• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.133-133
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• 2013

For both oxygen reduction (ORR) and hydrogen oxidation reactions (HOR) of proton electrolyte membrane fuel cells (PEMFCs), alloying Pt with another transition metal usually results in a higher activity relative to pure Pt, mainly due to electronic modification of Pt and bifunctional behaviour of alloy surface for ORR and HOR, respectively. However, activity and stability are closely related to the preparation of alloy nanoparticles. Preparation conditions of alloy nanoparticles have strong influence on surface composition, oxidation state, nanoparticle size, shape, and contamination, which result from a large difference in redox priority of metal precursors, intrinsic properties of metals, increasedreactivity of nanocrystallites, and interactions with constituents for the synthesis such as solvent, stabilizer, and reducing agent, etc. Carbon-supported Pt-Ni alloy nanoparticles were prepared by the borohydride reduction method in anhydrous solvent. Pt-Ru alloy nanoparticles supported on carbon black were also prepared by the similar synthetic method to that of Pt-Ni. Since electrocatalytic reactions are strongly dependent on the surface structure of metal catalysts, the atom-leveled design of the surface structure plays a significant role in a high catalytic activity and the utilization of electrocatalysts. Therefore, surface-modified electrocatalysts have attracted much attention due to their unique structure and new electronic and electrocatalytic properties. The carbon-supported Au and Pd nanoparticles were adapted as the substrate and the successive reduction process was used for depositing Pt and PtM (M=Ru, Pd, and Rh) bimetallic elements on the surface of Au and Pd nanoparticles. Distinct features of the overlayers for electrocatalytic activities including methanol oxidation, formic acid oxidation, and oxygen reduction were investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.296-299
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• 2003

In this paper, $0.10Pb(Sb_{1/2}Sn_{1/2})O_3-0.25PbTiO_3-0.65PbZrO_3$ ceramics were fabricated by the mixed-oxide method. The sintering temperature and time were $1230^{\circ}C$ and 2[hr], respectively. The structural, dielectric and piezoelectric properties with addition of NiO were studied. The crystal structure of a specimen was rhombohedral. As a result of SEM, the average grain size were decreased with increasing the contents of NiO. But the grains of the specimens doped with 0.4wt% NiO were increased, due to deposits of excess NiO at grain boundaries in the liquid phase. Relative dielectric constant and dielectric loss of the specimen doped with 0.1wt% NiO were 701 and 0.026, respectively.

• 청정기술
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• 제19권1호
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• pp.13-21
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• 2013

다른 분율의 Cs이 포함된 Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ 촉매를 제조하여 셀룰로우스의 폴리올로의 수소화분해반응를 수행하였다. 촉매의 비표면적과 Pt의 분산도는 Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ 촉매의 Cs 함량이 증가함에 따라 증가하였다. 그러나 Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ 촉매의 Cs의 함량이 변함에도 불구하고 비슷한 폴리올 수득률을 보였다. Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ 촉매의 반응 활성은 Ni/W/SBA-15와 두 가지의 복합촉매(Pt/AC+$H_3PW_{12}O_{40}$과 Pt/AC+$Cs_{3.0}PW_{12}O_{40}$)와 비슷하였다. 이 반응을 진행하는 동안 Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ 촉매로부터 헤테로폴리 음이온이 침출되는 것을 확인하였다.

• 대한화학회지
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• 제36권5호
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• pp.685-691
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• 1992

디포스핀을 포함한 몇가지 $d^8$ 전이금속착물$(MCl_2PP)$은 출발물질 $K_nMCl_m$을 사용하여 합성하였다. 중심금속(M)은 Ni(II), Pd(II), Pt(II), Au(III)이며, 디포스핀(PP)은 bis(diphenylphosphino)methane(dppm), bis(diphenylphosphino)ethane(dppe), bis(diphenylphosphino)propane (dppp) 및 bis(diphenylphosphino)ethylene(dppety)이었다. 착물의 조성이나 특성은 원소분석과 $^1H-NMR$, $^{31}P-NMR$ 및 UV-Visible 스펙트럼을 이용하여 확인하였다. 이들 착물의 촉매적 활성은 3(2H)-furanone 및 cyclic carbonate 생성반응에 대하여 각각 조사하였다. 2-methyl-3-butyn-2-ol로부터 생성물 3(2H)-furanone을 얻은 반응 (1)에서 Ni(II)-, Pd(II)-diphosphine 착물은 좋은 촉매적 효과를 나타내었다. 그러나 이들 diphosphine 착물들은 cyclic carbonate 생성반응 (2)에 대해 촉매제로서의 활성을 거의 나타내지 않았다.

