• Title, Summary, Keyword: Anatase TiO$_2$

Search Result 524, Processing Time 0.146 seconds

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
    • /
    • v.29 no.3
    • /
    • pp.298-302
    • /
    • 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 $TiO_2$.

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
    • /
    • v.25 no.3
    • /
    • pp.257-262
    • /
    • 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
    • /
    • v.35 no.6
    • /
    • pp.550-556
    • /
    • 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.

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
    • /
    • v.1 no.2
    • /
    • pp.57-62
    • /
    • 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.

  • PDF

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
    • /
    • /
    • pp.480-483
    • /
    • 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.

  • PDF

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
    • /
    • /
    • pp.480-483
    • /
    • 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

  • PDF

Photocatalytic Property of Nano-Structured TiO$_2$ Thermal Splayed Coating - Part I: TiO$_2$ Coating - (나노구조 TiO$_2$ 용사코팅의 미세조직 제어 공정기술 개발과 광촉매 특성평가 - Part I: TiO$_2$코팅 -)

  • 이창훈;최한신;이창희;김형준;신동우
    • Journal of Welding and Joining
    • /
    • v.21 no.4
    • /
    • pp.39-45
    • /
    • 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
    • /
    • v.4 no.1
    • /
    • pp.9-11
    • /
    • 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 $TiO_2$.

Electrochemical Activity of a Blue Anatase TiO2 Nanotube Array for the Oxygen Evolution Reaction in Alkaline Water Electrolysis

  • Han, Junhyeok;Choi, Hyejin;Lee, Gibaek;Tak, Yongsug;Yoon, Jeyong
    • Journal of Electrochemical Science and Technology
    • /
    • v.7 no.1
    • /
    • pp.76-81
    • /
    • 2016
  • An anatase TiO2 nanotube array (NTA) was fabricated by anodization and successive heat treatments. When the anatase TiO2 NTA was cathodically polarized, its color changed to blue, and it could be used as an electrochemically active anode for an oxygen evolution reaction (OER) in alkaline water electrolysis. The structure of the blue anatase TiO2 NTA was controlled by the anodization conditions and its catalytic activity increased with an increase of the surface area. The activity of the blue anatase TiO2 NTA gradually reduced with the continued OER because of the partial oxidation of Ti3+ to Ti4+. However, an intermittent cathodic regeneration process could significantly slow its reduction rate. The blue anatase TiO2 NTA could be an alternative anode for alkaline water electrolysis.

Preparation of Mesoporous Titanium Oxides by Template Synthesis and Phase Transition of TiO2 inside Mesoporous Silica (주형합성을 통한 메조포러스 TiO2 제조 및 실리카 메조포어 내부에서의 TiO2 상전이 거동 변화)

  • Bang, Gyeong-Min;Kim, Young-Ji;Kim, Seung Han;Choi, Yerak;Lee, In Ho;Ko, Chang Hyun
    • Korean Chemical Engineering Research
    • /
    • v.56 no.2
    • /
    • pp.261-268
    • /
    • 2018
  • To prepare mesoporous $TiO_2$ ($meso-TiO_2$) with anatase and rutile crystal structures, hydrothermal and template synthesis were used. $Meso-TiO_2$ with anatase structure was obtained by hydrothermal synthesis. The crystal structure of $meso-TiO_2$ by hydrothermal synthesis converted from anatase to rutile by simple heating at $600^{\circ}C$ and above. However, their mesopore structure collapsed due to phase transition. To prepare $meso-TiO_2$ with rutile structure, template synthesis method was applied using mesoporous silica KIT-6 as a template. Once we incorporated anatase $TiO_2$ inside mesopores of silica, the phase transition temperature of $TiO_2$ confined inside KIT-6 was much higher ($900^{\circ}C$) than that of free-standing $TiO_2$ ($600^{\circ}C$). The suppression of $TiO_2$ phase transition inside mesopores of KIT-6 is closely related with the interaction between $TiO_2$ surface and silica walls in KIT-6 because oxygen vacancy in $TiO_2$ is regarded as the starting point for phase transition. After removal of silica template by NaOH solution washing, $meso-TiO_2$ with mixed phase between anatase and rutile was obtained.