• 한국세라믹학회지
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• 제54권2호
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• pp.137-140
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• 2017

A $TiO_2$ nanofilm was deposited on ${\alpha}-Fe_2O_3$ nanopowders using the atomic layer deposition method. The $TiO_2$ film was prepared at $300^{\circ}C$ using $Ti(N(CH_3)_2)_4$ and $H_2O$ as the precursor and reactant gas, respectively. The thickness and composition of the $TiO_2$ surface were characterized by TEM and EDS measurements. The TEM results showed that the growth rate of the film was about $0.12{\AA}/cycle$. The EDS and SAED analyses showed the presence of titanium oxide on the surface of the ${\alpha}-Fe_2O_3$ nanopowders, confirming the deposition of the $TiO_2$ nanofilm. The Zeta potential and sedimentation test results showed that the dispersibility of the coated nanopowders was higher than that of the uncoated nanopowders. This is attributed to the electrostatic repulsion between the $TiO_2$-coated layers on the surface of the ${\alpha}-Fe_2O_3$ nanopowders. The results revealed that the $TiO_2$-coated layers modified the surface characteristics of the ${\alpha}-Fe_2O_3$ nanopowders and improved their dispersibility.

• 한국분말재료학회지
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• 제12권6호
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• pp.399-405
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• 2005

Nanopowders of titanium dioxide $(TiO_2)$ incorporating the transition metal element(s) were synthesized by flame synthesis method. Single element among Fe(III), Cr(III), and Zn(II) was doped into the interior of $TiO_2$ crystal; bimetal doping of Fe and Zn was also made. The characteristics of transition-metal-doped $TiO_2$ nanopowders in the particle feature, crystallography and electronic structures were determined with various analytical tools. The chemical bond of Fe-O-Zn was confirmed to exist in the bimetal-doped $TiO_2$ nanopowders incorporating Fe-Zn. The transition element incorporated in the $TiO_2$ was attributed to affect both Ti 3d orbital and O 2p orbital by NEXAFS measurement. The bimetal-doped $TiO_2$ nanopowder showed light absorption over more wide wavelength range than the single-doped $TiO_2$ nanopowders.

• 한국가스학회지
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• 제16권6호
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• pp.143-147
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• 2012

티타니아($TiO_2$) 나노분말의 우수한 광촉매 활성은 이를 친환경 소재로서 많은 주목을 받도록 하였다. 특히, 최근 들어 이러한 $TiO_2$의 광촉매 활성을 향상시키기 위하여 $TiO_2$ 나노분말에 금속 혹은 비금속 원소를 도핑하는 방법이 널리 시도되고 있다. 화염법, 화학기상합성법, 졸-젤법, 공침법, 이온 주입법 등 다양한 방법들이 사용되고 있으며 합성법에 따라 원소들의 도핑 거동이 달라지므로 $TiO_2$의 전자구조 및 표면성질들이 합성법의 영향을 받게 되며 광촉매 활성 역시 달라진다. $TiO_2$의 광촉매 활성은 합성법 자체에 영향을 받는 것 외에 후속의 열처리에 의해서도 달라질 수 있다. 본 연구에서는 우수한 광촉매 활성을 가진 $TiO_2$ 나노분말 소재를 제조하기 위하여 화학기상합성법(chemical vapor synthesis, CVS)으로 텅스텐(W) 원소가 도핑된 $TiO_2$ 나노분말을 제조하고 물성 및 광촉매 특성을 조사하였다. 일부의 $TiO_2$ 나노분말은 $300^{\circ}C{\sim}700^{\circ}C$ 범위에서 열처리한 후 물성 및 광촉매 특성의 변화를 조사하였다.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1495-1498
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• 2008

$TiO_2$ nanopowders were synthesized by new sol-gel combustion hybrid method using acetylene black as a fuel. The dried gels exhibited autocatalytic combustion behaviour. $TiO_2$ nanopowders with an anatase structure and a narrow size distribution were obtained at 400-600 ${^{\circ}C}$. Their crystal structures were examined by powder Xray diffraction (XRD) and their morphology and crystal size were investigated by scanning electron microscopy (SEM). The crystal size of the nanopowders was found to be in the range of 15-20 nm. $TiO_2$ powders synthesized at 500 ${^{\circ}C}$ and 600 ${^{\circ}C}$ were applied to a dye solar cell. An efficiency of 5.2% for the conversion of solar energy to electricity ($J_{sc}$ = 11.79 mA/$cm^2$, $V_{oc}$ = 0.73 V, and FF = 0.58) was obtained for an AM 1.5 irradiation (100 mW/$cm^2$) using the $TiO_2$ nanopowder synthesized by the sol-gel combustion hybrid method at 500 ${^{\circ}C}$.

• 마이크로전자및패키징학회지
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• 제19권4호
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• pp.65-69
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• 2012

복합도금이란 금속 도금층을 매트릭스로 세라믹, 폴리머, 나노분말과 같은 입자를 공석시켜 경도의 향상, 내마모성, 내식성, 자기 윤활성 등의 특성을 갖는 복합 금속피막을 얻어내는 방법으로 본 연구에서는 나노입자로 $TiO_2$를 사용하여 니켈과 함께 복합도금층을 형성하였다. $TiO_2$를 첨가시킨 복합전기도금을 통해 표면저항성 향상, 광분해 효과를 기대할 수 있다. 용액조건 중 pH 변화에 따른 zeta전위를 측정하였다. 초음파처리를 통한 물리적인 방법으로 용액 중 나노분말의 응집을 최소화한 후 $TiO_2$-Ni 복합도금을 실시하였다. 최적의 도금 조건으로 $50^{\circ}C$에서 pH 3.5, 전류밀도 $40mA/cm^2$에서 가장 효과적이었으며 Ti의 함량은 $50^{\circ}C$에서 15-20 at.%로 확인되었다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.125.2-125
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• 2003

• 한국분말재료학회지
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• 제18권1호
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• pp.14-17
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• 2011

$TiO_2$ nanopowders with anatase structure were firstly prepared by controlling the pH value of a precursor solution without any heat-treatment at room temperature. The prepared $TiO_2$ nanopowders were hydrothermally treated in 10M NaOH solution at $170^{\circ}C$. Then, the samples were washed in DI water or 0.1M HCl. The $TiO_2$ nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The gas sensitivity of $TiO_2$ nanotubes for toluene gas was also investigated. The results show that $TiO_2$ nanotubes can be prepared by hydrothermal treatment. The morphology of $TiO_2$ nanotubes prepared by 0.1M HCl washing is destroyed to some extent. $TiO_2$ nanotubes with DI water washing show better sensitivity than that with 0.1M HCl washing.

• 한국분말재료학회지
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• 제25권3호
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• pp.226-231
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• 2018

F-containing $TiO_2$ nanopowders are synthesized using simple wet processes (precipitation-based and hydrothermal) from ammonium hexafluorotitanate (AHFT, $(NH_4)_2TiF_6$) as a precursor to apply as a photocatalyst for the degradation of rhodamine B (RhB). The surface properties of the prepared samples are evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results confirm that the synthesized anatase $TiO_2$ has sphere-like shapes, with numerous small nanoparticles containing fluorine on the surface. The photocatalytic activity of F-containing $TiO_2$ compared with F-free $TiO_2$ is characterized by measuring the degradation of RhB using a xenon lamp. The photocatalytic degradation of F-containing $TiO_2$ exhibits improved photocatalytic activity, based on the positive effects of adsorbed F ions on the surface.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 춘계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.61-62
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• 2006

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 춘계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.64-65
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• 2006