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Controlled Growth and Application for the Anodization of Tin and Iron
양극산화를 통한 주석과 철 산화물의 성장 제어와 응용

DC Field Value Language
dc.contributor.advisor손병혁-
dc.contributor.advisorWolfgang Tremel-
dc.contributor.author모리 닐스-
dc.date.accessioned2017-07-14T05:56:36Z-
dc.date.available2017-07-14T05:56:36Z-
dc.date.issued2016-02-
dc.identifier.other000000132650-
dc.identifier.urihttps://hdl.handle.net/10371/125300-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 화학부 고분자화학 전공, 2016. 2. Wolfgang Tremel.-
dc.description.abstract나노 화학영역은 높은 효율 덕분에 다양한 분야에서 활발히 연구 중이다. 전기화학적 양극산화는 손쉬운 제어와 스케일 업뿐만 아니라 넓은 응용분야를 갖고 있기 때문에, 나노 화학 영역에서 가장 촉망 받는 분야로 그 관심이 커지고 있다. 하지만, 현재까지의 연구로는 박막의 품질 향상과 응용분야에 따른 물질의 기공크기의 변화와 같은 단순한 제어만 가능한 상태이며, 다양한 금속 물질을 이용한 기공형성에 대한 연구는 아직 미흡하다. 따라서, 본 연구에서는 전기화학적 양극산화를 이용한 주석과 철의 자기 정렬 나노 기공 금속박막의 제조를 중점적으로 다루었다.
2장에서는, 양극산화를 이용한 스폰지 타입의 주석산화물 형성에 대한 연구를 진행하였다. 전기 연마 방법과 온도를 조합하여 상용화된 주석 호일을 성공적으로 연마할 수 있었다. 연이여, 다양한 요소들을 조직적으로 변화시켰으며, 레이저현미경, 주사전자현미경, X-선 미세회절 등의 장비를 이용하여 그 구조를 분석하였다. 완충 용액의 도입을 통하여 균일하고 무결점의 스폰지형의 주석산화막을 성공적으로 합성할 수 있었다.
완충용액의 도입을 통하여 주석 산화물의 침전으로 인한 표면부동화를 방지함으로써 저압에서의 양극산화가 가능했다. 그 결과, 라멜라 Sn/SnO2 코어셀 구조를 발견할 수 있었다. 3장에서는 라멜라 구조의 성장 메커니즘을 연구하였다. 각각의 구조는 주사전자현미경과 X선 광전자 분광법, 뫼스바우어 분광법을 이용하여 분석하였다.
스폰지 구조와 라멜라 구조의 주석 산화물의 특성을 비교한 연구를 4장에 정리하였다 .광촉매, 양쪽성, 항균성 등의 특성을 비교하기 위해, UV 측정을 통한 Rhodamine B의 흡광도의 저하를 확인하고 컨택앵글 측정 및 E. coli 균의 광산화를 살펴 보았다.
5장에서는, 스폰지 구조의 주석 산화막에 탄소를 코팅하여 배터리의 양극으로 응용하는 실험을 진행했다. 주석을 구리 호일 위에 전착하고 양극산화를 한 후, 탄소코팅 전후의 조성과 구조를 주사전자현미경, X-선 미세회절, EDX, X 선 광전자 분광법, 라만 분광법을 이용하여 비교 분석 하였다. 추가적으로 박막의 전기화학적 성질을 리튬이온전지의 반쪽셀에 적용하여 분석하였다.
나노 기공 산화철의 합성은 6장에서 토론하였다. 자가 제작한 교반 시스템을 이용하여 상용화된 철을 연마하였다. 연속적으로 양극산화를 하여 다양한 요소들을 확인하고 새로운 성장이론에 대한 연구를 진행하였다.
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dc.description.abstractIn modern research, nanochemistry is one of the most studied topics because of the benefit of increased efficiency in almost every application. In this field, the electrochemical anodization has attracted an growing interest in recent years not only due to the broad range of possible applications but also because of the easy control and up scalability of the process. While to this point, many metals have been successfully anodized the theory behind the pore formation is not yet fully understood. Only with this knowledge, advancements in film quality are possible, widening the range of applications for these tailor made materials. The preparation of self-ordered nanoporous metal oxide films from tin and iron by electrochemical anodization is in the focus of this work.
In chapter 2, the synthesis of sponge-like SnOx by anodization has been investigated. By a combination of tempering and a single or three-step electropolishing method, commercially available tin foil was successfully smoothed. Subsequently, different parameters were varied systematically and the observed structures were characterized using laser microscopy, scanning electron microscopy and X-ray microdiffraction. The application of a buffered solution resulted in the successful synthesis of a homogeneous and defect-free sponge-like SnOx film.
With the use of the buffered solution, anodization at low-applied voltages became possible, to this point inhibited due to a passivation of the surface by the precipitation of tin oxalate. This resulted in the discovery of a lamellar Sn/SnO2 core-shell structure. In chapter 3, the growth mechanism of the lamellae is described. The structure was investigated by the use of scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray microdiffraction and Mössbauer spectroscopy.
A comparison of application properties of the SnOx sponge and the lamellar Sn/SnO2 structure is presented in chapter 4. Efficiencies in photocatalysis, amphiphilic behavior and antimicrobial properties were explored by the degradation of rhodamine B, contact-angle goniometry and the photooxidation of E. coli bacteria respectively.
In chapter 5, application of the SnOx sponge as a battery anode material via a carbon coating approach was investigated. After electrodeposition on a copper foil and anodization, the film was studied before and after coating via scanning electron microscopy, X-ray microdiffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and raman spectroscopy. Furthermore, the film was characterized electrochemically by applying it as an anode in a lithium-ion battery half-cell setup.
The synthesis of nanoporous iron oxide has been investigated in chapter 6. By the use of a custom stirring setup, commercially available iron foils were successfully smoothed. Subsequently, the anodization reaction was examined by the systematic variation of different parameters and a new theory for the growth of the nanoporous iron oxide structure is presented.
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dc.description.tableofcontents1 Introduction 7
1.1 General Interest 7
1.2 Theory of electrochemical anodization 9
1.2.1 Electrochemical oxidation reaction 9
1.2.2 Valve metal theory 11
1.2.3 Electrical fieldDassisted oxide dissolution 12
1.2.4 Anodic protection 14
1.3 Tin dioxide 17
1.4 Iron (III) oxide 18
1.5 Aims of the Project 19
1.6 References 21

