• 한국재료학회지
• /
• 제19권4호
• /
• pp.192-197
• /
• 2009

Carbon nanotubes (CNT) were used as a catalyst support where catalytically active Pd and Pt metal particles decorated the outside of the external CNT walls. In this study, Pd and Pt nanoparticles supported on $HNO_3$-treated CNT were prepared by microwave-assisted heating of the polyol process using $PdCl_2$ and $H_2PtCl_6{\codt}6H_2O$ precursors, respectively, and were then characterized by SEM, TEM, and Raman. Raman spectroscopy showed that the acid treated CNT had a higher intensity ratio of $I_D/I_G$ compared to that of non-treated CNT, indicating the formation of defects or functional groups on CNT after chemical oxidation. Microwave irradiation for total two minutes resulted in the formation of Pd and Pt nanoparticles on the acid treated CNT. The sizes of Pd and Pt nanoparticles were found to be less than 10 nm and 3 nm, respectively. Furthermore, the $SnO_2$ films doped with CNT decorated by Pd and Pt nanoparticles were prepared, and then the $NO_2$ gas response of these sensor films was evaluated under $1{\sim}5\;ppm$ $NO_2$ concentration at $200^{\circ}C$. It was found that the sensing property of the $SnO_2$ film sensor on $NO_2$ gas was greatly improved by the addition of CNT-supported Pd and Pt nanoparticles.

• 공업화학
• /
• 제23권2호
• /
• pp.153-156
• /
• 2012

본 연구에서 직접 메탄올형 연료전지용 담지 촉매의 전기 화학적 효율을 높이기 위하여 담지 촉매의 합성을 위한 2가지 다른 방법을 조사하였다. 담지 촉매에 있어서 합금을 형성하여 동시 담지하는 방법과 금속을 순차적으로 담지하는 방법을 비교하였다. 금속의 총 함량을 20 wt%를 사용하였으며, Pt-Pd의 금속비를 1 : 2로 하였다. 순환 전류-전압곡선(CVs), TEM 이미지와 XRD분석을 이용하여 두가지 다른 방법으로 제조된 촉매 간의 전기화학적 특성, 입자의 평균 크기 및 결정의 구조 변화를 비교 분석하였다. 그 결과, 순차적 금속 담지 촉매가 동시 담지 촉매보다 단위 무게당 산화전류 수치를 나타내어 보다 높은 전기활성 특성을 보였다.

• 반도체공학회 논문지
• /
• 제1권1호
• /
• pp.9-13
• /
• 2023

본 연구에서는 SnO₂ 나노입자와 Pd 금속의 이중층으로 구성된 촉매층을 갖는 AlGaN/GaN 이종접합 기반의 상온동작 수소센서를 제작하여 해당 센서의 안정성 개선 연구를 수행하였다. 제작된 센서를 고온 환경이 아닌 상온에서 수소에 노출 및 차단을 반복하며 동작 시켰을 때 시간에 따라 대기전류가 감소하는 불안정한 전류 드리프트 (current drift) 현상이 발생하였지만, 자외선 (UV) 조사를 함께 진행하면서 반복 측정을 하였을 때 해당 불안정성의 가시적인 개선 효과를 이루었다.

• 한국전기전자재료학회논문지
• /
• 제31권5호
• /
• pp.345-350
• /
• 2018

Nanomaterials have considerable potential to solve several key challenges in various electrochemical devices, such as fuel cells. However, the use of nanoparticles in high-temperature devices like solid-oxide fuel cells (SOFCs) is considered problematic because the nanostructured surface typically prepared by deposition techniques may easily coarsen and thus deactivate, especially when used in high-temperature redox conditions. Herein we report the synthesis of a self-regenerated Pd metal nanoparticle on the perovskite oxide anode surface for SOFCs that exhibit self-recovery from their degradation in redox cycle and $CH_4$ fuel running. Using Pd-doped perovskite, $La(Sr)Fe(Mn,Pd)O_3$, as an anode, fairly high maximum power densities of 0.5 and $0.2cm^{-2}$ were achieved at 1,073 K in $H_2$ and $CH_4$ respectively, despite using thick electrolyte support-type cell. Long-term stability was also examined in $CH_4$ and the redox cycle, when the anode is exposed to air. The cell with Pd-doped perovskite anode had high tolerance against re-oxidation and recovered the behavior of anodic performance from catalytic degradation. This recovery of power density can be explained by the surface segregation of Pd nanoparticles, which are self-recovered via re-oxidation and reduction. In addition, self-recovery of the anode by oxidation treatment was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

• 한국재료학회지
• /
• 제32권1호
• /
• pp.14-22
• /
• 2022

To improve light absorption ability in the visible light region and the efficiency of the charge transfer reaction, Pd nanoparticles decorated with reduced TiO₂ nanotube photocatalyst were synthesized. The reduced TiO₂ nanotube photocatalyst was fabricated by anodic oxidation of Ti plate, followed by an electrochemical reduction process using applied cathodic potential. For TiO₂ photocatalyst electrochemically reduced using an applied voltage of -1.3 V for 10 min, 38% of Ti⁴⁺ ions on TiO₂ surface were converted to Ti³⁺ ion. The formation of Ti³⁺ species leads to the decrease in the band gap energy, resulting in an increase in the light absorption ability in the visible range. To obtain better photocatalytic efficiency, Pd nanoparticles were decorated through photoreduction process on the surface of reduced TiO₂ nanotube photocatalyst (r10-TNT). The Pd nanoparticles decorated with reduced TiO₂ nanotube photocatalyst exhibited enhanced photocurrent response, and high efficiency and rate constant for aniline blue degradation; these were ascribed to the synergistic effect of the new electronic state of the TiO₂ band gap energy induced by formation of Ti³⁺ species on TiO₂, and by improvement of the charge transfer reaction.

