• 한국의류학회지
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• 제35권11호
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• pp.1297-1308
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• 2011

This research investigates the application of ZnO (zinc oxide) nanoparticles and $TiO_2$ (titanium dioxide) nanoparticles to polypropylene nonwoven fabrics via an electrospinning technique for the development of textile materials that can decompose harmful gases. To fabricate uniform ZnO nanocomposite fibers, two types of ZnO nanoparticles were applied. Colloidal $TiO_2$ nanoparticles were chosen to fabricate $TiO_2$ nano- composite fibers. ZnO/poly(vinyl alcohol) (PVA) and $TiO_2$/PVA nanocomposite fibers were electrospun under a variety of conditions that include various feed rates, electric voltages, and capillary diameters. The morphology of electrospun nanocomposite fibers was examined with a field-emission scanning electron micro- scope and a transmission electron microscope. Decomposition efficiency of gaseous materials (formaldehyde, ammonia, toluene, benzene, nitrogen dioxide, sulfur dioxide) by nanocomposite fiber webs with 3wt% nano-particles (ZnO or $TiO_2$) and 7$g/m^2$ web area density was assessed. This study shows that ZnO nanoparticles in colloid were more suitable for fabricating nanocomposite fibers in which nanoparticles are evenly dispersed than in powder. A heat treatment was applied to water-soluble PVA nanofiber webs in order to stabilize the electrospun nanocomposite fibrous structure against dissolution in water. ZnO/PVA and $TiO_2$/PVA nanofiber webs exhibited a range of degradation efficiency for different types of gases. For nitrogen dioxide, the degradation efficiency was 92.2% for ZnO nanocomposite fiber web and 87% for $TiO_2$ nanocomposite fiber web after 20 hours of UV light irradiation. The results indicate that ZnO/PVA and $TiO_2$/PVA nano- composite fiber webs have possible uses in functional textiles that can decompose harmful gases.

• 한국재료학회지
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• 제7권4호
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• pp.354-360
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• 1997

페르브스카이트 구조를 갖는 CaTiO$_{3}$-La(Zn$_{1}$2/Ti$_{1}$2)O$_{3}$계에서 소결 온도와 소결 시간의 증가에 따른 ZnO의 휘발과 이에 따른 고주파 유전 특성에 대하여 조사하였다. 시편 내부를 WDS 분석한 결과 위치에 따른 ZnO의 농도차를 관찰할 수 있었고, 시편의 두께를 달리하여 Qxf$_{o}$ 값을 조사한 결과 ZnO가 많이 휘발된 가장자리에서 더 높은 Qxf$_{o}$ 값을 얻을 수 있었다. 0.535CaTiO$_{3}$-0. 465La(Zn$_{1}$2/Ti$_{1}$2/)O$_{3}$몰비로 155$0^{\circ}C$, 2시간동안 합성한 결과 소결 밀도 5.31g/㎤, 유전율 50, Qxf$_{0}$34,000, 온도계수 +8ppm/$^{\circ}C$의 고주파 유전 특성을 갖는 소결체를 얻을 수 있었다.

• 한국세라믹학회지
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• 제26권2호
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• pp.258-266
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• 1989

The effects of grain size and dopant ZnO on the photoelectrochemical conversion in TiO2 ceramic electrodes have been investigated. The photocurrent increases with increasing grain size in the undoped TiO2 ceramic electrode. In ZnO-doped TiO2 electrodes, the photocurrent decreases with increasing ZnO up to 0.4 wt% due to decrease of donor concentration, and then with further addition of ZnO, photocurrent increases according to the formation of second phase. However, the photoresponse appears at wavelength of 420nm, which is very close to the energy band gap of TiO2, regardless of grain size and amount of ZnO.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.103-106
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• 1997

The electrical properties and the sensing properties of ZnO-TiO$_2$ composites were investigated by using the complex impedance measurement and voltage-current source and measurement unit. In air, the electrical conductivity of TiO$_2$ added ZnO increase with increasing the content of TiO$_2$ and the relative dielectric constants for 3, 5 and 7mol% TiO$_2$ added ZnO are 7, 13 and 120, respectively. In 3000ppm CO gas, the relative dielectric constants for 3, 5mol% TiO$_2$ added ZnO are 25, 28, respectively.

