• 한국산학기술학회논문지
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• 제10권10호
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• pp.2779-2785
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• 2009

육류 중에 닭은 가장 저렴한 생산비용으로 단백질을 섭취할 수 있는 장점으로 인하여 많은 양이 사육되며 우리나라 식생활의 육류 소비를 늘리는 중요한 가축이다. 생육조건에 악영향을 미치는 여러 요인 중에 축산업에서 가장 대표적인 것은 악취이다. 악취물질은 축분에서 발생되는 암모니아, 아민류, 황화수소 및 머캡탄을 들 수 있으며 악취는 없으나 악영향을 미치는 물질로는 메탄, 질소산화물 등이 있다. 이러한 악취물질에 의하여 가축은 생육에 저해를 받으며, 심한 경우 폐사까지 이르게 된다. 계사의 경우 겨울철에는 난방을 하고 있는 실정임에도 불구하고 나머지 계절과 같이 환기를 통하여 악취를 제어하고 있다. 겨울철의 경우 대부분의 계사가 등유를 사용하는 온풍기를 이용하여 난방을 하고 있으나 계사내의 유해한 암모니아의 농도가 높아지므로 인하여 환기를 시키고 있는 실정이다. 따라서 본 연구과제에서는 기존에 사용되고 있는 온풍기에 복합촉매시스템을 접합하여 계사 및 축사의 암모니아 등의 유해 가스를 제어할 수 있는 시스템에 사용될 촉매를 개발하였으며, Mn과 Pt-Rh을 최적의 조성으로 도출하였다.

• 청정기술
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• 제30권1호
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• pp.55-61
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• 2024

연료전지의 산소환원반응용 백금 촉매의 높은 비용을 극복하기 위하여 나노 구조 제어를 통한 고성능의 백금 합금 촉매 개발 연구가 활발히 수행되고 있다. 본 연구에서는 탄소에 담지된 니켈-니켈 질화물 복합체와 백금 이온 간의 갈바닉 치환 반응 시 용액의 pH 조절을 통한 촉매의 나노구조를 중공형이나 코어-쉘 구조로 제어하는 방법을 제시하였다. X선 회절 분석과 투과전자현미경, 유도결합 플라즈마를 이용한 분석을 통해 합성 조건에 따른 금속의 상태와 함량 및 합금 입자의 형상에 대한 물리적 특성 평가를 수행하였다. 제조된 촉매를 산소환원반응 촉매로 적용하였으며 상용 백금 촉매 대비 1.7배(중공형 촉매) 및 1.9배(코어-쉘 구조 촉매) 개선된 전기화학적 활성 면적 당 활성을 나타내었다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.266-269
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• 2004

In this study, bond strengths for the self-healing agents were evaluated through the modified lap shear test in order to suggest the optimal healing conditions for the repair of polymeric composites. The healing agents of DCPD, ENB, and their mixtures were activated with Grubbs' catalysts. According to the results, the mixture of DCPD and ENB gave better opportunity than DCPD only due to the rapid acivation with catalyst in view of the economic and practical use.

• 응용화학
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• 제15권2호
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• pp.137-140
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• 2011

Excellent active and stable platinum catalyst fuel cells currently being used as a catalyst. However, because of the high price of platinum catalyst, such as non-precious catalyst has been studied by a variety of fuel cell catalysts. In this study, Co/ PANi//CNT composite catalyst after synthesis through various heating process was to increase the activity of the catalyst. At 700℃ showed the best catalytic activity, using a composite catalyst was to be used as cathode electrodes in fuel cell.

