이중구조 촉매전극을 이용한 알칼리 연료전지에 관한 연구

노용우,이태희,설용건,장의종,김경림 연세대학교 산업기술연구소 1990 논문집 Vol.22 No.1

An experimental low-temperature low-pressure hydrogen-oxygen alkali fuel cell was constructed and its performance was tested for various operating conditions. Hydrogen was used for fuel and oxygen was used for oxidant and KOH solution was used for electrolyte. Both electrodes for hydrogen and oxygen were prepared by the same method and the materials used were carbonyl nickel and ammonium bicarbonate. Experimental results show that maximum current density of 8.91 mA/㎠ was obtained at 40℃ wt% KOH solution and optimum power was 1.74 mW/㎠ at 6.43 mA/㎠ current density.

폴리카보네이트 멤브레인 표면의 불소화 개질에 의한 물 투과도 변화

민광준,설용건,전명석,김홍곤 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.6

균일한 기공을 가진 polycarbonate track etched membrane의 불소화로 인한 표면특성과 물 투과도의 변화를 조사하였다. 반응온도와 반응시간을 각각 상온과 3분으로 일정하게 유지하면서 질소로 희석된 혼합가스의 불소 농도 및 압력을 변화시켜 멤브레인을 불소화하였다. Field emission scanning electron microscopy(FESEM)을 통해 혼합가스의 절대압력이 1.5 bar 이하이고 불소, 질소 혼합비가 1:30으로 희석되었을 때 멤브레인 표면이 손상되지 않음을 알 수 있었다. 또한, 혼합비 1:30의 혼합가스로 1.5 bar에서 불소화한 멤브레인의 물 투과도는 원래 멤브레인의 2배 가까이 증가하였다. 불소화 압력이 낮으면 표면은 친수성을 띈 반면, 불소화 압력이 증가하면 소수성으로 변하였다. X-ray photoelectron spectroscopy(XPS)를 통해 불소 분압이 높아짐에 따라 멤브레인 표면에서 내부로의 불소 침투속도가 증가하는 현상과 불소가 도입된 부분의 산소 함량이 증가한 현상을 볼 수 있었다. 표면이 소수성을 띄는 멤브레인의 물 투과도가 증가한 현상은 기공 표면이 소수성을 띌수록 slip 경계조건에 근접하게 되어 기공을 통한 물 흐름이 원활해졌기 때문으로 해석되었다. The effect of fluorination on the surface characteristics and water permeability of an isopore polycarbonate track etchet membrane was examined. The membrane was fluorinated with gas mixtures containing fluorine and nitrogen of various composition under various pressure at room temperature for 3 minutes. The field emission scanning electron microscopy(FESEM) analysis showed that the shape of the membrane surface was not changed when it was fluorinated with a gas mixture at 1.5 bar which contained a low molar ratio of fluorine to nitrogen such as 1:30. Meanwhile, the membrane fluorinated with a mixture having a F₂:N₂ ratio of 1:30 at 1.5 bar showed an improved water permeability almost twice higher than that the original membrane had. The membrane surface got to possess more hydrophilicity than the original one when it was mildly fluorinated at low pressure. However, it became hydrophobic when it was further fluorinated under higher pressure. X-ray photoelectronospectroscopy(XPS) analysis revealed that the penetration rate of fluorine into the membrane increased along with the increase of the partial pressure of fluorine and that the inner layer containing fluorine possessed more oxygen than that in the original membrane. The phenomenon that the membrane having hydrophobic surface showed high water permeability was due to the slip boundary condition in the pore surface where water droplets pass through hydrophobic pores more easily with less friction resistance than through hydrophilic pores.

