초록 ▼

탄소재료는 결합상태에 따라 카본 블랙, 활성탄, 탄소섬유, 탄소나노튜브 등으로 형태가 다양하며 탄소 재료가 화학적으로 매우 안정하고, 열 및 전기전도성이 우수하며, 기계적인 특성 면에서도 고강도, 고탄성율을 가지고 있어서 구조적으로 안정하기 때문에 그 응용 또한 광범이하게 활용이 시도되고 있다. 본 연구에서는 다양한 탄소재료의 전구체를 이용하여 수소저장, 수소 생성 및 응용기술에 활용하기 위한 연구를 진행하였다. 고성능 탄소소재 제조를 위하여 탄소박막을 제조한뒤 금속이 담지 된 산화아연이 전기 증착하여 수소생산 소재로서의 가능성을

탄소재료는 결합상태에 따라 카본 블랙, 활성탄, 탄소섬유, 탄소나노튜브 등으로 형태가 다양하며 탄소 재료가 화학적으로 매우 안정하고, 열 및 전기전도성이 우수하며, 기계적인 특성 면에서도 고강도, 고탄성율을 가지고 있어서 구조적으로 안정하기 때문에 그 응용 또한 광범이하게 활용이 시도되고 있다. 본 연구에서는 다양한 탄소재료의 전구체를 이용하여 수소저장, 수소 생성 및 응용기술에 활용하기 위한 연구를 진행하였다. 고성능 탄소소재 제조를 위하여 탄소박막을 제조한뒤 금속이 담지 된 산화아연이 전기 증착하여 수소생산 소재로서의 가능성을 살펴보았고, 단분산성 PMMA 비드를 합성한 후 탄화하여 탄소볼을 제조하여 수소저장 재료로서의 가능성을 살펴보았다. 또한 볏짚을 이용하여 활성탄소필름 및 탄소 섬유를 제조하고 수소 저장능을 향상시키기 위해 팔라듐과 금속을 담지시켰다. 본 2차년도 연구결과를 요약하면 하기와 같다.
고성능 탄소 소재 제조 기술 개발
- 탄소 구조체 함성 기술 개발
* 볏짚 및 닥나무 등 바이오매스를 이용하여 탄소 섬유 및 필름 제조
* 고분자를 이용하여 탄소박막 및 탄소볼 제저
* 전기방사를 이용하여 탄소 섬유 제조
- 표면 개질을 통해 표면 특성 향상
* 금속 담지를 통해 수소생산 및 수소저장능 향상
* 표면 개질을 이용하여 비표면적 및 기공 향상
- 수소저장 소재 기술 개발
* 수소 생산 평가 기술 확립
* 수소 저장능 평가 기술 확립
* 7 wt.% 이상의 수소 저장능 확보 : 현재 4.359 wt.% 수소 저장능 확보

( 출처 : 보고서 초록 3p )

Abstract ▼

Carbon materials are of very high technological importance because of their mechanical, electronic, as well as molecular sorption and sieving properties. A large variety of brands and grades of carbon determines an accordingly wide range of practical applications in heterogeneous catalysis as a cata

Carbon materials are of very high technological importance because of their mechanical, electronic, as well as molecular sorption and sieving properties. A large variety of brands and grades of carbon determines an accordingly wide range of practical applications in heterogeneous catalysis as a catalyst support material in hydrogenation processes, in fuel cell electrodes as gas diffusion and catalyst material, in gas separation and purification of gases and liquids. An important step in the design of a material for a particular application, especially in catalysis and sorption, is the control of the surface morphology, i.e. the right balance between the amounts of the free surface, micro and mesoporosity. With respect to its potential use as an energy carrier, hydrogen, on the other hand, seems to have become a key and very fashionable element in nowadays scientific, but also industrial and political life. Indeed, a brief check with any chemistry handbook shows that burning 1 mol of H₂ delivers about 230 kJ/mol of heat, i.e. energy, and produces water vapour as the only by-product. This means that 1 kg of H₂ delivers 32 kW h of energy compared to about 12 kW h/kg for petrol (and practically the same for Diesel). Hence, with its possibly environmentally friendly and closed regenerative cycle, hydrogen turns out to be an ideal energy carrier which is believed to replace petrol when the later becomes an extinct, or even earlier. The high efficiency of hydrogen as a fuel is due to the fact that it is very light which, on the other hand, is the major obstacle for its efficient storage.