• 청정기술
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• 제21권1호
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• pp.68-75
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• 2015

본 연구에서는 높은 열전도성을 갖는 금속-세라믹 core-shell 구조의 CoAl₂O₄@Al 복합체를 Al 금속의 수열반응을 통하여 합성하고, 이를 Rh 촉매의 담지체로 적용하여 구조적, 촉매화학적 특성을 분석하였다. Rh/CoAl₂O₄@Al (3 wt% Rh) 촉매는 단순침적법(incipient wetness impregnation)으로 제조하였고, 특성의 비교평가를 위하여 공침법(co-precipitation)으로 합성한 CoAl₂O₄를 담지체로 하여 Rh/CoAl₂O₄ (3 wt% Rh) 촉매를 단순침적법으로 제조하였다. 이들 촉매들은 N₂ 흡착, XRD, 전자 주사현미경, temperature programmed reduction (TPR), CO 화학흡착 분석을 통해서 그 특성을 분석하였고, 글리세롤 수증기 개질 반응(550 ℃)을 통한 수소전환반응에 적용하여 촉매적 특성을 평가하고 분석하였다. 글리세롤 수증기 개질반응에 대하여 Rh/CoAl₂O₄@Al 촉매는 Rh/CoAl₂O₄ 촉매에 비하여 약 2.8배 높은 글리세롤 전환 turnover frequency (TOF)를 보여주었고, 이는 높은 열전도성을 갖는 금속-세라믹 복합체를 통한 원활한 반응열의 전달에 기인한 것으로 분석되었다. CoAl₂O₄@Al 및 CoAl₂O₄ 담지체에서도 환원에 의하여 노출된 일부 Co 금속에 의한 촉매적 활성이 관찰되었는데, Rh/CoAl₂O₄@Al과 Rh/CoAl₂O₄ 촉매에서와 마찬가지로 core-shell 구조체인 CoAl₂O₄@Al이 CoAl₂O₄ 보다 높은 촉매적 활성을 보였다. 그러나, 이들 촉매는 글리세롤 개질반응에서 비교적 높은 비활성화를 보여주었고 이는 촉매표면의 탄소침적(coking)에 기인한 것으로 판명되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.33.1-33.1
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• 2009

To date, nanostructured tungsten oxides with a variety of stoichiometries, such as WO3, WO2.9, W18O49, and WO2, have been prepared, because they are promising candidates for applications such as gas sensors, photocatalysts, electrochromic devices, and field emission devices. Among them, W18O49 and WO2 have been widely studied due to their outstanding chemical sensing, catalytic, and electron emissive properties. Here we report, for the first time, a one-pot solution-phase route to synthesizing a novel composite hierarchical hollow structure without adding catalysts, surfactants, or templates. The products, consisting of a WO2 hollow core sphere surrounded by a W18O49 nanorod shell (yielding a sea urchin-like structure), were generated as discrete structures via Ostwald ripening. To our knowledge, this type of composite hierarchical core/shell structure has not been reported previously. The morphological evolution and the detailed growth mechanism were carefully studied. We also demonstrate that the size of the hollow urchins is readily tunable by controlling the reactant concentrations.Interestingly, although bulk tungsten oxides are weakly paramagnetic or diamagnetic, the as-prepared products show unusual ferromagnetic behavior atroom temperature. The urchin structures also show a very high Brunauer-Emmet-Teller (BET) surface area, suggesting that they may potentially be applied to chemical sensor or effective catalyst technologies.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1128-1134
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• 2010

Nanocarbon supported Fe/$TiO_2$ composite catalysts were prepared using CNTs (carbon nanotubes) and $C_{60}$ (fullerene) as nanocarbon sources by a modified sol-gel method. The Fe/$TiO_2$-nanocarbon composites were characterized by the BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and UV-vis spectra. In comparison with non-nanocarbon doped Fe/$TiO_2$ composites, the nanocarbon supported Fe/$TiO_2$ composites had higher absorption ability with a larger specific surface area, and showed higher photocatalytic activity during the degradation of methylene blue (MB) under visible light. The reasons for the obvious increase of photocatalytic activity indicated that the photoactivity not only benefits from nanocarbon introduced, but also relates to the cooperative effect of the Fe as a dopant.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.183-196
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• 2017

