View : 792 Download: 0

Full metadata record

DC Field Value Language
dc.contributor.advisor황성주-
dc.contributor.author김인영-
dc.creator김인영-
dc.date.accessioned2016-08-26T04:08:20Z-
dc.date.available2016-08-26T04:08:20Z-
dc.date.issued2014-
dc.identifier.otherOAK-000000085117-
dc.identifier.urihttps://dspace.ewha.ac.kr/handle/2015.oak/211030-
dc.identifier.urihttp://dcollection.ewha.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000085117-
dc.description.abstractThe various nanosheet-based hybrid materials are prepared by soft-chemical synthetic routes such as solvothermal method, room-temperature reaction, and the exfoliation-reassembling process. The incorporation of inorganic nanosheet with 0D/1D/2D inorganic- and organic- nanostructures creates not only a strong coupling between two components but also a high porosity originated from the stacked nanosheets. Interestingly, the intimate hybridization of inorganic nanosheet and graphene induces unexpected physicochemical phenomenon in terms of phase transition behavior, optical properties, and thermal stabilities. Diverse functionalities of these nanosheet-based hybrids are discussed with an emphasis for the energy and environmental applications such as Li-ion batteries, supercapacitors, photocatalysts, gas adsorbents, antibacterial membranes, and DNA reservoirs. In chapter I, general introduction is described for understanding of the present research. This chapter classifies the layered materials as layered metal oxide, layered double hydroxide, layered metal chalcogenide, and graphene. Brief explanation of diverse application field for nanohybrids is also included in this chapter. In chapter II, Li4Ti5O12 nanosheetsSnO2 and grapheneLi4Ti5O12 hybrids, and 2D aggregates of TiO2 are synthesized and applied as an anode material for Li-ion batteries. The accommodation of SnO2 nanocrystals in the porous structure of assembled Li4Ti5O12 nanosheets yields a tolerance for SnO2 volume change during electrochemical cycling. The hybridization with graphene induces the enhancement of the electrical conductivity of Li4Ti5O12, leading to the improvement of the electrode performance of graphene-Li4Ti¬5O12. Also, the 2D aggregates of TiO2 nanoparticles are profitable for the Li+ ion transport through the enlargement of mesopores. The present findings demonstrate the beneficial effect of incorporation of nanosheets on the electrode material for Li-ion batteries. In chapter III, the 2D nanoplates of -MnO2 are synthesized at room temperature via one-pot oxidation reaction. Also, Li/graphenelayered MnO2 is prepared by the flocculation of mixed colloidal suspension of exfoliated graphene and layered MnO2 nanosheets with Li+ ions. Since the -MnO2 nanosheets have the largest surface area and layered structure favorable for cation intercalation, the present MnO2 nanosheet-based materials shows the large specific capacitance for supercapacitors. In chapter IV, strongly coupled hybrids of layered titanategraphene are synthesized by electrostatically derived self-assembly between negatively charged graphene nanosheets and positively charged TiO2 nanosols, which is then followed by a phase transition of the anatase TiO2 component into layered titanate. The formation of hybrids with graphene nanosheets is effective not only in promoting the phase transition of anatase TiO2 into layered titanate, but also in improving the thermal stability of the layered titanate, indicating the role of graphene nanosheets as an agent for directing and stabilizing layered structures. As a consequence of fairly strong electronic coupling, the layered titanate-graphene hybrids are much more active than unhybridized layered titanate for the photodegradation of organic pollutant, highlighting the usefulness of graphene hybridization in improving the photocatalyst