• Title, Summary, Keyword: Rutile

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Photocatalytic Degradation of a Congo red Using ZnO/rutile-$TiO_2$, ZnO, rutile-$TiO_2$ and CdS (ZnO/rutile-$TiO_2$, ZnO, rutile-$TiO_2$, CdS를 이용한 Congo red의 광 촉매 분해반응)

  • Kim, Chang Suk;Ryu, Hae-Ill
    • Analytical Science and Technology
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    • v.14 no.3
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    • pp.259-265
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    • 2001
  • Photocatalytic degradation of Congo red was performed using various semiconductors as ZnO, CdS, rutile-$TiO_2$ or mixed rutile-$TiO_2$/ZnO. The change of degradation of the dye was investigated by UV-visible spectrophotometric method. The photocatalytic action of CdS was greater than ZnO and rutile-$TiO_2$ in account of low band gap energy of CdS. The rate of photocatalytic degradation reaction increased drastically in according to increasing ratio of ZnO on mixed rutile-$TiO_2$/ZnO. These photocatalytic effect of rutile-$TiO_2$ was suppressed by more stable rutile-$TiO_2$, doping the hydrolysis product with $Zn^{2+}$ prior to calcination onto the rutile-$TiO_2$ surface.

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Comparison of OH radical generation depending on anatase to rutile ratio of TiO2 nanotube Photocatalyst (Anatase와 Rutile 결정상 비율에 따른 TiO2 nanotube의 OH radical 생성량 비교 연구)

  • Lee, Hyojoo;Lee, Yongho;Pak, Daewon
    • Journal of Korean Society on Water Environment
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    • v.35 no.6
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    • pp.550-556
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    • 2019
  • This study was carried out to improve the photocatalytic reaction of TiO2 photocatalyst. During the photocatalytic reaction, OH radicals are generated and they have an excellent oxidation capability for wastewater treatment. To evaluate the OH radicals generated according to crystallographic structure of TiO2 nanotubes photocatalyst, a probe compound, 4-Chlorobenzoic acid was monitored to evaluate OH radical. Ultraviolet light was applied for photocatalytic reaction of TiO2. The 4-Chlorobenzoic acid solution was prepared at laboratory. TiO2 nanotube was grown on titanium plate by using anodization method. The annealing temperature for TiO2 nanotube was varied from 400 to 900 ℃ and the crystal forms of the TiO2 nanotube was analyzed. Depending on annealing temperature, TiO2 nanotubes have shown different crystal forms; 100% anatase (0 % rutile), 18.4 % rutile (81.6 % anatase), 36.6 % rutile (63.4 % anatase) and 98.6% rutile (1.4% anatase). As the annealing temperature increases, the rutile ratio increases. OH radical generation from 18.4 % rutile TiO2 nanotube plate was about 3.8 times higher than before annealing and 1.4 times higher than only 100 % anatase-TiO2 nanotube. The efficiency of the 18.4% rutile TiO2 nanotube was the best in comparison to TiO2 nanotube with 18.4 %, 36.6 % and 98.6 % rutile. As a result, photocatalytic ability of 18.4 % rutile-TiO2 nanotube plate was higher than 100 % anatase-TiO2 nanotube plate.

Structural Properties of TiO₂ Films Grown by Pulsed Laser Deposition

  • 윤하섭;김성규;임훙선
    • Bulletin of the Korean Chemical Society
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    • v.18 no.6
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    • pp.640-643
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    • 1997
  • Pure titanium dioxide $(TiO_2)$ films were prepared by pulsed laser deposition on a single crystal Si(100) substrate. We have investigated the growth of crystalline titanium dioxide films with respect to substrate temperature and ambient oxygen pressure. The structural properties of the films were analyzed by X-ray diffraction. We found that the anatase as well as the rutile phases could be formed from the original rutile phase of the target $TiO_2$. At 0.75 torr of ambient oxygen pressure, the structure of $TiO_2$ film was amorphous at room temperature, anatase between 300 and 600 ℃, a mixture of anatase and rutile between 700 and 800 ℃, and only rutile at 900 ℃ and above. However, at a low ambient oxygen pressure, the rutile phase became dominant; the only rutile phase was obtained at the ambient oxygen pressure of 0.01 torr and the substrate temperature of 800 ℃. Therefore, the film structures were largely influenced by substrate temperature and ambient oxygen pressure.

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Cyclic process for the preparation of synthetic rutile and pure iron oxide from the domestic titaniferous magnetite ore (국내 부존의 함티탄자철광으로 부터 합성 rutile 및 고순도 철화산화물의 제조를 위한 순환 공정)

  • Lee, Chul-Tae;Ryoo, Young-Hong
    • Applied Chemistry for Engineering
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    • v.2 no.4
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    • pp.372-384
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    • 1991
  • The sulfation of the domestic titaniferous magnetite ore with ammonium sulfate was investigated to find a cyclic process for the production of synthetic rutile and high purity iron oxide and to test the feasibility of ammonium sulfate being an alternative sulfation agent. The proper sulfation conditions were determined to be a temperature of $425^{\circ}C$, 2.5 hours of reaction time, the weight ratio of ammonium sulfate to titaniferous magnetite : 11, and particle size or titaniferous magnetite : -250 mesh. 90.4 % of $TiO_2$ and 85.3 % of iron were extracted from the titaniferous magnetite sulfated under these conditions by the water leaching. From the leachate $TiO_2$ of 93.8 % purity as a mixture of rutile and anatase and ${\alpha}-Fe_2O_3$ of 97.6 % purity were obtained.

