• 열처리공학회지
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• 제22권1호
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• pp.23-26
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• 2009

Pt nanotubes with diameter of 200 nm were fabricated by simple and convenient method of Template-Wetting Process. Porous alumina membranes were prepared by 2 step anodic oxidation as the template. To improve wetting properties and lower surface energy, pt solution was mixed with polymer. Polymer was removed completely during annealing. Grain growth process of pt nanotubes during baking and furnace annealing was examined by FE-SEM and XRD.

• 전기화학회지
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• 제15권4호
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• pp.264-269
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• 2012

본 연구에서는 50 wt%에 달하는 매우 높은 Pt 담지량에서도 장기내구성이 우수한 연료전지용 Pt/MWCNT 촉매를 마이크로파를 이용한 폴리올법을 이용하여 제조하였다. X선 회절분석법과 투과전자현미경 분석결과 마이크로파 조사시간이 늘어남에 따라 Pt의 크기가 증가하였다. 마이크로파 조사시간이 10분, 20분, 30분일 경우 Pt 크기는 각각 4.1, 4.9, 8.5 nm로 나타났다. 마이크로파를 사용하지 않은 기존 폴리올 방법에 의해 제조된 촉매와 비교하였을 경우 Pt 분산도와 장기내구성이 증가한 것으로 나타났다.

• Transactions on Electrical and Electronic Materials
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• 제14권3호
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• pp.125-129
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• 2013

Composites of platinum and multiwalled carbon nanotubes (MWNTs) were prepared in various reduction conditions and characterized using cyclic voltammetry. The MWNTs were functionalized with carboxylic acid and/or hydroxyl groups in acidic solutions prior to the formation of MWNT-Pt composites. Platinum nanoparticles were deposited onto the chemically-oxidized MWNTs in 1-propanol and 1,3-propanediol. The reduction of Pt precursors in other solutions could induce differences in their morphologies in composite thin films. The morphologies of MWNTs with Pt deposited were dependent on the reduction solutions, and the electrocatalytic activities on alcohols changed accordingly. The electrochemical activities of the as-prepared MWNT-Pt thin films on common alcohols such as methanol and ethanol were investigated.

• 전기화학회지
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• 제17권1호
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• pp.18-25
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• 2014

A Pt nanoparticle-decorated multiwall carbon nanotube (Pt-MWNT) electrode was prepared on Nafion by a hot-pressing at relatively low temperature. This electrode exhibited an intricate entangled, nanoporous structure as a result of gathering highly anisotropic Pt-MWNTs. Individual Pt nanoparticles were confirmed to have a polycrystalline face-centered cubic structure with an average crystal size of around 3.5 nm. From the cyclic voltammograms for hydrogen redox reactions, the Pt-MWNT electrode was found to have a similar electrochemical behavior to polycrystalline Pt, and a specific electrochemical surface area of $2170cm^2mg^{-1}$. Upon exposure to hydrogen analyte, the Pt-MWNT/Nafion electrode demon-strated a very high sensitivity of $3.60{\mu}A\;ppm^{-1}$ and an excellent linear response over the concentration range of 100-1000 ppm. Moreover, this electrode was also evaluated in terms of response and recovery times, reproducibility, and long-term stability. Obtained results revealed good sensing performance in hydrogen detection.

• 분석과학
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• 제27권6호
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• pp.308-313
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• 2014

염료감응형 태양전지의 광전극 및 상대전극에 탄소나노튜브를 도입하여 전지의 광전기적 특성 변화를 EIS, J-V 특성곡선 및 UV-Vis 분광기를 이용하여 분석하였다. $TiO_2$ 광전극의 전기전도도 및 광전효율을 향상시키기 위해 전자전달 촉진자 역할을 하는 multi-wall carbon nanotube (MWCNT)를 $TiO_2$와 혼합하여 $TiO_2$-MWCNT 복합체를 sol-gel 연소 복합공정을 통해 제조하여 조사한 결과 0.1 wt% MWCNT를 첨가한 경우, $TiO_2$만을 사용한 경우에 비해 약 12.5%의 향상된 효율을 보였다. $TiO_2$-MWCNT 복합체에서 MWCNT가 $TiO_2$ 층의 전자이동을 향상시켜 저항을 감소하고 염료와 전자의 재결합을 감소시킨 결과로 생각된다. 그러나 0.1 wt%보다 많은 MWCNT를 첨가할 경우 광투과도 및 염료의 흡착량을 감소시켜 효율이 감소하였다. 또한 상대전극에 MWCNT와 MWCNT-Pt를 적용하였을 경우 각각의 효율은 1.2%와 4.1%로 MWCNT만 적용할 때 보다 백금이 담지된 MWCNT를 사용하였을 경우에 백금과 비슷한 효율을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.83-83
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• 2005

