• Title/Summary/Keyword: Mesoporous $TiO_2$

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Synthesis of Mesoporous TiO2 and Its Application to Photocatalytic Activation of Methylene Blue and E. coli

  • Kim, Eun-Young;Kim, Dong-Suk;Ahn, Byung-Tae
    • Bulletin of the Korean Chemical Society
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    • v.30 no.1
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    • pp.193-196
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    • 2009
  • Mesoporous $TiO_2$ material was synthesized from diblock copolymers with ethylene oxide chains via a sol-gel process in aqueous solution. The properties of these materials were characterized with several analytical techniques including field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), wide angle X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis. The mesoporous $TiO_2$ materials calcined at 400${^{\circ}C}$ were found to have specific surface areas 212 $m^2g^-1$, average pore sizes 6.2 nm, and their average crystal sizes were found to be 8.2 nm. The photocatalytic activity of mesoporous $TiO_2$ was characterized with UV-Vis spectroscopy, and it was found to be 5.8 times higher than that of Degussa P25 $TiO_2$ (P25). For deactivation of Escherichia coli, mesoporous $TiO_2$ also has high photocatalytic inactivity than that of P25. Such a high photocatalytic activity is explained with large surface area and small crystal size with wormhole-like mesoporous structure.

Spray pyrolysis synthesis of mesoporous TiO2 microspheres and their post modification for improved photocatalytic activity

  • Choi, Jaehyung;Yoo, Kye Sang;Kim, Jinsoo
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2480-2486
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    • 2018
  • Mesoporous $TiO_2$ microspheres were prepared by spray pyrolysis for photocatalysis. Post modification of $TiO_2$ by heat treatment was performed to optimize its photocatalytic performance. First, spherical $TiO_2$ particles with mesoporous structure were synthesized at pyrolysis temperatures of 500, 600, and $700^{\circ}C$. After characterization by XRD, SEM, and $N_2$ adsorption, a sample prepared at $500^{\circ}C$ was found to possess desirable properties for photocatalytic performance through post-modification. In methylene blue degradation, mesoporous $TiO_2$ microspheres synthesized at $500^{\circ}C$ outperformed other microspheres. Furthermore, samples obtained by spray pyrolysis at $500^{\circ}C$ were calcined at various temperatures as a post-modification process. The sample calcined at $350^{\circ}C$ showed improved photocatalytic activity due to optimal anatase crystallinity and surface area.

Visible-photoresponsive Nitrogen-Doped Mesoporous TiO2 Films for Photoelectrochemical Cells

  • Bae, Jae-Young;Yun, Tae-Kwan;Ahn, Kwang-Soon;Kim, Jae-Hong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.925-928
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    • 2010
  • Nitrogen-doped $TiO_2$ ($TiO_2$:N) nano-particles with a pure anatase crystalline structure were successfully synthesized through the hydrolysis of $TiCl_4$ in an ammonia aqueous solution. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), $N_2$-sorption, and UV-vis diffuse reflectance spectra (UV-vis DRS) techniques. The absorption edge of nitrogen-doped $TiO_2$ shifted into the visible wavelength region. The photoelectrochemical (PEC) performances were investigated for the $TiO_2$ mesoporous electrodes doped with different nitrogen concentrations. The $TiO_2$:N electrodes exhibited much higher PEC responses compared to the pure $TiO_2$ electrode because of the significantly enhanced visible-photoresponsibility of the $TiO_2$:N electrodes.

Toluene Decompositions over Al-W-incorporated Mesoporous Titanosilicates Photocatalysts