• Macromolecular Research
• /
• 제15권1호
• /
• pp.39-43
• /
• 2007

The amphiphilic block copolymer (PEtOz-PCL) of poly(2-ethyl-2-oxazoline) (PEtOz) and poly(${\varepsilon}$-caprolactone) (PCL) formed spherical micellar structures with an average diameter of 26 nm in aqueous phase. Au and Pd nanoparticles with an average diameter of $2{\sim}3nm$ were prepared by using the PEtOz-PCL micelle consisting of a PEtOz shell and PCL core. The Au nanoparticles of PEtOz-PCL micelles in aqueous phase could be transferred into organic phase by using n-dodecanethiol. The use of the Pd-NP/PEtOz-PCL micelle as a nanoreactor for Suzuki cross-coupling reaction was investigated.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.9.1-9.1
• /
• 2011

나노입자는 벌크에 비해 월등히 큰 비표면적(surface-to-volume ratio)과 작은 사이즈에서 오는 양자효과로 인해 촉매나 나노 전자 소자 등 여러 분야에서 응용되고 있다. 특히 백금 나노입자는 수소나 메탄올의 산화, 산소환원 반응의 독보적인 촉매로서 연료전지의 산화극과 환원극의 촉매로 널리 활용되고 있다. 본 연구에서는 높은 가격의 백금의 사용량을 줄일 수 있는 합금 나노입자 촉매에 대한 연구의 일환으로 Pd, Au, Cu, Ag 등의 원소를 활용한 합금 나노입자에 대한 구조 및 열역학적 안정성에 대한 연구를 수행하였다. 다양한 합금에 대한 원자간 포텐셜을 개발하였고, 이를 기반으로 몬테카를로 및 분자동력학 시뮬레이션을 수행하여 Pd-Pt, Cu-Pt, Ag-Pt, Au-Pt 이원계 합금 나노입자의 다양한 원자 구조 및 형상에 따른 결합에너지와 열역학적 특성에 대하여 분석하였다.

• 전기전자학회논문지
• /
• 제13권4호
• /
• pp.37-42
• /
• 2009

본 연구에서는 졸겔법으로 ZnO, 수열합성법으로 $SnO_2$ 나노분말을 제조하고 이들 나노분말에 Pd, Ru 등의 촉매를 첨가하였다. MEMS 기술로 제작된 히터 및 전극 구조 위에 나노 감지 분말을 도포하여 CO and $NO_2$ 가스 센서를 제작하였다. 0.1 wt% Pd 도핑된 $SnO_2$ 가스센서와 Ru 도핑된 ZnO 가스 센서는 각각 CO 30 ppm, $NO_2$ 1 ppm의 낮은 농도에서도 높은 감지 특성을 보였다.

• 전기화학회지
• /
• 제15권3호
• /
• pp.135-148
• /
• 2012

Ionic liquids are steadily attracting interests throughout a recent decade and their application is expanding into various fields including electrochemistry due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, wide electrochemical potential window and so on. These features make ionic liquids become an alternative solution for electrodeposition of metals that cannot be electroplated in aqueous electrolytes. In this review, we classify investigated metals into three categories, which are light (Li, Mg), refractory (Ti, Ta) and noble (Pd, Pt, Au) metals, rather than covering the exhaustive list of metals and try to update the recent development in this area. In electrodeposition of light metals, granular fine Li particles were successfully obtained while the passivation of electrodeposited Mg layers is an obstacle to reversible deposition-dissolution process of Mg. In the case of refractory metals, the quality of Ta and Ti deposit particles was effectively improved with addition of LiF and pyrrole, respectively. In noble metal category, EMIM TFSA ionic liquid as an electrolyte for Au electrodeposition was proven to be effective and BMP TFSA ionic liquid developed a smooth Pd deposit. Pt nanoparticle production from ionic liquid droplet in aqueous solution can be cost-effective and display an excellent electrocatalytic activity.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1617-1621
• /
• 2012

The titanate nanotube (TNT) was hydrothermally synthesized in 10 M NaOH aqueous solution at $150^{\circ}C$ for 72 h. Titanate nanotube with high surface area (292 $m^2$/g) is a good candidate as a support for catalytic reaction or organic synthesis. Palladium nanoparticles with an average size of $ca$. 3 nm were well dispersed onto the surface of TNT nanotubes. Palladium loaded catalyst with high surface area shows a highly efficient ${\alpha}$ alkylation of ketones with primary alcohols.