• 한국재료학회지
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• 제19권3호
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• pp.142-150
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• 2009

In this paper, non-treated ACF (Activated Carbon Fiber) /$TiO_2$ and Zn-treated ACF/$TiO_2$ were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/$TiO_2$ composite contained only typical single and clear anatase forms while the Zn-treated ACF/$TiO_2$ contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the $ZnCl_2$ concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/$TiO_2$ composites. The prominent photocatalytic activity of the Zn-treated ACF/$TiO_2$ can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-$TiO_2$ and Zn-ACF.

• Korean Chemical Engineering Research
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• 제53권3호
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• pp.276-281
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• 2015

$TiO_2-SiO_2$ 나노복합소재는 자체가 화학적으로 안정할 뿐만 아니라 광학적, 열적 특성이 매우 우수하여 광화학센서, 촉매 등 다양한 분야에 적용되고 있다. 이러한 구조를 구현하는 방법으로 티타늄이 첨가된 폴리카보실란(PCS) 혼합용액을 전기방사한 후 이를 적절한 산화분위기에서 열처리하여 부직포상의 $TiO_2-SiO_2$ 나노복합섬유를 만들 수 있는데, 이는 기존의 졸겔공정에 의해 제조되는 섬유보다 더 쉽고 안정적인 방법이다. 공정 중 방사된 섬유를 산화분위기에서 $1200^{\circ}C$ 이상까지 열처리하게 되면 크리스토발라이트 기지조직 내에서 아나타제 나노결정상이 매우 균일하게 형성되었다. 또한, 열처리 후 섬유의 표면과 단면은 매우 치밀하고 매끈하였으며 10~20nm 크기의 아나타제 결정입자들이 내부에 균일하게 분포하였다.

• Elastomers and Composites
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• 제44권3호
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• pp.290-298
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• 2009

본 논문에서 Fe-활성탄소 섬유(ACF)/$TiO_2$ 복합체 광촉매를 졸-겔 방법에 의하여 제조하였다. 합성된 광촉매는 UV조사하에서 MB용액의 광분해에 사용되었다. BET 데이터는 Fe와 Ti의 여러 가지 농도를 가지고 처리된 ACF의 표면에서 흡착 특성을 보여준다. SEM 사진에서 보여지는 것처럼, 철 혼합물과 $TiO_2$는 ACF 표면에 활착되어 있음을 나타내었다. X선 분말 회절법으로부터 얻어진 결과는 복합체로부터 FeO+$TiO_2$, Anatase 및 Rutile 구조의 결정상을 나타내었다. 원소분석을 위한 EDX spectra는 Fe와 함께 C, O, Ti의 peak들이 존재함을 나타내었다. MB 분해에 대한 활성은 $TiO_2$의 광분해와 Fe의 photo-Fenton 효과로 인해 전자/hole쌍 반응으로부터 파생된 -OH 라디칼들에 의한 것으로 여겨진다.

• 대한금속재료학회지
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• 제50권3호
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• pp.201-205
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• 2012

The effects of various manganese precursors for the low-temperature selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyses. $MnO_x/TiO_2$ catalysts were prepared from three different precursors, manganese nitrate, manganese acetate(II), and manganese acetate(III), by the sol-gel method. The manganese acetate(III)-$MnO_x/TiO_2$ catalyst tended to suppress the phase transition from the anatase structure to the rutile or the brookite after calcination at $500^{\circ}C$ for 2 h. It also had a high specific surface area, which was caused by a smaller particle size and more uniform distribution than the others. The change of catalytic acid sites was confirmed by Raman and FT-IR spectroscopy and the manganese acetate(III)-$MnO_x/TiO_2$ had the strongest Lewis acid sites among them. The highest de-NOx efficiency and structural stability were achieved by using the manganese cetate(III) as a precursor, because of its high specific surface area, a large amount of anatase $TiO_2$, and the strong catalytic acidity.

• 한국재료학회지
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• 제31권10호
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• pp.552-561
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• 2021

For the purpose of manufacturing a high efficiency TiO₂ photocatalyst, B-doped TiO₂ photocatalysts are synthesized using a plasma electrolytic oxidation method in 0.5 M H₂SO₄ electrolyte with different concentrations of H₃BO₃ as additive. For the B doped TiO₂ layer fabricated from sulfuric electrolyte having a higher concentration of H₃BO₃ additive, the main XRD peaks of (101) and (200) anatase phase shift gradually toward the lower angle direction, indicating volume expansion of the TiO₂ anatase lattice by incorporation of boron, when compared with TiO₂ layers formed in sulfuric acid with lower concentration of additive. Moreover, XPS results indicate that the center of the binding energy peak of B1s increases from 191.45 eV to 191.98 eV, which suggests that most of boron atoms are doped interstitially in the TiO₂ layer rather than substitutionally. The B doped TiO₂ catalyst fabricated in sulfuric electrolyte with 1.0 M H₃BO₃ exhibits enhanced photocurrent response, and high efficiency and rate constant for dye degradation, which is ascribed to the synergistic effect of the new impurity energy band induced by introducing boron to the interstitial site and the improvement of charge transfer reaction.

