• 제목/요약/키워드: anatase TiO$_2$

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

  • 이서희;이창용
    • 공업화학
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    • 제29권3호
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    • pp.298-302
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    • 2018
  • 질소가 도핑된 이산화티타늄의 광촉매 특성을 알아보았다. 질소가 도핑된 이산화티타늄에 대하여 자외선 및 가시광선 분위기에서 메틸렌블루 광촉매 분해를 수행하였다. XPS 분석을 통해 제조한 $TiO_2$에서 질소(N)가 산소(O)와 치환되었음을 확인하였다. UV-Vis DRS 분석 결과 질소가 도핑된 무정형 $TiO_2$ 시료에서는 가시광선을 거의 흡수하지 않고 자외선을 흡수하는 반면 무정형/anatase 혼재 $TiO_2$ 시료의 경우 가시광선 흡수가 상당히 증가하였다. 질소가 도핑된 anatase $TiO_2$ 시료는 자외선 및 가시광선 조사에서 메틸렌블루 광분해 반응이 나타났다. 그러나 가시광선 조사에서 분해율은 자외선 조사의 분해율보다 낮았다. 무정형/anatase 혼재 $TiO_2$ 시료의 경우 자외선과 가시광선 조사에서 anatase $TiO_2$ 시료의 분해율보다 높았다. 이러한 결과는 anatase $TiO_2$ 시료에 비해 3배 정도 큰 무정형/anatase 혼재 $TiO_2$ 시료의 높은 표면적이 질소 도핑된 작은 anatase 입자와 관련이 있음을 보여준다.

졸-겔 방법으로 합성된 TiO2 상안정성에 대한 pH 및 열처리 온도의 영향 (Phase stability of TiO2 synthesized by Sol-gel Method at various pH and calcination temperatures)

  • 이재연;김용진;김대성;신효순;남산;전명표
    • 한국결정성장학회지
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    • 제31권4호
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    • pp.166-173
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    • 2021
  • TiO2의 rutile 상은 anatase 상에 비해서 고온에서 안정한 상을 형성하지만 anatase의 안정한 온도 영역은 합성조건에 따라 변화된다. 본 연구에서는 TiOSO4와 에탄올과 증류수의 혼합용매를 사용하여 Sol-gel법으로 나노 사이즈의 TiO2를 합성하여 pH 및 열처리 온도를 따른 anatase와 rutile의 상변화에 대하여 조사하였다. 제조한 TiO2의 pH(3, 5, 7, 9)와 열처리 온도(500, 600, 700, 800, 900℃) 조건을 변화시켜 anatase와 rutile의 비율 변화를 관찰하였다. XRD, FE-SEM 분석을 통해 이와 같은 변화를 관찰한 결과, 500℃에서는 anatase TiO2, 900℃에서는 rutile TiO2가 관찰되었다. 이 중간 온도인 600, 700, 800℃에서는 pH에 따라 anatase와 rutile의 비율이 변화한다. 700℃를 기준으로 pH = 3, 5는 anatase TiO2의 비율이 더 크고, pH = 7, 9는 rutile TiO2의 비율이 더 크다는 결론을 얻었다.

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

  • 이효주;이용호;박대원
    • 한국물환경학회지
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    • 제35권6호
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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.

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

  • 변종민;박천웅;김영인;김영도
    • 한국분말재료학회지
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    • 제25권3호
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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.

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

  • 하진욱
    • 한국산학기술학회논문지
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    • 제1권2호
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    • pp.57-62
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    • 2000
  • Trichloroethvlene(TCE)의 수용액 내에서 광분해 반응을 연구하였다. 광촉매 TiO₂의 표면특성은 XRD, SEM 및 BET를 사용하여 선행연구[23]에서 고찰하였으며 Aldrich TiO₂는 100% anatase, Degussa 에서 제조한 P25-TiO₂는 75% anatase와 25% rutile의 혼합구조(structure)를 가짐을 알 수 있었다. 본 연구에서는 TCE 분해반응의 최적조건을 선정하기 위하여 광촉매의 사용량, 분해반응시 혼합용액의 순환유속, TCE의 초기농도 및 광촉매 TiO₂의 구조가 광분해 반응에 미치는 영향을 자세히 고찰하였다. 실험결과 증류수 1 L를 기준으로 무게비 0.1 wt%의 광촉매를 사용하여 증류수와 TCE의 혼합용액을 200 cc/min로 순환시켰을 때 분해활성이 가장 좋음을 알 수 있었으며 일반적으로 anatase 구조가 rutile구조를 가진 광촉매 보다 높은 활성을 보였다. 특히 anatase와 rutile의 혼합구조를 가진 Degussa P25-TiO₂가 가장 좋은 활성을 보였으며 이는 작은 입자크기와 큰 비표면적에 기인한 결과로 보인다.

