• Korean Chemical Engineering Research
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• 제46권5호
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• pp.868-874
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• 2008

실리카, 알루미늄 실리케이트, 감마 알루미나 담체에 $Ni(NO_3)_2{\cdot}6H_2O$와 $Ni(CH_3COO)_2{\cdot}4H_2O$를 원료로 침전제인 요소와 시트르산을 사용하여 $90^{\circ}C$에서 공침법을 사용하여 흡착제를 제조하였으며 이를 환원시켜 일산화탄소 제거 실험을 수행하였다. 흡착제는 EDS, TPR, XRD 분석을 실시하여 이를 근거로 흡착제의 성능을 해석하였다. 침전제의 종류, 니켈 금속의 담지량, 담체, 니켈 금속의 염, 수소 환원 조건을 변화시켜 최적의 흡착 성능을 보이는 흡착제를 사용하여 실험을 수행하였다. 침전제인 요소에 $Ni(NO_3)_2{\cdot}6H_2O$를 사용하여 실리카 담체에 니켈 54.8 wt%를 담지하여 제조한 흡착제를 $500^{\circ}C$에서 3시간 수소 환원 전처리 후 흡착 실험을 하였을 때 가장 효과적으로 일산화탄소를 제거함을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.26-34
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• 2010

The electrocatalystic prperties of Pt-Co and Pt-Ni with heteropolyacids (HPAs) entrapped in covalently cross-linked sulfonated poly(ether ether ketone) (CL-SPEEK)/HPA membranes were investigated for water electrolysis. The HP As, including molybdophosphoric acid (MoPA), and tungstophosphoric acid (TPA) were both used as membrane additives and electrocatalysts. The membrane electrode assembly (MEA) was prepared by a nonequilibrium impregnation-reduction (I-R) method. $Pt(NH_3)_4Cl_2$, $NiCl_2$ and $CoCl_2$ as electrocatalytic materials and $NaBH_4$ as reducing agent were used. I order to enhance electrocatalytic activity, the catalyst layer prepared above was electrodeposited (Dep) with HP A. Surface morphologies and physico-chemical properties of MEA were investigated by means of SEM, EDX and XRD. The electrocatalytic properties of composite membranes such as the cell voltage and coulombic charge in CV were in the order of magnitude: CL-SPEEK/MoPA40 (wt%) > CL-SPEEK/TPA30 > Nafion117. In the optimum cell applications for water electrolysis, the cell voltage of Pt/CL-SPEEK-MoPA40/Pt-Co (Dep-MoPA) and Pt/CL-SPEEK-TPA30/Pt-Co (Dep-TPA) was 1.75 Vat $80^{\circ}C$ and $1\;A/cm^2$ and voltage efficiency was 87.1%. Also, the observed activity of Pt-Co (84:16 atomic ratio by EDX) is a little higher than that of Pt-Ni (86: 14). The current density peak of electrodeposited electrodes were better a little than those of unactivated electrodes based on the same membranes.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권4호
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• pp.1-7
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• 2015

The degradation of off-flavors which is 2-Methylisoborneol (2-MIB) and geosmin by means of ultrasound (US) and pulsed ultraviolet (PUV) irradiation and its combination with catalyst (wire mesh, wire mesh coated TiO₂, and TiO₂) and additive (H₂O₂) were investigated via water system. A combination treatment of TiO₂ and H₂O₂ heterogeneity with US (24 kHz) and PUV (6000 W) has shown improved results in destroying 2-MIB and geosmin, which may be attributed to chain reactions by the enhanced formation of hydroxyl radicals (·OH) through H₂O₂ dissociation and reactive oxide ions of TiO₂ addition. Rapid degradation of off-flavors occurred within 2 min under PUV process with H₂O₂ 100 mg/L (81.5% for 2- MIB; 79.3% for geosmin) and TiO₂ 100 mg/L (83.7% for 2-MIB; 79.8% for geosmin), while compared with H2O2 100 mg/L (58.4% for 2-MIB; 58.0% for geosmin) and TiO₂ 100 mg/L (59.2% for 2-MIB; 38.5% for geosmin) within 5 min under US process. Surprisingly, the emphasis was given on the comparison with the same injected energies between PUV and US on degradation efficiency. Based on the injected energy comparison, the US provided better degradation performance under equal input power of 200 kJ with H₂O₂ 100 mg/L, while compared with H₂O₂ 100 mg/L under PUV process. Our findings suggest that US can be more effective compared to PUV for the degradation of off-flavors in aspect of energy consumptions.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.362-367
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• 2023

최근 고분자 전해질 연료전지(PEMFC)에서 고분자 막의 연구개발은 가격 저감과 성능 향상을 위해 박막화하는 방향으로 진행되고 있다. 그리고 상용차용 수소 전기 차량 수요가 증가하고 있는데, 승용차용보다 내구성이 5배 증가해야 한다. 막의 두께가 얇아짐에도 불구하고 내구성은 5배 증가해야 하므로, 막의 내구성 향상이 더 중요해진 상황이다. 가속 내구 평가 시간도 단축해야하기 때문에 기존 프로토콜에서 공기 대신 산소를 사용한 프로토콜을 10 ㎛ 박막에 적용해 내구성을 평가하였다. 가속 내구 평가(개회로 전압 유지)는 720시간에 종료하였다. 공기를 사용한 미국 에너지부(DOE) 프로토콜을 사용했다면 약 1,500시간의 내구성으로 운전시간 450,000 km 수명을 예상한다. 화학적 내구 평가중에 전극의 활성 면적이 51% 감소해 촉매 열화가 막 내구성 약화에 영향을 준 것으로 판단되고, 촉매 열화 속도를 감소시키면 막 내구성이 증가할 것으로 예상된다.