Thus, the volumetric energy density of liquid hydrogen is more than three times lower than that of petrol. Finding a way of forming dense condensed phases, as dense as the bulk solid at least, but operating at much higher temperatures, well above 14 K– the triple point of bulk hydrogen, is a task of crucial importance. For a mobile storage application to be competitive to a conventional petrol tank, a target hydrogen storage density of 6.5% by weight, operating at ambient conditions, has been set. This target has not yet been met by any of the current storage technologies being: (a) compressed gas, (b) liquid hydrogen, and (c) metal hydrides. An alternative to these is the storage of hydrogen in a porous solid via a physical adsorption process. Some very optimistic results regarding this storage mechanism have been reported during the past two decades. The discovery of Multi- and Single-Wall carbon Nanotubes, (MWNT and SWNT) and Graphite Nanofibers (GNF) ignited recent intensive activities on H₂ storage.

Thus, SWNT appeared capable of storing a few percent by weight of hydrogen at room temperatures and 1bar pressure. Soon after, these were outshined by the results of H2 storage tests of GNF where some 70 wt% were measured. In return, the storage performance of SWNT was dramatically improved by doping the material with alkali metals. It was then suggested that the presence of impurities such as water in the H₂ gas supply and respectively in the adsorbate (mainly H₂O) may have too big share in the storage values previously reported. At 80 K and pressures of up to 100 bar, densities corresponding to about 7 % were reached. More recent studies have shown, however, that at 77 K and 1 bar pressure the H2 capacity is about 1 wt%. To achieve the same concentration at room temperatures, one would need pressures of the order of 102 bar. In special, activated carbons of various morphologies have also been in the focus of the scientific research. Thus, one and the same type of material, potassium hydroxide activated carbon, has been once shown to adsorb about 6 wt% at 77 K and 50 bar pressure. However, that H2 adsorption in carbons at high pressures is not efficient because of the large portion of excluded volume.

It is now generally recognized that the storage capacity is about linearly proportional to the specific surface area of the material and the proportion of microporosity, which enhances the adsorption at low pressures.
Experiment and theoretical calculations show that the optimal geometry for physisorption is the slit pore of width capable to accommodate a molecular layer on each side.

In this regards, we focused on controlling the morphology of activated carbon in this study in order to obtain the high capacity of hydrogen storage. Specially, in our study, regenerated cellulose fibers from natural plants such as rice straws, paper mulberry and so on had been used as the source materials of activated carbon. Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 nm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/Nmethylmorpholine-N-oxide(MMO) solution. X-ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). From the regenerated cellulose fiber based on rice straw, mesoporous carbon fiber was prepared by carbonization. This observation indicates that a potential utility of rice straw as a new mesoporous materials. On the other hand, in order to enhance the mesoporosity of activated carbon fibers, the regenerated cellulose fibers were also chemically treated with KOH. It was found that the relative surface area of activated carbon fibers were increased in proportion with the concentration of KOH solution, 1567 m²/g, 2153 m²/g and 2260 m²/g for 2 M, 4 M, and 8 M of KOH solution, respectively. In addition, activated carbon fibers treated with 8M of KOH solution showed the largest hydrogen strorage capactity, 4.359 wt%.

( 출처 : SUMMARY 7p )

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 초록 ... 3
• 요 약 문 ... 4
• S U M M A R Y ... 7
• C O N T E N T S ... 10
• 목차 ... 11
• 제 1 장 연구개발과제의 개요 ... 12
• 제 1 절 연구개발의 목적 및 필요성 ... 12
• 제 2 절 연구개발 목표 및 범위 ... 15
• 제 3 절 정량적 연구목표 ... 16
• 제 4 절 평가의 착안점 및 기준 ... 17
• 제 2 장 국내외 기술개발 현황 ... 18
• 제 1 절 국내외 기술개발 현황 ... 18
• 제 2 절 현 보유 기술대비 국내외 기술개발 현황 비교 ... 20
• 제 3 장 연구개발 수행 내용 및 결과 ... 21
• 제 1 절 연구개발 수행 내용 ... 21
• 제 2 절 결론 ... 57
• 제 3 절 대표연구실적 사례 ... 58
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 59
• 제 1 절 목표 달성도 ... 59
• 제 2 절 관련분야에의 기여도 ... 63
• 제 5 장 연구개발결과의 활용계획 ... 65
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 66
• 제 7 장 참고문헌 ... 68
• 끝페이지 ... 70