• Environmental Analysis Health and Toxicology
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• 제24권4호
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• pp.333-339
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• 2009

In this study, we investigated the biological toxicity of nano-scale Zn (0.1, 0.5, and 1 mol%)-doped $TiO_2$ and pure $TiO_2$ nanoparticles using zebrafish embryogenesis as our model organism. Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method for the insertion of zinc into the $TiO_2$ framework. The characters of Zn-doped $TiO_2$ (0.1%, 0.5%, 1%Zn) and pure $TiO_2$ were about 7~8 nm. These sizes were smaller than 100~200 nm of $TiO_2$ was prepared using the sol-gel method. Particularly, in this study, we found no significant biological toxicity in the hatching rate and abnormal rate under expose pure $TiO_2$ and Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method of zebrafish. It was different from the biological damage under $TiO_2$ nanoparticles were prepared using sol-gel method. We assessed that the damage was not linked to the particle's nanometer size, but rather due to the prepare method. Moreover, $TiO_2$ nanoparticles were prepared using a hydrothermal method were not shown to cause cytotoxic effects, like apoptosis and necrosis, that are the major markers of toxicity in organisms exposed to nanomaterials. Therefore, there is some relationship with biological toxicity of nanoparticles and the prepare method of nanometer size particles.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.217-217
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• 2010

산화물유전체/금속/산화물유전체(D/M/D) 구조의 투명전극은 우수한 통전성과 투광성을 갖는 동시에 근적외선 및 전자파 차폐가 가능하여 각종 디스플레이 장치로의 응용을 위해 많은 연구가 진행 중이다. 이러한 구조의 다층막의 경우 금속층과 산화물층간 계면에서의 산소확산으로 인한 광학적, 전기적 특성 저하가 문제가 되고 있다. 본 연구에서는 층간 산소확산방지를 통해 다층막의 전기적 특성을 개선하기 위해 $TiO_2$/Ag/$TiO_2$, $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ 구조의 다층막을 DC/RF 마그네트론 스퍼터를 이용하여 제조하여 ZnS 박막이 다층막의 특성에 미치는 영향을 비교 평가하였다. 제조된 박막의 전기적, 광학적, 계면 특성을 4-point probe, Spctrophotometer, AES을 이용하여 분석하였으며 PDP필터용 전극으로의 적용 가능성을 평가하였다.

• 대한금속재료학회지
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• 제56권12호
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• pp.900-909
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• 2018

A $ZnO/TiO_2$ photocatalyst decorated with PbS quantum dots (QDs) was synthesized to achieve high photocatalytic efficiency for the decomposition of dye in aqueous media. A $TiO_2$ porous layer, as a precursor photocatalyst, was fabricated using micro-arc oxidation, and exhibited irregular porous cells with anatase and rutile crystalline structures. Then, a ZnO-deposited $TiO_2$ catalyst was fabricated using a zinc acetate solution, and PbS QDs were uniformly deposited on the surface of the $ZnO/TiO_2$ photocatalyst using the successive ionic layer adsorption and reaction (SILAR) technique. For the PbS $QDs/ZnO/TiO_2$ photocatalyst, ZnO and PbS nanoparticles are uniformly precipitated on the $TiO_2$ surface. However, the diameters of the PbS particles were very fine, and their shape and distribution were relatively more homogeneous compared to the ZnO particles on the $TiO_2$ surface. The PbS QDs on the $TiO_2$ surface can induce changes in band gap energy due to the quantum confinement effect. The effective band gap of the PbS QDs was calculated to be 1.43 eV. To evaluate their photocatalytic properties, Aniline blue decomposition tests were performed. The presence of ZnO and PbS nanoparticles on the $TiO_2$ catalysts enhanced photoactivity by improving the absorption of visible light. The PbS $QDs/ZnO/TiO_2$ heterojunction photocatalyst showed a higher Aniline blue decomposition rate and photocatalytic activity, due to the quantum size effect of the PbS nanoparticles, and the more efficient transport of charge carriers.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.366-366
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• 2011

