• 대한환경공학회지
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• 제27권1호
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• pp.59-66
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• 2005

[ $TiO_2$ ]박막은 DC 마그네트론 스퍼터링법을 이용하여 다양한 스퍼터링 파라미터(전력 $0.6{\sim}5.2\;kw$, 기판온도 실온${\sim}350^{\circ}C$, 산소량 $0{\sim}50\;sccm$($O_2+Ar$ 90 sccm, 압력은 약 1 mtorr))를 통하여 증착되었다. TiO-N박막도 가스의 유량비를 제외하고는 $TiO_2$박막과 같은 스퍼터링 조건하에서 증착되었다. 이러한 스퍼터링 파라미터에서 증착된 박막의 전기적 특성을 분석하기 위하여 시트저항을 측정하였고, 박막의 두께(${\alpha}$-step), 표면 거칠기(AFM), 형성 조직(FE-SEM, XRD)을 분석하여 최적 스퍼터링 파라미터를 도출하였다. 최적 스퍼터링 파라미터에서 제조된($TiO_2$, TiO-N)박막을 이용하여 광활성도를 평가하기 위하여 VOCs물질 중 toluene, 반응성 염료인 Suncion Yellow를 대상 물질로 선정하여 적용성 연구를 수행하였다. 실험에서 광촉매 박막은 적용물질에 대해서 광활성을 양호하게 보였으며, 특히 TiO-N광촉매 박막은 가시광 영역에서도 최대 33%의 톨루엔(5 ppm) 제거 효율을 나타내었다.

• 공업화학
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• 제9권4호
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• pp.585-590
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• 1998

섬유상의 $Na_xTi_nO_{2n+1}$는 층상구조의 $H_2Ti_4O_9{\cdot}nH_2O$에대한 $H^+/Na^+$의 이온교환에 의해서 합성되었다. 이온교환 반응은 0.5~2.0 M NaOH 용액에서 이루어졌으며, 2.0 M NaOH의 용액에서 이온 교환할 때 73%가 치환되었다. 이 때 길이가 $10{\sim}20{\mu}m$이고 직경이 약 $0.7{\mu}m$인 비교적 균일한 형태의 섬유상을 얻을 수 있었다. 그리고 층상구조의 티탄산나트륨에 대한 상전이는 열분석을 통해 확인하였으며, 이 결과 $Na_xTi_nO_{2n+1}$ 섬유는 $200{\sim}600^{\circ}C$의 온도에서 $Na_2Ti_6O_{13}$과 $TiO_2$로 분해되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.374.2-374.2
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• 2016

Volatile organic compounds (VOCs) in the atmosphere are harmful materials which influence indoor air environment and human health. Titanium dioxide ($TiO_2$) is photocatalyst extensively used in degradation of organic compound. To improve the photocatalytic activity in the visible light region, doping with non-metals element or loading noble metals on the surface of $TiO_2$ is generally proposed. In this study, N- doped $TiO_2$ having photocatalytic activity in visible light region was attached noble metal such as Pt, Ag, Pd, Au by coupling method. Catalytic activities of Noble metal coupled $N-TiO_2$ powders were evaluated by the improvement of their photocatalytic activities and the degradation of VOC gas. A UV-Vis spectrophotometer was used to measure the diffuse reflectance spectra of coupled $N-TiO_2$ sample. The photocatlytic activities of as prepared samples were characterized by the decoloration of aqueous MB solution under Xenon light source (UV and visible light). To measure of decomposition VOCs, ethylbenzene was selected for target VOC material and the concentration was monitored under UVLED irradiation in a closed chamber system. Adjusting the initial concentration of 10~12 ppm, to evaluate the removal characteristics by using the coupled $N-TiO_2$.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1269-1274
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• 2012

A visible light responsive N, Mo co-doped $TiO_2$ were prepared by sol-gel method. X-ray diffraction, TEM, $N_2$ adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared $TiO_2$ samples. Doping restrained the phase transformation from anatase to rutile and reduced the particle sizes. The band gap was much narrowed after N, Mo co-doping. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of doped $TiO_2$ were much higher than that of neat $TiO_2$. The photocatalytic stability of N, Mo co-doped $TiO_2$ was much better than that of N doped $TiO_2$.

• 한국응용과학기술학회지
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• 제29권3호
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• pp.466-472
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• 2012

가시광선에 감응하는 광촉매를 제조하기 위하여 $TiO_2$에 질소(N)를 도핑하여 $N-TiO_2$를 제조하였다. 제조한 광촉매의 결정성, 입자 형상 및 도핑 상태는 XRD, FE-SEM 및 XPS를 이용하여 조사하였다. 제조한 광촉매의 활성 평가는 메틸렌블루의 광분해로 조사하였다. 제조한 광촉매는 anatase type이었으며, pH가 높을수록 결정화도가 향상되었다. 제조한 광촉매의 입자 크기는 pH 2.0에서 5.42 nm, pH 4.7에서 5.99 nm, pH 9.0에서 7.58 nm로, 입자 크기는 pH가 증가 할수록 약간씩 증가하였다. 광촉매의 활성은 결정화도에 비례하였다. $TiO_2$에 N를 도핑하여 제조한 $N-TiO_2$가 가시광선 하에서도 활성을 나타냈다. $TiO_2$에 도핑한 N는 격자 속에 존재하는 것이 아니라 표면에 존재하였다.