  • Lee, Ye-Ji;Kim, Young-Mi;Jeong, Ha-Rim;Yeo, Min-Kyeong;Kang, Mi-Sook
    • Bulletin of the Korean Chemical Society
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    • v.30 no.1
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    • pp.107-113
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    • 2009
  • This study investigated the decomposition activities of toluene on 10 mol% Al-W-incorporated mesoporous titano (15 mol %) silicates. The mesopore sizes observed in the transmission electron microscopy images ranged from 2.0 to 5.0 nm, and the pores were irregular on the addition of 10 mol% Al or W ions, but changed to regular hexagonal forms with the simultaneous additions of Al and W. The X-ray photon spectroscopy results showed a shift of the special peak for Ti2p in Al-incorporated mesoporous titanosilicates to a stronger binding energy compared to those of mesoporous titanosilicates and Al-incorporated mesoporous titanosilicates. Three O1s peaks in the spectra of the Al and W coexisted samples were observed at 530.5 and 531.7, 533, and 533.7eV, which were assigned to $Ti-Os\;in\;TiO_2\;and\;Ti_2O_3,\;Si-O\;in\;SiO_2\;and\;Al-O\;in\;Al_2O_3$, respectively. The toluene molecules desorbed at lower temperatures over W-incorporated mesoporous titanosilicates, and the amounts of toluene desorbed were also small; however, Al-incorporated mesoporous titanosilicates adsorbed much more toluene, particular over $Al_7.5-W_2.5-Ti_15-Si_75$. The photocatalytic decomposition of toluene was more enhanced over $Al_7.5-W_2.5-Ti_15-Si_75$ than over Al- or W-incorporated mesoporous titanosilicates only.

Synthesis of Mesoporous TiO2 Thin Films with Polypyrrole Nanoparticles by Ultrasonic-induced Polymerization (초음파 중합에 의한 polypyrrole 나노입자를 함유하는 메조포러스 TiO2 박막의 합성)

  • Jang, Kwang-Suk;Cho, Sung-Ho;Song, Myung-Geun;Kim, Jong-Duk
    • Korean Chemical Engineering Research
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    • v.46 no.4
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    • pp.777-782
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    • 2008
  • Using ultrasonic-induced polymerization of pyrrole, mesoporous $TiO_2$ thin film with polypyrrole nanoparticles was prepared. Polypyrrole nanoparticles were ultrasonically synthesized in the mother solution of mesoporous $TiO_2$ before spin-coating. The polypyrrole particles were well dispersed in the solution. After spin-coating and calcinations process, the nanocomposite films have well-organized pore channels without pore-collapse, and polypyrrole nanoparticles are well dispersed in mesoporous $TiO_2$ matrix. The pore size and light absorbance of the mesoporous nanocomposite thin films were controlled by using different template materials, and by using different amount of pyrrole monomer, respectively.

Synthesis of Li-Zr incorporated mesoporous $TiO_2$ and its application in $CO_2$ adsorption ($TiO_2$ 담지체에 합성된 Li-Zr 메조포러스 분자체 ; 이산화탄소 흡착 응용)

  • Bhagiyalakshmi, Margandan;Peng, Mei Mei;Hemalatha, Pushparaj;Ganesh, Mani;Jang, Hyun-Tae
    • Proceedings of the KAIS Fall Conference
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    • 2010.11a
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    • pp.110-114
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    • 2010
  • Li-incorporated mesoporous $TiO_2$ materials with various pore-sized istributions were synthesized by using triblockcopolymers via a sol-gel process in a queous solution. The properties of the se materials were characterized by HR-TEM, XRD, and BET analysis. All particles have spherical morphology with a diameterrange of $1-3{\mu}m$. The mesoporous $TiO_2$ materials calcined at $400^{\circ}C$ and their specific surface area, average pore size and crystallite sizes were 210 $m^2g^{-1}$, 6.4 nm and 8.8 nm respectively. The Li-incorporated mesoporous $TiO_2$ were tested for $CO_2$ adsorption and its adsorption capacity is 90mg/g. The Li-incorporated mesoporous $TiO_2$ ar eobserved to be thermally stable, recyclable and greens or bent for $CO_2$ capture. The effect of bimetallic $ZrLiTiO_2$ is also studied for $CO_2$ adsorption.

