbon saturation condition, the Fe can be separated from $FeTiO_3$ as Fe-C-S metal and a part of FeS, and the concentration of Fe in oxide decreased to 4 mass% after sulfurization.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.99-102
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• 2009

$TiO_2$ nanotube arraysdecorated with ${\alpha}-Fe_2O_3$ were prepared by forming a nanotube-like $TiO_2$ film on a Ti sheet using an anodization process, followed by electrochemical deposition treatment to decorate hematite (${\alpha}-Fe_2O_3$) nanoparticles on the $TiO_2$ nanotube arrays. The SEM and XRD results revealed that the ${\alpha}-Fe_2O_3$ nanoparticles were homogeneously embedded on the surface of the $TiO_2$ nanotube arrays. The activity of hydrogen production by photocatalytic water decomposition for the ${\alpha}-Fe_2O_3/TiO_2$ nanotube array composite was examined under visible light irradiation.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.14-23
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• 2018

$TiO_2-coated$ cubic ${\alpha}-Fe_2O_3$ with mostly exposed (012) and (101) facets (${\alpha}-Fe_2O_3@TiO_2$) was fabricated using a hydrothermal route for the photo-Fenton degradation of tetracycline under visible light irradiation. $TiO_2$ coating could greatly affect the photocatalytic activity of ${\alpha}-Fe_2O_3@TiO_2$. Compared with cubic ${\alpha}-Fe_2O_3$ alone for photodegradation of tetracycline, ${\alpha}-Fe_2O_3@TiO_2$ with $TiO_2$ shell of around 15 nm exhibited higher removal efficiency of tetracycline in photo-Fenton system, and its durability was slightly affected after five cycle times under same conditions. It is ascribed to the well-matched interface between cubic ${\alpha}-Fe_2O_3$ core and $TiO_2$ shell, leading to the broadened light-absorption and the efficient separation of photo-generated electon-hole pairs. The $^{\bullet}OH$ radicals were main responsible for the advanced photocatalytic performance of ${\alpha}-Fe_2O_3@TiO_2$ in visible-light driven degradation of tetracycline.