• 한국세라믹학회지
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• 제31권9호
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• pp.995-1004
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• 1994

Phase relation and microwave dielectric properties of the system BaO.(Nd1-xSmx)2O3.TiO2 (n=4, 5) were studied. With n=5 (1 : 1 : 5), Ba2Ti9O20 and TiO2 formed in case of X$\leq$0.7, and Ba2Ti9O20 and Sm2Ti2O7 formed at X=1.0 as the second phases dispersed in fine-grained orthorhombic matrix phase. With n=4 (1 : 1 : 4). on the contrary, only fine grains of an ortho-rhombic phase were observed irrespective of Nd/Sm ratio. The compositions of these two stable orthorombic phases having distinct lattic constants even with the same Nd/Sm ratio were estimated as 4BaO.5(Nd1-xSmx)2O3.18TiO2 and BaO.(Nd1-xSmx)2O3.4TiO2 with n=5 and n=4 in the system BaO.(Nd1-xSmx)2O3.TiO2, respectively. Consequently the composition BaO.(Nd1-xSmx)2O3.5TiO2 lies in the compatible triangle of 4BaO.5(Nd1-xSmx)2O3.18TiO2 and the second phases mentioned above. The microwave dielectric properties (~4 GHz) of BaO.(Nd1-xSmx)2O3.5TiO2 can be controlled effectively by adjusting Sm content : with increasing X from 0 to 0.7, both dielectric constant and the temperature coefficient of resonant frequency decreased monotonically from 82 to 65 and from 91 (ppm/$^{\circ}C$) to -19(ppm/$^{\circ}C$), respectively, while unloaded Q(Qo) remained constant at about 2,600.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1223-1225
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• 1994

The properties of $TiN/TiSi_2$ bilayer formed by a rapid thermal anneal ing is investigated when thin $SiO_2$ film exists at the Ti-Si interface. The competitive reaction for the $TiN/TiSi_2$ bilayer occurs above $600^{\circ}C$. The thickness of the $TiSi_2$ layer decreases with increasing $SiO_2$ film thickness while the TiN layer increases at the competitive reaction. The composition of TiN layer is changed to the $TiN_xO_y$ film due to the thin $SiO_2$ layer at the Ti-Si interface while the structure of the TiN and $TiSi_2$ layers was not changed.

• 한국환경과학회지
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• 제28권11호
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• pp.971-981
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• 2019

This study evaluated the photocatalytic oxidation efficiency of volatile organic compounds by $Cu_2O-TiO_2$ under visible-light irradiation. $Cu_2O-TiO_2$ was synthesized by an ultrasonic-assisted method. The XRD result indicated successful p-n type photocatalysts. However, no diffraction peaks belonging to $TiO_2$ were observed for the $Cu_2O-TiO_2$. The Uv-vis spectra result revealed that the synthesized $Cu_2O-TiO_2$ can be activated under visible-light irradiation. The FE-TEM/EDS result showed the formation of synthesized nanocomposites in the commercial P25 $TiO_2$, the undoped $TiO_2$, and $Cu_2O-TiO_2$ and componential analysis in the undoped $TiO_2$ and $Cu_2O-TiO_2$. The photocatalytic oxidation efficiencies of benzene, toluene, ethylbenzene, and o-xylene with $Cu_2O-TiO_2$ were higher than those of P25 $TiO_2$ and undoped $TiO_2$. These results indicate that the prepared $Cu_2O-TiO_2$ photocatalyst can be applied effectively to control gaseous BTEX.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.107-107
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• 2016

TiCrAlSiN films were developed in order to improve the high-temperature oxidation resistance, corrosion resistance, and mechanical properties of conventional TiN films that are widely used as hard films to protect and increase the lifetime and performance of cutting tools or die molds. In this study, a nano-multilayered TiAlCrSiN film was deposited by cathodic arc plasma deposition. It displayed relatively good oxidation resistance at $700-900^{\circ}C$, owing to the formation protective oxides of $Al_2O_3$, $Cr_2O_3$, and $SiO_2$, and semiprotective $TiO_2$. At $1000^{\circ}C$, the increased temperature led to the formation of the imperfect oxide scale that consisted primarily of the outer ($TiO_2$,$Al_2O_3$)-mixed scale and inner ($TiO_2$, $Al_2O_3$, $Cr_2O_3$)-mixed scale.