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In situ FT-IR Study of 1,2-dichlorobenzene Decomposition over VOx/Mesoporous Titania by Prepared Spray Pyrolysis (분무 열분해법을 이용해 제조된 VOx/Mesoporous Titania 상에서 1,2-dichlorobenzene의 분해반응에 대한 in situ FT-IR 연구)

  • Jeon, Jong-Ki;Jung, Kyeong Youl;Park, Young-Kwon
    • Applied Chemistry for Engineering
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    • v.22 no.5
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    • pp.582-585
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    • 2011
  • In this study, surface-adsorbed species of 1,2-dichlorobenzene (1,2-DCB) on mesoporous $V_2O_5/TiO_2$ catalysts synthesized by spray pyrolysis were investigated through the adsorption/desorption performed using in situ FT-IR cell. Also, the comparison of adsorbed species with $TiO_2$ and $V_2O_5/TiO_2$ synthesized by the incipient wetness was carried out.

Fabrication of Mesoporous Hollow TiO2 Microcapsules for Application as a DNA Separator

  • Jeon, Sang Gweon;Yang, Jin Young;Park, Keun Woo;Kim, Geon-Joong
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3583-3589
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    • 2014
  • This study evaluated a simple and useful route to the synthesis of mesoporous $TiO_2$ microcapsules with a hollow macro-core structure. A hydrophilic precursor sol containing the surfactants in the hydrophobic solvents was deposited on PMMA polymer surfaces modified by non-thermal plasma to produce mesoporous shells after calcination. The surface of the PMMA polymer spheres was coated with $NH_4F$ and CTAB to control the interfacial properties and promote the subsequent deposition of inorganic sols. These hollow type mesoporous $TiO_2$ microcapsules could be applied as an efficient substrate for the immobilization of DNA oligonucleotides.

Adsorption kinetics and isotherms of phosphate and its removal from wastewater using mesoporous titanium oxide

  • Lee, Kwanyong;Jutidamrongphan, Warangkana;Lee, Seokwon;Park, Ki Young
    • Membrane and Water Treatment
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    • v.8 no.2
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    • pp.161-169
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    • 2017
  • The adsorption of phosphate onto mesoporous $TiO_2$ was investigated in order to reduce phosphorus concentrations in wastewater and provide a potential mode of phosphorus recovery. Three equilibrium isotherms were used to optimize and properly describe phosphate adsorption ($R^2$>0.95). The maximum capacity of phosphate on the adsorbent was found to be 50.4 mg/g, which indicated that mesoporous $TiO_2$ could be an alternative to mesoporous $ZrO_2$ as an adsorbent. A pseudo-second order model was appropriately fitted with experimental data ($R^2$>0.93). Furthermore, the suitable pH for phosphate removal by $TiO_2$ was observed to be in the range of pH 3-7 in accordance with ion dissociation. In contrast, increasing the pH to produce more basic conditions noticeably disturbed the adsorption process. Moreover, the kinetics of the conducted temperature study revealed that phosphate adsorption onto the $TiO_2$ adsorbent is an exothermic process that could have spontaneously occurred and resulted in a higher randomness of the system. In this study, the maximum adsorption using real wastewater was observed at $30^{\circ}C$.

Manufacturing of mesoporous TiO2 film for dye-sensitized solar cell (염료감응형 태양전지용 나노다공질 TiO$_2$ 전극막의 제조)

  • Lee, Dong-Yoon;Koo, Bo-Kun;Lee, Won-Jae;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.308-311
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    • 2003
  • The mesoporous TiO2 film for the dye-sensitized solar cell was prepared by the spin coating using nano particle $TiO_2$ slurry. In order to obtain the good dispersion of nano size $TiO_2$ particles in slurry, the pH of solvent, the sort and quantity of solvent additive and the quantity of surfactant were adjusted. The experimental range of pH was $2\;{\sim}\;4$. The basic solvent for slurry was dilute $HNO_3$ and the solvent additives were ethylene glycol, propylene glycol and butylene glycol. The degree of particle dispersion was indirectly estimated by the viscosity of slurry and the microstructure after sintering. As results, the lower the pH of solvent was the lower the viscosity of the slurry became. The addition of ethylene glycol and propylene glycol to dilute $HNO_3$ brought about the lowering of viscosity and the enhancement of stability in slurry. The addition of surfactant lowered the viscosity of slurry. It was possible to obtain the homogeneous and uniformly dispersed mesoporous TiO2 film using the dilute HNO3 solvent of pH 2 with the addition of ethylene glycol, propylene glycol and neutral surfactant.

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