• Journal of Information Display
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• 제2권3호
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• pp.78-85
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• 2001

The growth of carbon nanotubes(CNTs) in anodic aluminum oxide(AAO) template and their application to a field emitter are described. AAO templates were fabricated by anodizing bulk aluminum and sputtered thin Al film on Nb-coated Si wafers. After Co catalyst had been electrochemically deposited into the bottom of the pores in AAO template, CNTs were grown by pyrolyzing $C_2H_2$. Depending on the reaction conditions, CNTs grew up to or over the top of the pores in AAO template with different structures. The morphology and structure of CNTs were observed with a scanning electron microscope and a transmission electron microscope. The diameter of CNTs strongly depended on the size of the pores in AAO template and the growing conditions. The electron field emission measurement of the samples resulted in the turn-on field of 1.9-2.2 $V/{\mu}m$ and the field enhancement factor of 2450-5200. The observation of high field enhancement factors is explained in terms of low field screening effect.

• 대한화학회지
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• 제54권1호
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• pp.23-26
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• 2010

Schiff 리간드인 (Z)-N-((Z)-2-(sec-butylimino)-1,2-diphenylethylidene)butan-2-amine을 벤질과 sec-부틸아민과의 축합반응에 의해 합성하였다. 일 주기 전이금속인 망간(II) 및 니켈(II)과 리간드와의 착물반응을 시도하였다. 리간드 및 착물의 특성을 FTIR, 원소분석 및 열무게분석으로 고체 상태에서, 그리고 NMR ($^1H,\;^{13}C$)로 용액 상태에서의 각각 조사하였다. 두 착물 모두 온화한 조건에서 methylaluminoxane (MAO) 존재 하에 부타디엔 올리고화 반응의 조촉매로 좋은 촉매활성을 보였다.

• 전기화학회지
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• 제13권4호
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• pp.240-245
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• 2010

This work explored the catalytic effect of Pt in multi-wall carbon nanotube and poly-pyrrole conductive polymer electrocatalysts (Pt/PPy/MWCNT). A home-made Pt/PPy/MWCNT catalyst was first evaluated by comparing its electrochemical active surface area (ESA) with E-Tek commercial catalysts by cyclic voltammetry in $H_2SO_4$ solution. Then, the methanol oxidation currents of Pt/PPy/MWCNT and the hydrogen peaks in $H_2SO_4$ solution were serially measured with microporous electrode. This provided the current density of methanol oxidation based on the ESA, allowing a quantitative comparison of catalytic activity. The current densities were also measured for Pt/C catalysts of E-Tek and Tanaka Precious Metal Co. The current densities for the different catalysts were similar, implying that catalytic activity depended directly on the ESA rather than charge transfer or electronic conductivity.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3177-3183
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• 2012

The carbon nanofibers (CNFs) used in this study were synthesized with an iron catalyst and ethylene as a carbon source. A concentration of 30 wt % iron(III) acetylacetonate was dissolved in resol type phenol resin and polyurethane foam was put into the solution. The sample was calendered after being cured at $80^{\circ}C$ in air for 24 h. Stabilization and carbonization of the resol type phenol resin and reduction of the $Fe^{3+}$ were completed in a high-temperature furnace by the following steps: 1) heating to $600^{\circ}C$ at a rate of $10^{\circ}C/min$ with a mixture of $H_2/N_2$ for 4 h to reduce the $Fe^{3+}$ to Fe; 2) heating to $1000^{\circ}C$ in $N_2$ at a rate $10^{\circ}C/min$ for 30 minutes for pyrolysis; 3) synthesizing CNFs in a mixture of 20.1% ethylene and $H_2/N_2$ at $700^{\circ}C$ for 2 h using a CVD process. Finally, the structural characterization of the CNFs was performed by scanning electron microscopy and a synthesis analysis was carried out using energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Specific surface area analysis of the CNFs was also performed by $N_2$-sorption.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.561-564
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• 2006

Fe, Co, Zn, Cu, Pt 등의 전이금속과 ZSM-5 2종($SiO_2/Al_2O_3$ 몰비: 23, 50)과 ${\gamma}-alumina$를 담체로 사용하여 촉매를 합성하였다. 합성방법은 CVD(화학기상증착법) 과 Dry Impregnation (건식함침법)방법이었다. CVD 방법으로 얻은 Fe/ZSM-5는 지지체로 사용된 ZSM-5의 $SiO_2/Al_2O_3$의 몰 비가 작을수록, 즉 산점의 수가 많을수록 Fe 담지 량이 증가하는 것으로 보인다. 등온 환원 온도 $400^{\circ}C$에서 수소 환원 양이 최대로 나타나며, 이는 보고되는 $400^{\circ}C$에서의 최대 NOx 제거 반응 속도와 비례하는 것으로 나타난다.

• 한국재료학회지
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• 제11권9호
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• pp.727-732
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• 2001

The cure kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4'- methylene dianiline (MDA) system with synthesized phenyl glycidyl ether-dimethylurea (PGE-DMU) was studied by Kissinger and Ozawa equations with DSC analysis in the temperature range of $20~300^{\circ}C$ To investigate the reaction mechanism between epoxy group of PGE and urea group of DMU, FT-lR spectroscopy analysis was used. The epoxide group of PGE reacted with the urea group of DMU and formed a hydroxyl group which acted as a catalyst on the cure reaction of other epoxide and amine groups. The activation energy of DGEBA/MDA system without PGE-DMU was 46.5 kJ/mol and those of the system with 5 and 10 phr of PGE- DMU were 43.4 and 37.0 kJ/mol, respectively. Ozawa method also showed the same tendency.