• Korean Chemical Engineering Research
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• 제50권4호
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• pp.627-631
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• 2012

휴대용 고분자전해질 연료전지의 수소발생용으로써 $NaBH_4$는 많은 장점을 갖고 있다. 본 연구에서는 $NaBH_4$ 가수분해 반응용 Co-P-B/Cu 촉매의 내구성에 대해 연구하였다. Co-P-B/Cu 촉매의 내구성 미치는 반응 온도, $NaBH_4$ 농도, NaOH 농도, 촉매 소성온도 등의 영향에 대해 실험하였다. 촉매의 내구성은 가수분해 반응 중에 발생하는 gel 형성에 영향을 받았다. 즉 gel 형성에 의해 촉매 손실률이 증가하였다. $NaBH_4$ 농도가 고농도일 때는 $60^{\circ}C$ 이상에서는 gel 형성이 안 되어 촉매 손실률이 낮았다. 그러나 $40^{\circ}C$ 이하에서는 gel이 형성되어 촉매 손실률이 증가했다. $NaBH_4$ 20 wt%, $40^{\circ}C$에서 NaOH 농도증가에 따라 겔이 형성되어 촉매 손실률이 증가함을 보였다. Co-P-B/Cu 촉매의 높은 온도에서 소성은 내구성을 향상시켰지만 촉매 활성을 감소시켰다.

• 전기화학회지
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• 제6권1호
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• pp.65-67
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• 2003

The present paper highlights on the need to understand the correlation of the characteristics of the catalyst layer with the performance of the polymer electrolyte membrane fuel cell (PEMFC). This paper deals with the correlation of the platinum loading in the catalyst layer and the performance of the polymer electrolyte membrane fuel cell and also the correlation of the required hydrophilicity/hydrophobicity in the catalyst layer to get the optimum performance under given operating conditions.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.69-78
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• 2018

A study has been carried out of the regenerability of a commercial Ni catalyst used in the steam reforming of the volatiles from biomass pyrolysis (gases and bio-oil), determining the evolution of the reaction indices (conversion, product yields and $H_2$ production) in successive reaction-regeneration cycles. The causes of catalyst deactivation (coke deposition and Ni sintering) have been ascertained characterizing the deactivated and regenerated catalysts by TPO, TEM, TPR and XRD. Catalyst activity is not fully recovered by coke combustion in the first cycles due to the irreversible deactivation by Ni sintering, but the catalyst reaches a pseudo-stable state beyond the fourth cycle, reproducing its behaviour in subsequent cycles.

• 반도체디스플레이기술학회지
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• 제3권1호
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• pp.9-13
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• 2004

Carbon nanofibers (CNFs) with uniform diameter and controlled size were prepared from catalytic decomposition of $\textrm{C}_{2}\textrm{H}_{2}$ with Ni-MgO catalyst treated by mechanochemical (MC) process. The properties of Ni catalyst, such as size, distribution and morphology, can be governed by tuning grinding time in MC process. As a result, size and structure of CNFs can be tailored. The effect of grinding time to the as-grown CNFs was studied. CNFs with diameter from 10-70 nm were synthesized. CNFs with bundle formation sharing one tip and twisted CNFs were also synthesized with catalyst treated by MC process.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.341-347
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• 2023