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

  • 박배호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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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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Epitaxial하게 증착된 rutile-$TiO_2$와 anatase-$TiO_2$ 박막의 구조적 성질과 광전 성질에 대한 연구 (Structural and photovoltaic properties of epitaxial futile and anatase filles)

  • 박배호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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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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나노구조 TiO$_2$ 용사코팅의 미세조직 제어 공정기술 개발과 광촉매 특성평가 - Part I: TiO$_2$코팅 - (Photocatalytic Property of Nano-Structured TiO$_2$ Thermal Splayed Coating - Part I: TiO$_2$ Coating -)

  • 이창훈;최한신;이창희;김형준;신동우
    • Journal of Welding and Joining
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    • 제21권4호
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    • pp.39-45
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    • 2003
  • Nano-TiO$_2$ photocatalytic coatings were deposited on the stainless steel 304(50$\times$70$\times$3mm) by the APS(Atmospheric Plasma Spraying). Photocatlytic reaction was tested in MB(methylene blue) aqueous solution. For applying nano-TiO$_2$ powders by thermal spray, the starting nano-TiO$_2$ powder with 100% anatase crystalline was agglomerated by spray drying. Plasma second gas(H$_2$) flow rate and spraying distance were used as principal process parameters which are known to control heat enthalpy(heat input). The relationship between process parameters and the characteristics of microstructure such as the anatase phase fraction and grain size of the TiO$_2$ coatings were investigated. The photo-decomposition efficiency of TiO$_2$ coatings was evaluated by the kinetics of MB aqueous solution decomposition. It was found that the TiO$_2$ coating with a lower heat input condition had a higher anatase fraction, smaller anatase grain size and a better photo-decomposition efficiency.

Crystal Structure Dependence for Reactivities of B12-TiO2 Hybrid Catalysts with Anatase and Rutile Forms

  • Shimakoshi, Hisashi;Nagami, Yoko;Hisaeda, Yoshio
    • Rapid Communication in Photoscience
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    • 제4권1호
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    • pp.9-11
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    • 2015
  • The debromination of phenethyl bromide by the $B_{12}-TiO_2$ hybrid catalyst under UV light irradiation was investigated. The catalytic efficiency was dependent on the type of $TiO_2$. The anatase form of $TiO_2$ was superior to the rutile form of $TiO_2$. The selectivity of the product was also dependent on the crystal structure of $TiO_2$, and the rutile form of $TiO_2$ showed a high selectivity for the formation of the coupling product, 2,3-diphenylbutane, when compared to that of the anatase form of $TiO_2$.

Physicochemical properties of different phases of titanium dioxide nanoparticles

  • Dong, Vu Phuong;Yoo, Hoon
    • International Journal of Oral Biology
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    • 제46권3호
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    • pp.105-110
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    • 2021
  • The physicochemical properties of crystalline titanium dioxide nanoparticles (TiO2 NPs) were investigated by comparing amorphous (amTiO2), anatase (aTiO2), metaphase of anatase-rutile (arTiO2), and rutile (rTiO2) NPs, which were prepared at various calcination temperatures (100℃, 400℃, 600℃, and 900℃). X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed that the phase-transformed TiO2 had the characteristic features of crystallinity and average size. The surface chemical properties of the crystalline phases were different in the spectral analysis. As anatase transformed to the rutile phase, the band of the hydroxyl group at 3,600-3,100 cm-1 decreased gradually, as assessed using Fourier transform infrared spectroscopy (FT-IR). For ultraviolet-visible (UV-Vis) spectra, the maximum absorbance of anatase TiO2 NPs at 309 nm was blue-shifted to 290 nm at the rutile phase with reduced absorbance. Under the electric field of capillary electrophoresis (CE), TiO2 NPs in anatase migrated and detected as a broaden peak, whereas the rutile NPs did not. In addition, anatase showed the highest photocatalytic activity in an UV-irradiated dye degradation assay in the following order: aTiO2 > arTiO2 > rTiO2. Overall, the phases of TiO2 NPs showed characteristic physicochemical properties regarding size, surface chemical properties, UV absorbance, CE migration, and photocatalytic activity.