performance of layered titanate. In chapter V, a new type of efficient CO2 / H2 absorbent with improved thermal stability is synthesized via self-assembly between inorganic nanosheets and two kinds of 0D inorganic nanoclusters. The co-pillaring of basic CdO with Cr2O3 is fairly effective at increasing a proportion of micropores and reactivity for CO2 molecules and at improving the thermal stability of the resulting porous structure. Taking into account an excellent thermal stability of the inorganic compounds, the co-pillaring of basic metal oxide into inorganic layered materials can provide a very powerful way of developing thermally stable CO2 adsorbents. In chapter VI, freestanding hybrid film of graphenelayered titanate is fabricated and applied as the antibacterial membranes. Also, the surface-modified cationic layered titanate nanosheet is used for reliable DNA reservoir. Since the almost bio-molecules possess negative charge, positively surface- modified inorganic nanosheet opens a new chapter to novel intercalative hybrids materials for biotechnology. Finally, chapter VII provides the overall conclusion of this work and prospect for the exploration of novel nanosheet-based functional materials.;다양한 나노시트 기반 혼성체가 용매열 합성, 상온 합성, 박리화-재조합 반응과 같은 저온, 저에너지 합성법에 의해 만들어졌다. 0차원/1차원/2차원 무기 또는 유기 나노구조체에 무기 나노시트를 혼성화하는 것은 두 성분 간 강한 결합을 창조할 뿐만 아니라 나노시트의 쌓임에서 기인한 높은 다공성을 만들어낸다. 흥미롭게도, 무기 나노시트와 그래핀 간 밀접한 결합은 상전이 양상, 광학적 성질, 열적 안정성과 같은 측면에서 예상하지 못한 새로운 물리화학적 현상을 유발한다. 리튬 이온 전지, 초고용량 캐패시터, 광촉매, 기체 흡착제, 항균 필름, DNA 저장체와 같은 에너지 및 환경 분야의 중요성과 함께 나노시트 기반 혼성체의 이러한 분야로의 다양한 기능성이 기술되었다. I 단원에서는 본 연구의 이해를 돕기위한 일반적 지식이 서술되어있다. 이 단원은 층상물질을 층상 금속산화물, 이중층 수산화물, 층상 금속 칼코게나이드, 그리고 그래핀으로 분류하고 있다. 나노혼성체가 응용될 수 있는 다양한 분야에 대한 간단한 설명 또한 이 단원에 포함되어 있다. II 단원에서는 Li4Ti5O12 나노시트-SnO2 혼성체, 그래핀- Li4Ti5O12 혼성체, 그리고 TiO2 2차원 정렬체를 합성하여 리튬 이온 전지의 음극소재로서 이용하였다. 재조합된 Li4Ti5O12 나노시트의 다공구조 안에 SnO2 나노입자를 함입하는 것은 전기화학적 충방전 시 SnO¬2의 부피 변화를 방지한다. 그래핀과 혼성화하는 것은 Li4Ti5O12의 전기 전도도를 증가시키며, 그 결과 그래핀-Li4Ti5O12의 전극 성능이 향상된다. 또한, TiO2 나노입자의 2차원 정렬체는 메조 기공의 증대를 통한 Li+ 이온 수송에 매우 효과적이다. 이러한 결과들은 나노시트의 도입이 리튬 이온 전지의 전극 물질에 긍정적인 영향을 미친다는 것을 주장한다. III 단원에서는 -MnO2 2차원 나노판을 단 한번의 산화 반응을 통하여 실온에서 합성하였다. 또한 그래핀과 층상 MnO2 나노시트가 혼합된 콜로이드와 Li+ 이온의 응집반응을 통해 Li/그래핀-층상 MnO2을 합성하였다. -MnO2 나노시트가 큰 비표면적과 양이온 삽입에 유리한 층상구조를 가지고 있기 때문에 이러한 MnO2 나노시트 기반 소재들은 큰 슈퍼캐패시터 용량을 보여준다. IV 단원에서는 강하게 결합된 층상 티탄산화물-그래핀 혼성체가 음전하를 띠는 그래핀 나노시트와 양전하를 띠는 TiO2 나노졸 사이의 정전기기적 재조합 반응에 뒤이은 애나테이즈 TiO2 성분의 층상 티탄산화물로의 상전이 의해 합성되었다. 그래핀 나노시트와의 혼성체 형성은 애나테이즈 TiO2의 층상 티탄산화물로의 상전이를 촉진뿐만 아니라 층상 티탄산화물의 열적 안정성을 향상시키는데도 효과적이다. 상당히 강한 전자 결합의 결과로서 층상 티탄산화물-그래핀 혼성체는 유기 오염물의 광분해에 있어서 혼성화되지 않은 층상 티탄산화물보다 더 활성이 좋다. 이는 층상 티탄산화물의 광촉매 활성을 증대시키기 위해 그래핀의 혼성화가 유용함을 나타낸다. V 단원에서는 향상된 열적 안정성을 갖는 새로운 타입의 CO2 및 H2 고효율 흡착제를 무기 나노시트와 두 종류의 0차원 무기 나노클러스터를 재조합하여 합성하였다. Cr2O3와 염기성의 CdO의 공동 기둥화는 마이크로 기공의 비율과 CO2 분자와의 반응성을 높이고, 얻어진 다공 구조의 열적 안정성을 증진시키는데 꽤 효과적이다. 무기 화합물의 우수한 열적 안정성을 고려하면, 무기 층상 물질 내 염기성 금속 산화물의 공동 기둥화가 높은 온도에서 안정한 CO2 흡착제를 개발하는데 꽤 효과적인 방법이 될 수 있다. VI 단원에서는 그래핀-층상 티탄산화물의 혼성 필름을 제조하여 항균 멤브레인으로서 응용하였다. 또한 표면개질된 양이온성 층상 티탄산화물 나노시트를 우수한 DNA 저장체로서 사용하였다. 대부분의 생체 분자들이 음전하를 띠기 때문에 양전하를 띠는 표면개질된 무기 나노시트는 생명공학 분야에서 새로운 층간삽입 혼성 소재에 대한 새로운 장을 연다. 마지막으로 VII 단원에서는 본 연구의 종합적인 결론과 새로운 나노시트 기반 기능성 소재 연구에 대한 전망을 제시한다.-
dc.description.tableofcontentsI. General introduction 1 I.1. Inorganic layered compound 2 I.1.1. Layered metal oxide 4 I.1.2. Layered double hydroxide 9 I.1.3. Layered metal chalcogenide 11 I.2. Graphene 13 I.2.1. Synthetic methods of graphene 15 I.2.1.1. Mechanical cleavage 15 I.2.1.2. Chemical oxidation and reduction method 16 I.2.2. Chemical structure and physicochemical properties of reduced graphene oxide (rG-O) 18 I.2.2.1. Chemical structure of graphite oxide -18 I.2.2.2. Chemical structure of reduced graphene oxide 20 I.2.2.3. Physicochemical properties of reduced graphene oxide 22 