• Title, Summary, Keyword: Anatase

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Visible Light Induced Photocatalytic Activity of N-doped TiO2 (질소 도핑된 이산화티타늄의 가시광 광촉매 활성 연구)

  • Lee, Seo Hee;Lee, Chang-Yong
    • Applied Chemistry for Engineering
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    • v.29 no.3
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    • pp.298-302
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    • 2018
  • Photocatalytic properties of nitrogen doped titanium dioxide were investigated. Photocatalytic degradation of methylene blue under UV and visible light was carried out to characterize N-doped $TiO_2$. The result of XPS indicated that nitrogen atoms substitute for oxygen sites within the crystal structure of $TiO_2$. In the UV-Vis DRS spectra, N-doped amorphous $TiO_2$ absorbed UV light with little absorption of visible light, while the absorption of visible light of amorphous/anatase $TiO_2$ remarkably increased. Methylene blue photocatalytic degradation appeared by the irradiation of UV or visible light onto the N-doped anatase phase of $TiO_2$. However, the degradation rate of visible light was lower than that of UV light. The photocatalytic degradation rate of the amorphous/anatase $TiO_2$ sample was higher than that of the anatase $TiO_2$. These results indicate that the high surface area of amorphous/anatase $TiO_2$ sample, which was about three times larger than those of the anatase $TiO_2$ sample, may be related to small particles of N-doped anatase $TiO_2$.

The Photocatalytic Decomposition of Trichloroethylene(TCE) with $TiO_2$ ($TiO_2$광촉매를 이용한 Trichloroethylene(TCE)의 광분해 반응)

  • 하진욱
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.1 no.2
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    • pp.57-62
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    • 2000
  • The photocatalytic degradation of trichloroethylene(TCE) in water on various types of$TiO_2$ was studied. Surface properties of $TiO_2$were characterized by XRD, SEM, and BET in our previous work(23) . $TiO_2$from Aldrich has 100$\%$pure anatase, TiO$_2$from KIER has 100$\%$ pure rutile structure, and P25-TiO$_2$from Degussa has mixed structure of anatase(75$\%$) and rutile(25$\%$) . Firstly, optimum conditions for TCE degradation were examined in this study. Results showed that optimum loading amount of catalyst was 0.1 wt% and recirculation flow rate of mixture(distilled water and TCE) was 200 cc/min. Secondly, the effect of $TiO_2$structure on TCE degradation was examined. Results revealed that anatase structure generally has better photocatalytic activity than rutile structure. Especially, mixed structure(Degussa P25-$TiO_2$) has the highest activity due to small particle size and large specific surface area.

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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.

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.

Characterisation of $TiO_2$ film synthesized using titaniumtetrachlo precusor ($TiCl_3$를 이용해서 합성된 $TiO_2$ 박막의 특성)

  • 김강혁;이창근;이규환;김인수
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.111-111
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    • 2003
  • The peroxo titanic acid solution was successfully prepared using titanium trichloride as a precursor. The basic properties of the TiO2 film prepared by the solution were investigated in view of phase change, bandgap energy, crystalline size etc. The film displayed amorphous TiO$_2$ at room temperature, anatase above 281$^{\circ}C$ and a mixture of anatase and rutile at 99$0^{\circ}C$, The crystalline size increases with annealing temperatures, while the bandgap energies decrease due to the quantum size effect and the formation of rutile phase which has low bandgap energy. As a result of TG-DTA, it was found that annealing treatment at 99$0^{\circ}C$ for 2h formed a mixtures of anatase and rutile through three steps: (1) the removal of physically adsorbed water (2) the decomposition of peroxo group (3) amorphous-anatase or anatase-rutile phase transformation.

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HRTEM Study of Phase Transformation from Anatase to Rutile in Nanocrystalline $TiO_2$ Particles

  • Kim, Kyou-Hyun;Park, Hoon;Ahn, Jae-Pyoung;Lee, Jae-Chul;Park, Jong-Ku
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.466-467
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    • 2006
  • The anatase particle was facetted at the free surface and a neck formation between the anatase particles prior to the phase transformation occured. This resulted in the severe lattice distortion at the region of the interface near the neck and this can act as the nucleation sites for the phase transformation. The grain growth of rutile particles after the phase transformation grew very fast by the sweeping phenomena of grain boundary. Therfore, It leaded to the microstructure without the rutile phase located in anatase particle.

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Structural Changes of Hydrous Titania by Heat-Treatment (열처리에 의한 함수 티타니아의 구조적 변화)

  • Choe, Byeong-Cheol;Lee, Mun-Ho
    • Korean Journal of Materials Research
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    • v.4 no.4
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    • pp.477-482
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    • 1994
  • Structural changes of hydrous titania by heat-treatment was investigated with XRD, TEM, FT-IR, Rarnan spectral analyses. The hydrous titania was derived from a mixed solution of titanium tetrachloride and hydrogen peroxide at $30^{\circ}C$ and pH of 9.0. The precipitate was an anatase form of titania with less-developed crystalline structure. With increasing annealing temperature ranglng up to $700^{\circ}C$, the crystallinity of anatase increased, and the particles were grown at high temperature. The rutile form of titania was developed from the anatase at $700^{\circ}C$.

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Preparation and Characterization of Cerium Doped Titanium Dioxide Nano Powder for Photocatalyst

  • Ndinda, Euphracia;Park, Hyun;Kim, Kyung Nam
    • Korean Journal of Materials Research
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    • v.24 no.1
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    • pp.33-36
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    • 2014
  • This study was aimed at synthesizing and characterizing cerium-doped titania. Cerium-doped anatase titania powders were prepared by sol-gel process, with ammonium (IV) nitrate and titanium (IV) butoxide as the raw materials. The characteristics of pure $TiO_2$ and cerium-doped $TiO_2$ were investigated by XRD, TG/DTA, FE-SEM, and UV-vis spectroscopy. The results of this study show that anatase type of $TiO_2$ was obtained in as-prepared and calcined $TiO_2$ and Ce-$TiO_2$ powder. A DTA curve was also observed as the crystallization temperature decreased with increasing cerium contents. We found that the crystallite size of the obtained anatase particles decreased from 55 nm to 25 nm and the particle size decreased with increasing cerium contents. Moreover, UV-vis spectra showed that anatase titania powders with various cerium contents effectively extend the light absorption properties to the visible region.

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

  • 박배호
    • 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 80$0^{\circ}C$ on $Al_2$O$_3$ (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 3.05 eV

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