The research efforts directed at advancing water electrolysis technology continue to intensify together with the increasing interest in hydrogen as an alternative source of energy to fossil fuels. Among the various water electrolysis systems reported to date, systems employing a solid polymer electrolyte membrane are known to display both improved safety and efficiency as a result of enhanced separation of products: hydrogen and oxygen. Conducting water electrolysis in an alkaline medium lowers the system cost by allowing non-platinum group metals to be used as catalysts for the complex multi-electron transfer reactions involved in water electrolysis, namely the hydrogen and oxygen evolution reactions (HER and OER, respectively). We briefly review the anion exchange membranes (AEMs) and electrocatalysts developed and applied thus far in alkaline AEM water electrolysis (AEMWE) devices. Testing the developed components in AEMWE cells is a key step in maximizing the device performance since cell performance depends strongly on the structure of the electrodes containing the HER and OER catalysts and the polymer membrane under specific cell operating conditions. In this review, we discuss the properties of reported AEMs that have been used to fabricate membrane-electrode assemblies for AEMWE cells, including membranes based on polysulfone, poly(2,6-dimethyl-p-phylene) oxide, polybenzimidazole, and inorganic composite materials. The activities and stabilities of tertiary metal oxides, metal carbon composites, and ultra-low Pt-loading electrodes toward OER and HER in AEMWE cells are also described.

• Composites Research
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• 제17권5호
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• pp.47-53
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• 2004

본 연구에서는 열잠재성 양이온 촉매인 N-benzylpyrazinium hexafluoroantimonate (BPH)와 benryl-2,5-dimethylpyrazinium hexafluoroantimonate (BDPH)를 합성하였고, 이관능성 에폭시 수지(diglycidylether of bisphenol A, DGEBA)에 개시제로 1 wt.%의 촉매를 혼합하여 DSC, NIR TGA 그리고 DMA를 이용하여 경화거동과 열안정성을 알아보았다. 촉매의 잠재특성은 $100∼180^{\circ}$의 반응 온도에 따른 전환율을 near-IR로부터 조사하였다. NIR 분석으로부터, BPH에 의한 에폭시 수지의 전환율은 BDPH와 비교하여 높은 전환율을 나타내는 것을 확인할 수 있었다. 그리고 TGA 분석 결과, 초기 열분해 온도(IDT)와 적분 열분해 온도(IPDT)에 입각하여 DGEBA/BDPH 시스템의 열안정성이 DGEBA/BPH 시스템보다 상대적으로 낮은 값을 나타냈다. 이는 BDPH 구조의 입체 장애로 인해 BPH보다 열안정성 인자이 더 낮게 측정된 것으로 판단된다.

• Carbon letters
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• 제11권1호
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• pp.38-40
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• 2010

Carbon supported electrocatalysts are commonly used as electrode materials for polymer electrolyte membrane fuel cells(PEMFCs). These kinds of electrocatalysts provide large surface area and sufficient electrical conductivity. The support of typical PEM fuel cell catalysts has been a traditional conductive type of carbon black. However, even though the carbon particles conduct electrons, there is still significant portion of Pt that is isolated from the external circuit and the PEM, resulting in a low Pt utilization. Herein, new types of carbon materials to effectively utilize the Pt catalyst are being evaluated. Carbon nanofiber/activated carbon fiber (CNF/ACF) composite with multifunctional surfaces were prepared through catalytic growth of CNFs on ACFs. Nickel nitrate was used as a precursor of the catalyst to synthesize carbon nanofibers(CNFs). CNFs were synthesized by pyrolysising $CH_4$ using catalysts dispersed in acetone and ACF(activated carbon fiber). The as-prepared samples were characterized with transmission electron microscopy(TEM), scanning electron microscopy(SEM). In TEM image, carbon nanofibers were synthesized on the ACF to form a three-dimensional network. Pt/CNF/ACF was employed as a catalyst for PEMFC. As the ratio of prepared catalyst to commercial catalyst was changed from 0 to 50%, the performance of the mixture of 30 wt% of Pt/CNF/ACF and 70wt% of Pt/C commercial catalyst showed better perfromance than that of 100% commercial catalyst. The unique structure of CNF can supply the significant site for the stabilization of Pt particles. CNF/ACF is expected to be promising support to improve the performance in PEMFC.