I.3. Energy and environmental technologies 24 I.3.1. Li-ion batteries 25 I.3.2. Supercapacitors 26 I.3.3. Photocatalysts 28 I.3.4. Gas adsorbents 29 I.3.5. Antibacterial membrane 30 I.3.6. DNA resorvoirs 31 I.4. References and notes 32 II. Nanosheet-based hybrids for Li-ion batteries 34 II.1. Electrochemically active nanocomposites of Li4Ti5O12 2D nano- sheets and SnO2 0D nanocrystals with improved electrode performance 35 II.1.1. Introduction 36 II.1.2. Experimental section 38 II.1.3. Results and discussion 41 II.1.4. Conclusion - 54 II.2. Solvothermal-assisted hybridization between reduced graphene oxide and lithium metal oxides: a facile route to graphene-based composite materials 55 II.2.1. Introduction 56 II.2.2. Experimental section 59 II.2.3. Results and discussion 63 II.2.4. Conclusion - 90 II.3. Graphene nanosheets as a platform for the 2D ordering of metal oxide nanoparticles: Mesoporous 2D aggregate of anatase TiO2 nano- particles with improved electrode performance 92 II.3.1. Introduction 93 II.3.2. Experimental section 95 II.3.3. Results and discussion 97 II.3.4. Conclusion 117 II.4. References and notes 118 III. Nanosheet-based hybrids for supercapacitors 127 III.1. Room temperature synthesis routes to the 2D nanoplates and 1D nanowires/nanorods of manganese oxides with highly stable pseud ocapacitance behaviors 128 III.1.1. Introduction 129 III.1.2. Experimental section 131 III.1.3. Results and discussion 133 III.1.4. Conclusion 152 III.2. Mixed colloidal suspensions of reduced graphene oxide and lay- ered metal oxide nanosheets: Useful precursors for the porous nanoc- posite materials 153 III.2.1. Introduction 154 III.2.2. Experimental section 156 III.2.3. Results and discussion 159 III.2.4. Conclusion 181 III.3. References and notes - 183 IV. Nanosheet-based hybrids for photocatalysts - 189 IV.1. A strong electronic coupling between graphene nanosheets and layered titanate nanoplates: A soft-chemical route to highly porous n-anocomposites with improved photocatalytic activity 190 IV.1.1. Introduction 191 IV.1.2. Experimental section 194 IV.1.3. Results and discussion 198 IV.1.4. Conclusion 220 IV.2. References and notes - 221 V. Nanosheet-based hybrids for gas adsorbents - 225 V.1. New type of efficient CO2 adsorbents with improved thermal stability: Self-assembled nanohybrids with optimized microporosity and gas adsorption function - 226 V.1.1. Introduction 227 V.1.2. Experimental section 229 V.1.3. Results and discussion 231 V.1.4. Conclusion - 247 V.2. References and notes - 248 VI. Nanosheet-based hybrid for bio-application - 252 VI.1. Strongly-coupled hybrid membranes of graphene and layered ti- tanate nanosheets: An effective way to tailor the physicochemical and antibacterial properties of graphene paper 253 VI.1.1. Introduction - 254 VI.1.2. Experimental section 256 VI.1.3. Results and discussion - 257 VI.1.4. Conclusion 271 VI.2. Highly stable nanocontainer for nucleic acids: Reliable protection and deprotection of DNA by cationic metal oxide nanosheets 272 VI.2.1. Introduction - 273 VI.2.2. Experimental section 275 VI.2.3. Results - 278 VI.2.4. Discussion 289 VI.2.5. Conclusion 292 VI.3. References and notes - 293 VII. Overall conclusion and future scope 299 Appendix. Curriculum vitae 302 국문초록 314 감사의 글 317-
dc.formatapplication/pdf-
dc.format.extent10598529 bytes-
dc.languageeng-
dc.publisher이화여자대학교 대학원-
dc.subject.ddc500-
dc.titleNanosheet-based Hybrids for Energy and Environmental Technology-
dc.typeDoctoral Thesis-
dc.title.subtitleA Soft Chemical Route to Strongly Coupled Hybrids with Improved Performance-
dc.format.pagexiii, 319 p.-
dc.identifier.thesisdegreeDoctor-
dc.identifier.major대학원 화학·나노과학과-
dc.date.awarded2014. 2-
Appears in Collections:
일반대학원 > 화학·나노과학과 > Theses_Ph.D
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

BROWSE