이성분 산화물인 ZnO/$TiO_2$ core-shell 나노입자는 core-shell 구조의 특성과 이성분 산화물의 상호작용에 의해서 염료감응형 태양전지의 효율향상을 기대할 수 있다. Znic acetate($Zn_2(CH_3COO)$)와 Titanium(IV) butoxide($Ti(OBu)_4$)를 이용하여 ZnO 나노입자를 수열합성하고 그 주의에 $TiO_2$을 가수분해 반응을 이용하여 둘러싸는 core-shell형태의 물질을 합성하였다. 그 이후 결정성 및 유기물 제거를 위해서 4시간 동안 고온에서 소성하였다. SEM 결과에 따르면 소성 온도를 600도까지 증가시키면 ZnO의 경우 나노입자의 크기가 증가하는 경향을 확인하였다. 하지만 core-shell의 경우는 ZnO의 뭉침현상을 $TiO_2$이 방해하여 초기합성된 크기와 동일한 크기를 유지하는 것을 확인하였다. 또한 XRD 결과에 따르면 주변에 형성된 $TiO_2$ 이외에 $Zn_2TiO_4$의 spinel 구조를 가지는 물질이 합성되는 것을 확인할 수 있었다. 합성된 core-shell 구조의 나노입자는 약 40~50 nm의 크기를 가지고 600도에서 소성된 입자의 경우 산소 정공이 거의 없는 약 3 eV의 밴드갭을 가지는 물질로 합성이 되었다. Core-shell 나노입자의 경우 염료 감응형 태양전지의 반도체 물질로 응용 가능할 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.243-247
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• 2012

Photocatalysis has been applied to decompose the waste and toxic materials produced in daily life and in the global environment. Pure $TiO_2$ (Zn-$TiO_2$-0) and Zn-doped $TiO_2$ (Zn-$TiO_2$-x, x = 3-10 mol %) samples were synthesized using a novel sol-gel and ammonia-evaporation method. The Zn-doped $TiO_2$ samples showed high photocatalytic activity for the degradation of methylene blue (MB). The physicochemical properties of the samples were investigated using XRD, SEM, ICP, DLS and BET methods. In addition, the most important measurement of photocatalytic ability was investigated by a UV-vis spectrophotometer. The effects of the mol % of zinc ion doping in $TiO_2$ on photocatalytic activity were studied. Among the mol % Zn ions investigated, the Zn-$TiO_2$-9 sample showed the highest photoreactivity. This sample removed 91.4% of the MB after 4 h, while the pure $TiO_2$ only removed 46.4% of the MB.

• 대한전기학회논문지
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• 제44권8호
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• pp.1068-1074
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• 1995

Effect of (Zn$_{1}$3/Nb$_{2}$3/) $O_{2}$ addition on the phase changes and microwave dielectric properties of BaTi $O_{3}$-3Ti $O_{2}$ ceramics were investigated. Addition of (Zn$_{1}$3/Nb$_{2}$3/) $O_{2}$ to BaTi $O_{3}$-3Ti $O_{2}$ resulted in the formation of Ba $Ti_{4}$$O_{9}$, $Ba_{2}$ $Ti_{9}$ $O_{20}$, Ba(Zn$_{1}$3/Nb$_{2}$3/) $O_{3}$, and Ti $O_{2}$ phases. Ba $Ti_{4}$$O_{9}$ phase was gradually transformed to $Ba_{2}$ $Ti_{9}$ $O_{20}$. This was identified by XRD and microstructure. As the Ba $Ti_{4}$$O_{9}$ phase transformed to $Ba_{2}$ $Ti_{9}$ $O_{20}$ phase, the dielectric constant increased to 37.5. Q*f$_{o}$ value was 40000 at x=0.04, and the temperature coefficient of resonant frequency was +10ppm/.deg. C.C.. C.C.