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Photocatalytic activity of rutile TiO2 powders coupled with anatase TiO2 nanoparticles using surfactant (계면활성제를 이용하여 anatase TiO2 나노 입자와 결합된 rutile TiO2 분말의 광촉매 특성)

  • Byun, Jong Min;Park, Chun Woong;Kim, Young In;Kim, Young Do
    • Journal of Korean Powder Metallurgy Institute
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    • v.25 no.3
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    • pp.257-262
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    • 2018
  • The coupling of two semiconducting materials is an efficient method to improve photocatalytic activity via the suppression of recombination of electron-hole pairs. In particular, the coupling between two different phases of $TiO_2$, i.e., anatase and rutile, is particularly attractive for photocatalytic activity improvement of rutile $TiO_2$ because these coupled $TiO_2$ powders can retain the benefits of $TiO_2$, one of the best photocatalysts. In this study, anatase $TiO_2$ nanoparticles are synthesized and coupled on the surface of rutile $TiO_2$ powders using a microemulsion method and heat treatment. Triton X-100, as a surfactant, is used to suppress the aggregation of anatase $TiO_2$ nanoparticles and disperse anatase $TiO_2$ nanoparticles uniformly on the surface of rutile $TiO_2$ powders. Rutile $TiO_2$ powders coupled with anatase $TiO_2$ nanoparticles are successfully prepared. Additionally, we compare the photocatalytic activity of these rutile-anatase coupled $TiO_2$ powders under ultraviolet (UV) light and demonstrate that the reason for the improvement of photocatalytic activity is microstructural.

Defect Structure and Electrical Properties of Nonstoichiometric Rutile (비양론성 Rutile에서 결함구조와 전기적 물성)

  • Kim, Myeong-Ho;Baek, Un-Gyu
    • Korean Journal of Materials Research
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    • v.6 no.12
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    • pp.1213-1220
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    • 1996
  • 산소분압과 온도변화에 따라 비양론성 rutile(TiO2-x)의 결함모델을 전기전도 측정법에 의해 연구하였다. 산소분압과 전기전도도의 상관관계에 의하면, rutile에서 주결함은 2가로 하전된 산소빈자리와 4가로 하전된 침입형 티타늄이온이다. 117$0^{\circ}C$이상의 온도에서는 침입형 Tii…이온이 지배적인 결함이었으나, 117$0^{\circ}C$이하의 낮은 산소분압대에서는 2가로 하전된 산소빈자리가 주된 결함이었다. rutile의 전기전도 실험에서 제안된 결함모델은 본 연구팀이 O18추적자 확산실험에 의해 제안하였던 결과치와 일치하였다.

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A Study on the Synthesis of Rutile - Type Ceramic Pigments (Rutile계 안료의 합성에 관한 연구)

  • Eo, Hye-Jin;Lee, Byung-Ha
    • Journal of the Korean Ceramic Society
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    • v.48 no.2
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    • pp.178-182
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    • 2011
  • The Rutile - type brown pigments doped with chromium were synthesized. Samples of $Ti_{1-x}Cr_xO_2$ ($0.02{\leq}X{\leq}0.08$) were synthesized by the solid state method. Solid solution limit of Cr contents to the rutile structure and its coloration were studied. Optimum composition was investigated accordingly. The characteristics of synthesized pigments were analyzed by XRD, SEM, Raman spectroscopy and UV. As a result, single phase of Rutile was observed from $1000^{\circ}C$ by XRD. The maximum limit of solid solution was 0.06 mole $Cr_2O_3$. The glazed sample showed brown color, and the value of CIE $L^*a^*b^*$ was $L^*$ 33.27, $a^*$ 10.64, $b^*$ 20.84.

Structural and photovoltaic properties of epitaxial rutile and anatase filmes (Epitaxial하게 증착된 rutile-$TiO_2$와 anatase-$TiO_2$ 박막의 구조적 성질과 광전 성질에 대한 연구)

  • Park, Bae-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.480-483
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    • 2001
  • Epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films were grown at $800^{\circ}C$ on $Al_2O_3$ (1102) and $LaAlO_3$ (001), respectively, using pulsed laser deposition. The formation of different phases on different substrates could be qualitatively explained by the atomic arrangements at the interfaces. We also successfully deposited epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films on conductive $RuO_2$ and $La_{0.5}Sr_{0.5}CoO_{3}$ electrodes, respectively. Using a Kelvin probe, we measured the photovoltaic properties of these multilayer structures. A rutile-$TiO_2$ film grown on $RuO_2$ showed a very broad peak in the visible light region. An epitaxial anatase-$TiO_2$ film grown on $La_{0.5}Sr_{0.5}CoO_{3}$ showed a strong peak with a threshold energy of 3.05 eV.

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Selective Chlorination of Iron from Titaniferrous Magnetite in a Fluidized Bed Reactor (유동층 반응기에서 함티탄자철광의 선택염소화 반응)

  • Lee, Sang-Soon;Lee, Chul-Tae
    • Applied Chemistry for Engineering
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    • v.3 no.3
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    • pp.451-463
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    • 1992
  • A selective chlorination of titaniferrous magnetite in a fluidized bed reactor was investigated to find the optimum condition for selective removal of Fe component from low grade titaniferrours magnetite ore and to produce a rutile substitute from titaniferrous magnetite ore. The optimum chlorination condition was determined to be a temperaure of $950^{\circ}C$, 2hr of reaction time, reducting agent(petroleum coke) to titaniferrous magnetite weight ratio of 0.12, and $Cl_2$ gas velocity of 5cm/sec. Under the above mentioned condition, 99% of Fe in titaniferrous magnetite was removed and the reaction residue which became rutile substitute was identified as rutile by x-ray diffraction and was found to contain 70% $TiO_2$.

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