• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.1951-1957
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• 2007

A new synthetic strategy based on the acid-base catalyzed sol-gel method was developed for the preparation of a series of mesoporous TiO2 nanoparticles. A key feature of the method involves a gradual change in pH (0.8- 9) during the sol-gel transition, which guarantees easy introduction of mesoporosity without relying on the well-established sonochemical or template approach. In addition, this method leads to the exclusive formation of the anatase phase stable enough to the calcination temperature up to 600 oC. The physicochemical properties of the particles in the series were characterized by various spectroscopic and analytical techniques such as wide-angle XRD, SAXRD, BET surface area, FE-SEM, TEM, FT-IR, TGA, and XPS. The photocatalytic efficiency of these materials was investigated for the oxidation of toluene under UV-irradiation. All but T-ad in the series exhibited high photocatalytic activity pushing the reaction into completion within 3 h. The reaction followed the first order kinetics, and the rate reaches as high as 3.9 × 10?2/min which exceeds the one with the commercially available Degussa P-25 by a factor of 3.2. When comparison is made among the catalysts, the reactivity increases with increase in the calcination temperature which in turn increases the crystallinity of the anatase phase, thus revealing the following rate orders: T-3 < T-4 < T-5 < T-6.

• 멤브레인
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• 제25권5호
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• pp.398-405
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• 2015

용액-확산 메커니즘에 의해 결정되는 기존의 고분자에서와는 달리, 촉진수송은 투과도와 선택도를 동시에 향상시킬 수 있는 기술이다. 본 연구에서는 은 나노입자, 폴리비닐피롤리돈, 7,7,8,8-테트라시야노퀴노디메탄으로 구성된 촉진수송 올레핀 분리막에 있어서, 메조기공 티타늄산화물($m-TiO_2$)에 대한 영향을 연구하였다. 특히 메조기공 티타늄산화물은 폴리비닐클로라이드-g-폴리옥시에틸렌 메타크릴레이트 가지형 공중합체를 템플레이트로 하여 쉽고 대량 생산이 가능한 방법으로 제조하였다. 엑스레이 회절분석에 따르면, 제조된 메조기공 티타늄산화물은 아나타제와 루타일 상의 혼합으로 구성되어 있으며, 결정의 크기가 약 16 nm 정도 되었다. 메조기공 티타늄산화물을 첨가하였을 때, 분리막의 확산도가 증가하여 혼합기체 투과도가 1.6에서 16 GPU로 증가하였고 선택도는 45에서 37로 약간 감소하였다. 메조기공 티타늄산화물이 첨가되지 않은 분리막은 장시간 성능이 유지되었으나, 메조기공 티타늄산화물이 첨가된 분리막의 경우 시간이 지남에 따라 투과도와 선택도가 감소하였다. 이는 티타늄산화물과 은 사이의 화학적 상호작용으로 은 나노입자의 올레핀 운반체로써의 활성을 감소시키기 때문으로 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제33회 하계학술대회 초록집
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• pp.375-375
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• 2007

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.400.2-400.2
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• 2016

Dye-sensitized solar cells (DSSCs) have been widely investigated as a next generation solar cell because of their simple structure and low manufacturing cost. To realize a commercially competitive technology of DSSCs, it is imperative to employ a technique to prepare nanocrystlline thin film on the flexible organic substrate, aiming at increasing the flexibility and reducing the weight as well as the overall device thickness of DSSCs. The key operation of glass-to-plastic substrates conversion is to prepare mesoporous TiO2 thin film at low temperature with a high surface area for dye adsorption and a high degree of crystallinity for fast transport of electrons. However, the electron transport in the TiO2 film synthesized at low temperature is very poor. So, in this study, TiO2 films synthesized at high temperature were transferred on the selective substrate. We fabricated DSSCs at low temperature using this method. So, we confirmed that the performance of DSSCs using TiO2 films synthesized at high temperature was improved.

