• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.142.2-142.2
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• 2013

The effect of substrate on catalytic activity of CO oxidation with transition metal Platinum nanoparticles on doped and undoped TiO2 was investigated. Titanium dioxide was doped chemically with non-metal anions including nitrogen and fluorine. Undoped TiO2 was synthesized via simple conventional sol-gel route. Thin films of titania were developed by spin coating technique and the characterization techniques SEM, XRD, UV-Vis Absorption Spectroscopy and XPS were carried out to examine the morphology of films, crystal phase, crystallites, optical properties and elemental composition respectively. XPS analysis from doped TiO2 confirmed that the nitrogen site were interstitial whereas fluorine was doped into TiO2 lattice substitutionally. Catalytic activity systems of Pt/doped-TiO2 and Pt/undoped-TiO2 were fabricated to reveal the strong metal-support interaction effect during catalytic activity of CO oxidation reactions. By arc plasma deposition technique, platinum nanoparticles with mean size of 2.7 nm were deposited on the thin films of doped and undoped titanium dioxide. The CO oxidation was performed with 40 Torr CO and 100 Torr O2 with 620 Torr He carrier gas. Turn over frequency was observed two to three folds enhancement in case of Pt/doped TiO2 as compared to Pt/TiO2. The electronic excitation and the oxygen vacancies that were formed with the doping process were the plausible reasons for the enhancement of catalytic activity.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1275-1279
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• 2010

We have carried out the surface modification of photocatalytic $TiO_2$ with triethoxysilane through dehydrogenation reaction and characterized the modified photocatalyst by spectroscopic methods, such as FT-IR, solid-state $^{29}Si$ MAS NMR, XPS, and XRF, etc. We also examined photocatalytic activity of the immobilized photocatalytic titanium dioxide with triethoxysilane by decolorization reaction of dyes such as cong red and methylene blue under visible light. Dispersion test showed that the photocatalytic titanium dioxide immobilized with triethoxysilane group has kept higher dispersibility than titanium dioxide itself. No appreciable precipitation takes place even after standing for 24 h in the 4:6 mixture ratio of ethanol and water.

• Corrosion Science and Technology
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• 제12권5호
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• pp.203-208
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• 2013

The electrocoating for automotive bodies is pigmented with a mixture of titanium dioxide and kaolin. In this study, the effects of titanium dioxide and kaolin contents in coating on electrodeposition process, drying, and surface properties such as surface roughness, gloss, impact resistance and corrosion resistance were investigated. Titanium dioxide and kaolin in coating do not have a decisive effect on curing reaction during drying and corrosion resistance but on gloss, surface roughness, impact resistance and electrodeposition process of coating. According to its size and shape on coating surface, pigment contents increased during drying process. However, the contents of kaolin and $TiO_2$ in coating didn't affect the corrosion resistance on zinc phosphated substrate, and the curing properties.

• 한국세라믹학회지
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• 제45권6호
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• pp.324-330
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• 2008

Activated carbon/$TiO_2$ (AC/$TiO_2$) composites modified with different concentrations of Fe were prepared. The $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine activated carbon. This indicated the blocking of the micropores on the surface of AC, which was further supported by observation via SEM. XRD results showed patterns for the composites and an anatase typed titanium dioxide structure with a small part of rutile in a higher Fe concentration (> 1.0 mol/L). EDX results showed the presence of C and, O, with Ti peaks on the composites of Fe-AC/$TiO_2$ with relatively lower Ti concentration, which may be due to the higher Fe concentration incorporated into the composites. Subsequently, the photocatalytic effects on methylene blue (MB) were investigated. The improved decomposition of MB showed the combined effects of adsorptions and photodegradation. Especially, the composites modified by Fe revealed enhanced photodegradation behaviors of MB.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.929-934
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• 2011

The adsorption kinetic study of ruthenium complex, N3, onto nanoporous titanium dioxide ($TiO_2$) photoanodes has been carried out by measuring dye uptake in-situ. Three simplified kinetic models including a pseudo first-order equation, pseudo second-order equation and intraparticle diffusion equation were chosen to follow the adsorption process. Kinetic parameters, rate constant, equilibrium adsorption capacities and related coefficient coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption kinetics of N3 dye molecules onto porous $TiO_2$ obeys pseudo second-order kinetics with chemisorption being the rate determining step. Additionally the heterogeneous surface and the pore size distribution of porous $TiO_2$ adsorbents were also discussed.