• 공업화학
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• 제16권6호
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• pp.785-789
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• 2005

$TiCl_4$와 염산수용액을 사용하여 균일침전반응으로 브루카이트상과 루틸상의 혼합상 $TiO_2$ 분말을 제조하여 분말특성을 조사하였다. 분석결과로부터 순수한 루틸상과 혼합상이 합성되기 위한 침전용액의 ${Cl^-}_{total}:Ti^{+4}$의 몰 비율이 제시되었다. 또한, 혼합상이 얻어지는 조건에서는 염산의 농도가 증가할수록 브루카이트상의 부피분율이 증가하였으며, 이 분말을 열처리한 결과 브루카이트상은 루틸상으로 직접 상변화하지 않고 $800^{\circ}{\sim}850^{\circ}C$에서 아나타제상으로 상전이한 후 $1000^{\circ}C$에서 최종적으로 안정한 루틸상으로 상변화되었다.

• 한국대기환경학회지
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• 제19권1호
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• pp.57-66
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• 2003

TiO$_2$ sol was prepared by sol-gel method, and this sol was coated in ceramic and glass bead by dip-coating method. The coated catalyst was applied to degrade benzene in the gas phase by exposing to UV -lamp (365 nm) in a batch reactor. The removal efficiency of the benzene was compared by changing various conditions such as the kind of chemical additives, the coating beads (ceramic and glass), solution pH, the initial concentration of TiO$_2$ sol, UV intensity, and benzene concentration. The physical structure of TiO$_2$ sol used in this study was found to be pu-rely anatase type from XRD analysis. The results showed that ceramic bead was effective as the coating agent rath-er than glass bead. The significant change in the benzene removal efficiency of benzene did not occur with chang-ing coating frequency and the initial concentration of TiO$_2$ sol. The removal efficiency of benzene increased with increasing UV intensity, and with acidic treatment of TiO$_2$-coated ceramic bead.

• Elastomers and Composites
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• 제49권1호
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• pp.53-58
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• 2014

가시광촉매의 특성 및 가시광촉매가 코팅처리된 자동차내장재 nylon/polyester 복합섬유에 대한 VOCs의 저감에 대해 알아보았다. 가시광촉매 Weltouch의 결정구조는 아나타제상과 루타일상이 복합된 것으로 약 420nm이상의 파장을 갖는 빛에너지에서도 활성을 나타냈다. 또한 가시광촉매가 처리된 자동차내장재 nylon/polyester 복합 섬유에서 발생하는 VOCs 및 포름알데히드는 현저한 저감효과를 나타냈으며, 섬유를 25회 세탁을 행하여도 가시광촉매의 탈락없이 표면에 견고하게 부착되어 가스분해성능을 유지하는 것으로 나타나서 세탁내구성이 우수한 것을 확인하였다.

• 전기화학회지
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• 제15권3호
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• pp.149-153
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• 2012

The $Cu_2O/TiO_2$ inverse opal heterojunction arrays were developed by electrochemical deposition of $Cu_2O$ nanoparticles on $TiO_2$ inverse opal arrays. The $Cu_2O$ nanoparticles completely filled the inner pores of $TiO_2$ inverse opal film (prepared by liquid phase deposition with an average thickness of 400 nm) and covered the entire area; exhibiting high crystalline properties of anatase and cubic phase from $TiO_2$ and $Cu_2O$, respectively. From asymmetric current-voltage profile, it was noticeable that a heterojunction was well formed for charge transport from $Cu_2O$ to $TiO_2$ film resulting from the enhanced charge separation yield. In addition, increased photocurrent of 0.19 $mA/cm^2$ (versus 0.08 $mA/cm^2$ under dark condition) was obtained at -0.35 V from the heterojunction structure in the 0.5M $Na_2SO_4$ solution.

• 한국수소및신에너지학회논문집
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• 제14권1호
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• pp.8-16
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• 2003

$TiO_2$ thin films were deposited by DC reactive magnetron sputtering with variations in sputtering parameter such as Ar and $O_2$ flow rate, DC power, substrate temperature and magnetic field. Deposition rate, crystal structure, chemical bond of $TiO_2$ films on the deposition conditions were investigated by Alpha-step, X-ray Diffractometer(XRD), X-ray Photoelectron Spectroscopy(XPS). When the DC power was applied at 500watt, deposition rate of $TiO_2$ film was about 480A/min. $TiO_2$ films coated under the deposition condition of 15sccm Ar and 7~10sccm $O_2$ flow rate was only observed anatase phase. With increasing substrate temperature from RT to $300^{\circ}C$, crystal orientation of $TiO_2$ films variously became.