• 한국재료학회지
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• 제19권5호
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• pp.233-239
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• 2009

The electrocatalytic behavior of the PtCo catalyst supported on the multi-walled carbon nanotubes (MWNTs) has been evaluated and compared with commercial Pt/C catalyst in a polymer electrolyte membrane fuel cell(PEMFC). A PtCo/MWNTs electrocatalyst with a Pt:Co atomic ratio of 79:21 was synthesized and applied to a cathode of PEMFC. The structure and morphology of the synthesized PtCo/MWNTs electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. As a result of the X-ray studies, the crystal structure of a PtCo particle was determined to be a face-centered cubic(FCC) that was the same as the platinum structure. The particle size of PtCo in PtCo/MWNTs and Pt in Pt/C were 2.0 nm and 2.7 nm, respectively, which were calculated by Scherrer's formula from X-ray diffraction data. As a result we concluded that the specific surface activity of PtCo/MWNTs is superior to Pt/C's activity because of its smaller particle size. From the electrochemical impedance measurement, the membrane electrode assembly(MEA) fabricated with PtCo/MWNTs showed smaller anodic and cathodic activation losses than the MEA with Pt/C, although ohmic loss was the same as Pt/C. Finally, from the evaluation of cyclic voltammetry(CV), the unit cell using PtCo/MWNTs as the cathode electrocatalyst showed slightly higher fuel cell performance than the cell with a commercial Pt/C electrocatalyst.

• 한국재료학회지
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• 제21권3호
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• pp.138-143
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• 2011

Nanosized Pt, Pt-Ru and Pt-$CeO_2$ electrocatalysts supported on acid-treated carbon nanotube (CNT) were synthesized by microwave-assisted heating of polyol process using $H_2Cl_6Pt{\cdot}6H_2O$, $RuCl_3$, $CeCl_3$ precursors, respectively, and were characterized by XRD and TEM. And then the electrochemical activity of methanol oxidation for catalyst/CNT nanocomposite electrodes was investigated. The microwave assisted polyol process produced the nano-sized crystalline catalysts particles on CNT. The size of Pt supported on CNT was 7~12 nm but it decreased to 3~5 nm in which 10wt% sodium acetate was added as a stabilizer during the polyol process. This fine Pt catalyst particles resulted in a higher current density for Pt/CNT electrode. It was also found that 10 nm size of PtRu alloys were formed by polyol process and the onset potential decreased with Ru addition. Cyclic voltammetry analysis revealed that the $Pt_{75}Ru_{25}/CNT$ electrode had the highest electrochemical activity owing to a higher ratio of the forward to reverse anodic peak current. And the chronoamperemetry test showed that $Pt_{75}Ru_{25}$ catalyst had a good catalyst stability. The activity of Pt was also found to be improved with the addition of $CeO_2$.

• 한국분말재료학회지
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• 제26권1호
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• pp.45-48
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• 2019

Quantum dots (QDs) are an attractive material for application in solar energy conversion devices because of their unique properties including facile band-gap tuning, a high-absorption coefficient, low-cost processing, and the potential multiple exciton generation effect. Recently, highly efficient quantum dot-sensitized solar cells (QDSCs) have been developed based on CdSe, PbS, CdS, and Cu-In-Se QDs. However, for the commercialization and wide application of these QDSCs, replacing the conventional rigid glass substrates with flexible substrates is required. Here, we demonstrate flexible CISe QDSCs based on vertically aligned $TiO_2$ nanotube (NT) electrodes. The highly uniform $TiO_2$ NT electrodes are prepared by two-step anodic oxidation. Using these flexible photoanodes and semi-transparent Pt counter electrodes, we fabricate the QDSCs and examine their photovoltaic properties. In particular, photovoltaic performances are optimized by controlling the nanostructure of $TiO_2$ NT electrodes.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.185-186
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• 2009