• 한국분말재료학회지
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• 제17권5호
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• pp.409-414
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• 2010

Titanium dioxide ($TiO_2$), which is one of the most basic materials in our daily life, plays a key role for environment purification. We synthesized $TiO_2$ nanoparticles by the hydrolysis reactions of titanium tetraisopropoxide using $HNO_3$ as a peptizing agent or $CH_3COOH$ as a chelating agent in the sol-gel method. The powder consisted of a rod shape or a spherical shape according to the concentration and kind of acid. The physical properties of $TiO_2$ nanoparticles were investigated with X-ray diffraction, SEM, BET analysis, and UV-Vis spectrophotometer.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.425.2-425.2
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• 2014

$TiO_2$ possesses great photocatalytic properties but absorbs only UV light owing to high band gap energy (Eg = 3.2 eV). By narrowing the band gap through doping a metal ion, the photocatalytic activity can be enhanced in condition of the light of a higher than 365 nm wavelength. Main purpose for this study is to evaluate the activities of metal doped $TiO_2$ for degrading the volatile organic compounds (VOCs); p-xylene is chosen in the VOC removal test. Vanadium is selected in this study because an ionic radius of vanadium is almost the same as titanium ion and vanadium can be easily doped into $TiO_2$. V-doped $TiO_2$ was synthesized by sol-gel methods and compared with pure $TiO_2$. Pure TiO2 powder and V-doped $TiO_2$ powder were coated on glasses by spray coating method. UV-Visible spectrophotometer was used for the measurement of the band gap changes. VOC concentration degradation level was tested with using various UV light sources in an enclosed chamber. Catalytic activities of prepared samples were evaluated based on the experimental results and compared with coated pure $TiO_2$ sample.

• 접착 및 계면
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• 제24권3호
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• pp.95-99
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• 2023

본 연구에서는, 판상형의 천연 마이카에 이산화티타늄의 코팅 및 환원을 통해 라이다 인지형 검은색 소재를 제조하였으며, 이를 도료로 응용하여 라이다 실증 검증을 진행하였다. 상세히는, 졸-겔 반응을 통해 천연 마이카에 이산화티타늄을 코팅하고, 수소화붕소나트륨을 통해 검은색으로 환원하여 Black TiO₂@Mica 소재를 제조하였다. 이후, 도료로서 응용 가능성을 확인하기 위해 친수성 투명 바니시에 혼합하고 유리 기판에 분사하였다. 그 결과, 제조한 Black TiO₂@Mica 기반의 도료는 실제 검은색의 명도(L*=12.1)와 높은 근적외선 반사율(30.2 R%)을 나타내었다. 더불어, 제조한 판상형 검은색 소재는 성공적으로 라이다 센서에 인식되는 것을 확인하였다. 이는, 굴절률이 다른 천연 마이카와 이산화티타늄 간의 계면에서 빛의 반사가 일어나는 프레넬의 반사 법칙에 기인한 것이다. 본 연구 결과를 통해, 라이다 센서에 인식되는 검은색 소재를 제조함으로써 자율주행차 뿐만 아니라 로봇, 드론 등 다양한 분야에서 활용될 수 있을 것으로 기대된다.

• 한국해양공학회지
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• 제11권1호
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• pp.44-48
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• 1997

During studies of the ripening reaction of titanium oxalate, a new crystalline phase has been found. The crystal system was determined to be orthormbic with space group $C222_1$. The unit cell parameters were refined to a=10.503(2)$\AA$ b=15.509(3)$\AA$ c=9.7000(1)$\AA$. The chemical formula of the crystal is Ti$_{2}$O$_{2}$(C$_{2}$O$_{4}$)(OH)$_{2}$. H$_{2}$O. When heated to temperatures between 31$0^{\circ}C$ and 38$0^{\circ}C$, the material became amorphous. Heated above 41$0^{\circ}C$ converted it into anatase-type titanium dioxide.

• 한국재료학회지
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• 제34권4호
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• pp.202-207
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• 2024

In this study, we undertook detailed experiments to increase hydrogen production efficiency by optimizing the thickness of titanium dioxide (TiO₂) thin films. TiO₂ films were deposited on p-type silicon (Si) wafers using atomic layer deposition (ALD) technology. The main goal was to identify the optimal thickness of TiO₂ film that would maximize hydrogen production efficiency while maintaining stable operating conditions. The photoelectrochemical (PEC) properties of the TiO₂ films of different thicknesses were evaluated using open circuit potential (OCP) and linear sweep voltammetry (LSV) analysis. These techniques play a pivotal role in evaluating the electrochemical behavior and photoactivity of semiconductor materials in PEC systems. Our results showed photovoltage tended to improve with increasing thickness of TiO₂ deposition. However, this improvement was observed to plateau and eventually decline when the thickness exceeded 1.5 nm, showing a correlation between charge transfer efficiency and tunneling. On the other hand, LSV analysis showed bare Si had the greatest efficiency, and that the deposition of TiO₂ caused a positive change in the formation of photovoltage, but was not optimal. We show that oxide tunneling-capable TiO₂ film thicknesses of 1~2 nm have the potential to improve the efficiency of PEC hydrogen production systems. This study not only reveals the complex relationship between film thickness and PEC performance, but also enabled greater efficiency and set a benchmark for future research aimed at developing sustainable hydrogen production technologies.