• Applied Microscopy
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• 제42권4호
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• pp.207-211
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• 2012

We examined the electrical properties and microstructure of NiO produced using a sol-gel method and Ni nitrate hexahydrate ($Ni[NO_3]_2{\cdot}6H_2O$) to investigate if this NiO thin film can be used as an insulator layer for resistance random access memory (ReRAM) devices. It was found that as-prepared NiO film was polycrystalline and presented as the nonstoichiometric compound $Ni_{1+x}O$ with Ni interstitials (oxygen vacancies). Resistances-witching behavior was observed in the range of 0~2 V, and the low-resistance state and high-resistance state were clearly distinguishable (${\sim}10^3$ orders). It was also demonstrated that NiO could be patterned directly by KrF eximer laser irradiation using a shadow mask. NiO thin film fabricated by the sol-gel method does not require any photoresist or vacuum processes, and therefore has potential for application as an insulating layer in low-cost ReRAM devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1419-1421
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• 1995

Nickel micro-structures are fabricated by electroless plating which shows better uniformity. Positive resist AZ4562 of 7 um thickness is patterned with minimum width of 2 um on poly-silicon as for sacrificial layer. The growth rate of Ni electroless plating is 10um/h both for the seed layer of Pt and TiW. TiW is found to be more practical than Pt, since it is very difficult to remove Pt with negligible damage to Ni structures.

• 한국표면공학회지
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• 제37권4호
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• pp.196-199
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• 2004

Seedlayers with low surface energy which increases the density of nucleation sites in the initial growth region of the recording layer deposited on them was studied to reduce grain size in recording layer. The seedlayer with low surface energy was so effective to attain finer grain in magnetic upper-layers. The Ni-Fe-O intermediate layer with low surface energy was found to be effective in reduction of grain size as well as magnetic cluster size of Co-Cr-Ta-Pt recording layer. Furthermore, the reduction of grain size in Co-Cr-Ta-Pt recording layer on Ni-Fe-O intermediate layer with low surface energy led to decrease the noise level in the high recording density region.

• 센서학회지
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• 제14권1호
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• pp.52-55
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• 2005

Ni oxide thin films with thermal sensitivity superior to Pt and Ni thin films were formed through annealing treatment after Ni thin films were deposited by a r.f. magnetron sputtering method. Resistivity values of Ni oxide thin films were in the range of $10.5{\mu}{\Omega}cm$ to $2.84{\times}10^{4}{\mu}{\Omega}cm$ according to the degree of Ni oxidation. Also temperature coefficient of resistance(TCR) values of Ni oxide thin films depended on the degree of Ni oxidation from 2,188 ppm/$^{\circ}C$ to 5,630 ppm/$^{\circ}C$ in the temperature range of $0{\sim}150^{\circ}C$. Because of the high linear TCR and resistivity characteristics, Ni oxide thin films exhibit much higher sensitivity to flow and temperature changes than pure Ni thin films and Pt thin films.

• 한국수소및신에너지학회논문집
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• 제19권5호
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• pp.423-429
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• 2008

This work was carried out to improve the performance of anodic electrocatalysts in direct ethanol fuel cell(DEFC). PtRu and $Pt_5Ru_4M$(M= Ni, Sn, Mo and W) electrocatalysts were prepared by using a $NaBH_4$ reduction method. Alloy crystal structure and particle size of electrocatalysts were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM). The XRD analysis of the electrocatalysts revealed that the face-centered cubic(fcc) peaks shifted to slightly higher diffraction angles when third metals were added. Average size of the uniform particles was observed to be approximately $3{\sim}3.5\;nm$ from the TEM image. The electrochemical measurements were carried out in the solution 1M $H_2SO_4$ and 1M $C_2H_5OH$ at room temperature. Cyclic-voltammogram results showed that $Pt_5Ru_4W$ electrocatalyst exhibited much higher current density for ethanol oxidation of $2.73\;mA/cm^2$ than PtRu electrocatalyst of $0.73\;mA/cm^2$.

• 센서학회지
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• 제6권3호
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• pp.221-227
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• 1997

Pd/NiCr 게이트 MISFET 센서는 변압기 절연유중 용존수소를 감지하기 위해 제조되었다. 센서의 안정성과 고농도 감지성의 향상을 위해 Pd/NiCr 2중 촉매 금속 게이트가 사용되었다. 수소유입에 의한 게이트 전압의 드리프트를 줄이기 위해, 2개의 FET 게이트 절연층을 실리콘 산화막과 실리콘 질화막의 2중 구조로 하였다. Pd/NiCr 게이트 MISFET 센서의 수소 감응 감도는 Pd/Pt 게이트 MISFET 센서의 감도에 비해 약 0.5배이나, 안정성이 좋고, 1000 ppm까지의 고농도까지 측정할 수 있었다.