PEMFC(Proton Exchange Membrane Fuel Cells)에서 PtCo/C 합금 촉매가 성능이나 내구성에서 우수하여 많이 사용되고 있다. 그러나 높은 전압에서(1.0~1.5 V) 평가되는 촉매 지지체 내구성에 관한 연구는 별로 보고 되지 않았다. 본 연구에서는 PtCo/C 촉매와 Pt/C 촉매에 촉매 지지체 가속 열화 프로토콜을 적용한 후 내구성을 비교하였다. 1.0↔1.5V 전압 변화 사이클 반복 후에 촉매 비활성도(Mass activity)와 전기화학적 활성면적(ECSA), 전기이중층 용량(DLC), Pt 용해와 입자 성장 등을 분석하였다. 전압변화 2,000 사이클 후 PtCo/C 촉매는 Pt/C 촉매에 비해 0.9 V에서 촉매 무게당 전류밀도가 1.5배 이상 감소하였다. 이와 같은 결과는 PtCo/C 촉매의 카본지지체의 열화 속도가 Pt/C 촉매보다 높기 때문이었다. Pt/C 촉매는 PtCo/C 촉매보다 촉매층의 ECSA 감소가 1.5배 이상 높았지만 Pt/C 촉매의 카본 지지체 부식이 작아 I-V 성능 감소가 작았다. PtCo/C 촉매의 고전압 내구성 향상을 위해서는 카본 지지체 내구성 향상이 필수적임을 보였다.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1785-1789
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• 2002

2,2'-Dichlorohydroazobenzene was prepared by selective hydrogenation of o-nitrochlorobenzene with hydrogen in the presence of 0.8% and 5% Pd/C catalyst. O-Chloroaniline was a minor product in the catalytic hydrogenation of o-nitrochlorobenzene. The effects of base, Pd/C catalyst, and co-catalyst were discussed on catalytic hydrogenation. 2,2'-Dichlorohydroazobenzene, as an intermediate, was rearranged to 3,3'-dichlorobenzidine after reacting with HCl. It was shown that selectivity of catalytic hydrogenation of o-nitro-chlorobenzene is affected strongly by concentration of base, Pd/C catalyst, and co-catalyst. $^1Hand^{13}C$NMR spectroscopy confirmed the chemical structures of 2,2'-dichlorohydrazobenzene and 3,3'-dichlorobenzidine.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.364-371
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• 2018

Enzyme polymerization is a benign process exploiting the unique activity of enzymes. In this study, a peroxidase-mimetic catalyst is demonstrated as an alternative to horseradish peroxidase (HRP) for the polymerization of aniline. The mimetic catalyst successfully catalyzes the polymerization of aniline monomers to produce polyaniline (PANI) in an aqueous solution. The PANI produced is rich of para-structure that is generally observed when HRP is used as a catalyst. Compared to HRP, the peroxidase-mimetic catalyst shows a considerably higher catalytic activity at neutral and weak basic conditions (pH >6.5) and at temperatures over $45^{\circ}C$, at which HRP is denatured.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.137-141
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• 2004

Many monopropellant thrusters use a catalyst for decompose the propellant, hydrazine. The catalyst directly affects the thruster performances and lifetime. Therefore, it is important to confirm that the catalyst is suitable for our thrusters. Until 2002, we used She1l405 catalyst, for satellite RCS thrusters, and H-IIA and M-V launch vehicle upper-stage RCS thrusters. In 2002, however, Shell Chemical Inc. ceased manufacturing She1l405 catalyst and transferred the product to AEROJET, where it was renamed S405. We subsequently investigated the characteristics of AEROJET's S405 catalyst and SOLVAY's KC12GA catalyst, (SOLVAY is a Belgian chemical company, and KC12GA is used for ASTRIUM's thruster) and conducted thruster firing tests using the new catalysts. After conducting, we confirm that the KC12GA catalyst was suitable for our thrusters, and decided to use KC12GA for two satellite programs.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1280-1282
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• 2010

A new chiral catalyst was synthesized and found that it could catalyzed the asymmetric Michael reaction of ketones with nitroolefins smoothly at room temperature, giving the desired adducts in 71 - 92% yields with excellent diastereoselectivities and high enantioselectivities (up to 95% ee).

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2963-2967
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• 2013

This paper describes a simple and efficient method involving domino Knovenegal/$6{\pi}$ electrocyclization for the preparation of a variety of 2H-pyrans using microwave irradiation under solvent- and catalyst-free conditions. This method offers the advantages of a green approach, high yields, and short reaction times. Sixteen compounds (9a-p) were obtained in good to excellent yields using the procedure.