PECVD로 증착한 TiN 박막의 속도론적 고찰

안경한,설용건 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.2

Kinetic models of TiN deposition from TiCl₄, N₂, H₂ gas in PECVD reactor were developed and evaluated with experimental results by reference. The model postulated several dissociation steps of the TiCl₄ as follows; TiCl₄ →TiCl₃ and TiCl₂, (1), TiCl₄→TiCl ₃ (2), TiCl₄ →TiCl₂ (3), Those deposition reactions were established by Riedel-Eiley mechanism. The model equations were solved by non-linear regression analysis in IMSL Math Library. Estimated results based on (1) and (2) were fitted well. The effect of H₂ and N₂ on TiN formation was also successfully explained.

연료전지 전극의 기공구조와 산흡수도

김성엽,설용건,이태희,노용우 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.2

Pore structure and acid absorbancy of carbon electrode of phosphoric acid fuel cell were studied by varying carbon black, PTFE loading, and fabricating method for Denka black. Results showed that the primary pore(micro pore) of the carbon electrode included the micro space formed around the carbon particles regardless of the carbon black(Vulcan XC-72 and Denka black) used, and that addition of PTFE and pressing of electrode influenced mainly the secondary proe. The acid absorbancy of electrode was decreased as PTFE loading was increased and Denka black showed more hydrophobic than Vulcan XC-72 with three times in saturation time and one-half in acid absorbancy.

티탄산칼륨 분말 및 섬유합성

정경택,설용건 연세대학교 산업기술연구소 1994 논문집 Vol.26 No.2

Synthesis of potassium titanate powders and fibers have been studied according to various synthetic method-melting method, rapid cooling method and flux method. Potassium hexa titanate was synthesiezed over the temperature range 950-1050℃, within 10hrs. Potassium tetra titanate was synthesiezed at 900℃ for 72hrs, by melting method. In rapid cooling method, potassium hexa titanate was grown with the dimension of 0.01mm(diameter) X 1mm(length). The potassium hexa titanate fibers with the maximum size of 0.05mm(diameter) X 4mm(length) was grown in case of flux method. Recooling method and seed method by using potassium hexa titanate as seed produced more and longer size of fibers than the case of slow cooling method.

연료전지의 인산전해질 함유를 위한 Marix 제조에 관한 연구

이승훈,설용건,이태희 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.2

The matrix used for the electrolyte of fuel cell was fabricated by using the powder of having different particle size SiC(Silicon Carbide). About the above fabricated matrix, the pore structure and acid absorbancy were measured, and the performance was finally tested at On-Cell. In making matrix, teflon was used as its binder, and in the case of adding 10w/o, matrix could be made in the form of the sheet of 0.2~0.3mm in width. As the result of having made matrix, in the case of 1μm of it, its porosity of 61% was highest; the smaller the size of its particle was, the more increasing pore volume became; the more increasing the content of teflon got, the more decreasing pore volume became. The acid absorbancy of matrix became saturated with acid after six hours, and in the case of 1 μm matrix its acid absorbancy was highest. The highest performance of the matrix with 1μm particle resulted from the measurement of the performance of the On-Cell also the current density of 75mA/cm2at 700mV.

Cu-SiO₂촉매상에서 메탄올의 메틸포메이트로의 탈수소 반응에 관한 연구

김경림,박해경,설용건,이태희,전민기 연세대학교 산업기술연구소 1990 논문집 Vol.22 No.2

Cu-SiO₂촉매상에서 구리의 함량을 달리하며 메탄올을 반응물질로 하여 탈수소 반응을 고정층 연속흐름 반응기에서 행하였다. 조작조건의 범위는 온도 175∼250℃, 압력 ?? 접촉시간 0.013∼0.043g.cat.hr/mL이었다. 구리의 함량에 따라 전화율과 선택도가 달라지고 구리의 함량이 1.5wt.%일 때 메틸포메이트로의 수율이 가장 좋았다. 최적 조작 조건은 온도와 접촉시간이 각각 225℃, 0.033g.cat.hr/mL 부근이었다. 이온 교환법으로 제조된 1.5wt.% Cu-SiO₂촉매상에서 메탄올의 탈수소 반응의 활성화 에너지는 3.73kcal/mol이었다. The dehydrogenation of methanol to methylformate was studied over Cu-SiO₂catalyst prepared by ion-exchange method with the change of copper content in a fixed bed, continuous flow reactor. The ranges of experimental conditions were : at the temperature between 175℃ and 250℃, pressure at ??, and contact time between 0.013 and 0.043g.cat.hr/mL. Conversion and selectivity were changed with Cu content and yield of methylformate showed the highest value with 1.5wt.% Cu. The optimum conditions were 225℃, 0.033g.cat.hr/mL for reaction temperature and contact time, respectively. The activation energy of dehydrogenation of methanol to methylformate was 3.73kcal/mol over 1.5wt.% Cu-SiO₂.