2 Controlled Anodization for the Synthesis of Smooth Nanoporous Tin Oxide Films 27
2.1 Introduction 27
2.2 Experimental 28
2.2.1 Materials 28
2.2.2 Tempering 28
2.2.3 Experimental Setup 28
2.2.4 Sample Preparation 30
2.2.5 Characterization 31
2.3 Results and Discussion 33
2.3.1 Tempering 33
2.3.2 Electropolishing 36
2.4 Anodization 45
2.4.1 Aqueous Oxalic Acid Electrolyte 45
2.4.2 DiDPotassium Oxalate Buffered Solutions 50
2.5 Conclusion 57
2.6 References 59

3 SelfUOrganized Arrays of SnO2 Lamellae: Synthesis and Growth Mechanism 61
3.1 Introduction 61
3.2 Experimental 63
3.2.1 Materials 63
3.2.2 Synthesis 63
3.2.3 Characterization 64
3.3 Results and Discussion 66
3.3.1 Structural and physical characterization of the anodization layer 66
3.3.2 Growth mechanism of the SnO2 lamellae 70
3.4 Conclusions 83
3.5 References 85

4 Application of SelfUOrganizing Arrays of SnO2 Microplates with Enhanced Photocatalytic and Antimicrobial Properties in Comparison to SpongeUlike SnOx 89
4.1 Introduction 89
4.2 Experimental 91
4.2.1 Materials 91
4.2.2 Synthesis 91
4.2.3 Characterization 92
4.3 Results and Discussion 94
4.3.1 Photocatalytic activity 95
4.3.2 Wetting behavior 97
4.3.3 Antibacterial behavior 99
4.4 Conclusions 102
4.5 References 103

5 Synthesis and Characterization of Carbon Coated SpongeUlike Tin Oxide Films and Their Application as Electrode Materials in Lithium Ion Batteries 109
5.1 Introduction 109
5.2 Experimental 112
5.2.1 Synthesis of SnOx Sponges on Copper Foil 112
5.2.2 Carbon Coating of SnOx Sponges 112
5.2.3 Characterization 113
5.3 Results and Discussion 116
5.3.1 Structural and morphological characterization of carbon coated SnOx sponges 116
5.3.2 Electrochemical characterization of carbon coated SnOx sponges 126
5.4 Conclusions 131
5.5 References 133

6 Controlled Synthesis and Growth Mechanism for the Anodization of Iron 137
6.1 Introduction 137
6.2 Experimental 139
6.2.1 Materials 139
6.2.2 Experimental Setup 139
6.2.3 Sample Preparation 140
6.2.4 Characterization 141
6.3 Results and Discussion 142
6.3.1 Electropolishing 142
6.3.2 Anodization 145
6.3.3 Growth Mechanism 148
6.3.4 Cross Section Measurement 157
6.3.5 Modulation of Anodic Bias 158
6.3.6 Modulation of Water Concentration 159
6.3.7 Stirring 161
6.3.8 Tempering 163
6.4 Conclusion 164
6.5 References 166

7 Summary and Outlook 168

Appendix 175

List!of!Figures 195

List!of!Tables 207

List!of!publications 209
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dc.formatapplication/pdf-
dc.format.extent65429185 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjecttin oxide-
dc.subjectiron oxide-
dc.subjectanodization-
dc.subjectgrowth mechanism-
dc.subjectLi-ion battery-
dc.subjectself-cleaning surfaces-
dc.subject.ddc540-
dc.titleControlled Growth and Application for the Anodization of Tin and Iron-
dc.title.alternative양극산화를 통한 주석과 철 산화물의 성장 제어와 응용-
dc.typeThesis-
dc.contributor.AlternativeAuthorNils Mohri-
dc.description.degreeDoctor-
dc.citation.pages211-
dc.contributor.affiliation자연과학대학 화학부-
dc.date.awarded2016-02-
Appears in Collections:
College of Natural Sciences (자연과학대학)Dept. of Chemistry (화학부)Theses (Ph.D. / Sc.D._화학부)
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