• 전기학회논문지
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• 제60권3호
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• pp.584-587
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• 2011

In this work, the $TiO_2$ and $SnO_2$ thin films as blocking layers were coated directly onto the metal-mesh electrode surface to prevent unnecessary inflow of back-transfer electrons from the electrolyte ($I^-/I_3^-$) to the metal-mesh electrode. The DSCs were fabricated with working electrode of SUS mesh coated with blocking $TiO_2$ and $SnO_2$ layers, dye-attached mesoporous $TiO_2$ film, gel electrolyte and counter electrode of Pt-deposited F:$SnO_2$. From the experimental result, it was ascertained that the efficiency of metal electrode coated with $TiO_2$ by Dip-coating was superior to that of metal electrode coated with $SnO_2$ by Dip-coating and screen printing with the results of experiments. The photo-current conversion efficiency of the cell obtained from optimum fabrication condition was 3% ($V_{oc}$=0.61V, $J_{sc}$=11.64 mA/$cm^2$, ff=0.64) under AM1.5, 100 mW/$cm^2$ illumination.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1881-1884
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• 2005

• 멤브레인
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• 제21권2호
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• pp.193-200
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• 2011

원자전달 라디칼 중합(ATRP)에 의해 poly(vinyl chloride) (PVC) 주사슬과 poly(styrene sulfonic acid) (PSSA) 곁사슬로 되어있는 양쪽성 PVC-g-PSSA 가지형 공중합체를 합성하였다. PVC-g-PSSA 가지형 공중합체 고분자를 템플레이트로 사용하고 졸겔법을 적용하여, 결정성 아타네제상의 미세기공 이산화티타튬 필름을 제조하였다. $TiO_2$ 전구체인 TTIP를 친수성인 PSSA 영역과 선택적으로 작용시켜 $TiO_2$ 메조기공 필름을 성장하였으며, 이를 주사전자 현미경 (SEM)과 엑스레이회절 (XRD)분석을 통해 분석하였다. 스핀코팅 횟수와 P25 도입에 따른 염료감응 태양전지 성능을 체계적으로 분석하였다. 그 결과 준고체 고분자 전해질을 이용하였을 때, 100 mW/$cm^2$ 조건에서 에너지 변환 효율이 2.7%에 이르렀다.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1214-1218
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• 2005

Ti-HMS samples in which titanium species exist in various forms of isolated tetrahedral state, finely dispersed $TiO_2$ cluster, and some in extra-framework anatase phase were prepared via a direct synthesis route using dodecylamine (DDS) as a structure directing agent by systematically varying the titanium loadings between 2 and 50 mol% Ti/(Ti+Si) in substrate composition. Physicochemical properties of the materials were evaluated using XRD, SEM/TEM, N2 adsorption, UV-vis and XANES spectroscopies. Catalytic properties of Ti-HMS in cyclohexene and 2,6-di-tert-butyl phenol (2,6-DTBP) oxidation using aqueous $H_2O_2$, and vapor phase photocatalytic degradation of acetaldehyde were evaluated. High $H_2O_2$ selectivity was obtained in cyclohexene oxidation, and cyclohexene conversion was found primarily dependent on the amount of tetrahedrally coordinated Ti sites. For bulky 2,6-DTBP oxidation and photocatalytic oxidation of acetaldehyde, on the other hand, conversions were found dependent on the total amount of Ti sites and maintaining an uniform mesoporous structure in the catalysts was not critical for efficient catalysis.

• Journal of Photoscience
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• 제10권3호
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• pp.231-236
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• 2003

TiO$_2$ has been used as photocatalyst since two and half decades ago. The efficiency in its photocatalytic reactions has been improved by increasing the surface area of the photocatalyst by supporting fine TiO$_2$ particles on some porous materials. In this work, heteropolytungstic acid (HPA) - encapsulated into the titanium exchanged SBA-15 mesoporous materials (TiSBA-15) were prepared and characterized. Also their photocatalytic effects on decomposition of phenol were investigated and the photodecomposition rates of the phenol were observed to be increased by 2.5 8 fold, as compared to those observed in the presence of HPA-encapsulated SBA-15 or TiSBA-15 without HPA.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.282-282
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• 2013

The antimony sulfide ($Sb_2S_3$) thin films were deposited using the gas phase method which known as atomic layer deposition (ALD) on mesoporous micro-films. Tris (dimethylamido) antimony (III[$(Me_2N)_3Sb$] and hydrogensulfide ($H_2S$) were used as precursors to deposit $Sb_2S_3$. Self-terminating nature of $(Me_2N)_3Sb$ and $H_2S$ reaction were demonstrated by growth rate saturation versus precursors dosing time. Absorption spectra and extinction coefficient were investigated by UV-VIS spectroscopy. Scanning electron microscopic analysis and X-ray photoelectron spectroscopy (XPS) depth profile were employed to determine the conformal deposition.