Photocatalytic Decomposition of NO on Transition Metal Ion-exchanged Zeolite Catalysts

Shul, Yong Gun,Park, Sang Eon,Yamashita, Hiromi,Anpo, Masakazu,Matsuoka, Masaya,Ju, Woo Sung 한국공업화학회 2000 Journal of Industrial and Engineering Chemistry Vol.6 No.3

Transition metal ions (Cu^+, Ag^+) incorporated within the cavities of zeolites by an ion-exchange method show an efficient and unique photocatalytic performance for the decomposition of NO into N₂ and O₂ at 275 K. In situ ESR, UV-VIS, photoluminescence and XAFS (XANES and FT-EXAFS) investigations revealed that the transition metal ions exist in highly dispersed state with linear 2 coordination sphere within the pores of zeolites, the local structures of the metal ions being significantly affected by changing the kinds of zeolites. Detailed studies of the interaction of NO with the excited states of these metal ions clearly indicated that unique inner shell type excitation states of these metal ions play a significant role in the photocatalytic decomposition of NO, i.e., an electron transfer from the s orbital of the excited state of Cu^+ or Ag^+ ions into the π^* antibonding orbital of NO initiates the decomposition reaction of NO.

The particle size effect of N-doped mesoporous carbons as oxygen reduction reaction catalysts for PEMFC

Yong-Gun Shul,Ulziidelger Byambasuren,Yu Kwon Jeon,Dorjgotov Altansukh,Yunseong Ji 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.6

The particle size effect of N-doped mesoporous carbon was investigated for ORR activity in acid condition and for issue of a mass transfer and gas diffusion in PEMFCs. As for a non-Pt ORR catalyst, nitrogen (N)-doped ordered mesoporous carbons (OMCs) with a various particle sizes with the range of the average 20, 45 and 75 μm were synthesized by the precursor of polyaniline for the N/C species, and a mesoporous silica template was used for the physical structure for preparation of nitrogen doped OMCs. The N-doped mesoporous carbons are promoted by a transition metal (Fe) to improve catalytic activity for ORR in PEMFCs. All the prepared carbons were characterized by via scanning electron microscopy (SEM), and to evaluate the activities of synthesized doped carbons, linear sweep was recorded in an acidic solution to compare the ORR catalytic activities values for the use in the PEMFC system. The surface area and pore volume were increased as the particles decreased, which was effective for the mass transfer of the reactant for higher activity at the limiting current regions.

Synthesis of Organic - Inorganic Composite Membrane by Sol - Gel Process

Shul, Yong Gun,Chun, Kyoung Yong,Kim, Han Sung,Joe, Yung Il,Han, Jung Woo 한국화학공학회 1995 NICE Vol.13 No.6

Silica was succesfully incorpm-ated into canon exchange polymer membranes, CL-25 and Nation 417, utilizing sol-gel process. As dipping time increased, increase in silica uptake in membrane was observed. In Nation 417 membrane, no relationship was found between the silica uptake and the change in ion exchange capacity. But CL-25T which has larger pores than Nation 417 shows proportional decrease in ion exchautge capacity with increasing silica uptake. It suggests that the pore structure of membrane and the size control of silica sol are important to modify- the structure of composite membranes. In CL-25T membranes modified by silica, the transport rate of IPA (isopropyl alcohol) increased with increasing OH concentration on the pore surface.