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Cu and Cu alloy electrodes for conversion of CO2 to value-added hydrocarbon fuels : 전기화학적 이산화탄소-고부가가치 화합물 전환을 위한 구리 기반 합금 촉매 개발
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 남기태 | - |
| dc.contributor.author | 양기동 | - |
| dc.date.accessioned | 2018-11-12T00:55:06Z | - |
| dc.date.available | 2018-11-12T00:55:06Z | - |
| dc.date.issued | 2018-08 | - |
| dc.identifier.other | 000000152373 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/143051 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2018. 8. 남기태. | - |
| dc.description.abstract | The electrochemical reduction of CO2 to valuable chemicals or fuel can represent a solution for reducing the carbon footprint and closing the unbalanced carbon-cycle. Among currently available materials, Cu based catalyst has been reported to be albe to convert CO2 to various hydrocarbons. However, for its practical implementation, much better selectivity and low overpotential of cathode than that of current state of art is required. Particularly, the production of high-quality hydrocarbon fuels from the cathodic CO2 reduction reaction is the most essential requirement in that those chemicals have high energy contents and compatibility with the existing fuel infrastructure and thereby, can make the overall reaction highly beneficial. To accomplish the ultimate production of value-added hydrocarbon fuels from the abundant and inexpensive CO2, it is critical to control C-C coupling kinetics and its detailed reaciton pathway.
Chapter 2 investigates Cu mesopore electrodes with various pore size and depth as a potential candidate for selectively controlling CO2 to C2 chemical formation and reaction kinetics. While most metal catalysts produce C1 species, such as CO and HCOOH, various hydrocarbons and alcohols comprising more than two carbons have been achieved using Cu based catalysts only. Methods for producing specific C2 reduction outcomes with high selectivity, however, are not amenable thus far. In this work, the morphology effect of a Cu mesopore electrode on the selective production of C2 products, C2H4 or C2H6, is presented. The Cu mesopore electrodes with precisely controlled pore widths and depths were prepared by a thermal deposition process on anodized alumina oxide. By this simple synthesis method, we demonstrated that C2 chemical selectivity can be tuned by systematically altering the morphology. Moreover, supported by computational simulation, we proved that nanomorphology can change the local pH and additionally, retention time of key intermediates by confining the chemicals inside the pore. Chapter 3 investigates CO2 to value-added hydrocarbon fuel conversion on Cu alloy electrode. Natural photosynthesis has ability to produce glucose and its derivatives from CO2 | - |
| dc.description.tableofcontents | Chapter 1 Introduction 1
1.1 The need for mitigating atmospheric CO2 concentration 1 1.2 Artifical photosynthesis for closing broken carbon cycle 7 1.3 Principal of electrochemical CO2 conversion 13 1.3.1 Thermodynamics and kinetics 13 1.3.2 Scaling relationship of intermediate binding energies 15 1.4 CO2 reduction reaction on Cu electrode 23 1.4.1 Intrinsic property of metal electrodes 23 1.4.2 Unique feature of Cu in terms of CO affinity 27 1.4.3 Reaction pathway from CO2 to hydrocarbon product 29 1.5 Previous studies on Cu electrode 32 1.5.1 Size-controlled Cu nanoparticles 33 1.5.2 Under-coordinated high energy facet of Cu 36 1.5.3 Grain boundary density controlled oxide-derived Cu 38 1.5.4 Local pH control on the nano-fabricated Cu 41 1.5.5 Field enhancement on Cu nanowire 44 1.6 The necessity for CO2 to value-added hydrocarbon conversion 47 1.7 Value-added hydrocarbon production from Cu electrode 50 1.7.1 Current status and limitation of Cu electrode 50 1.7.2 Electrochemical C-C coupling reaction 53 1.8 Efficient C-C coupling reaction in nature and synthetic chemistry 56 1.8.1 Lesson from the natural CO2 fixation enzyme 56 1.8.2 Technological attempts to mimic natural carbon cycling 60 1.9 Strategy for efficient electrocatalytic C-C coupling reaction in heterogeneous system 65 1.10 Scope of Thesis 70 1.11 References 73 Chapter 2 Morphology-directed selective production of C2 hycdrocarbon fuels from Cu mesopore electrode 83 2.1 Introduction 83 2.2 Experimental Methods 87 2.2.1 Materials 87 2.2.2 Electrode preparations 87 2.2.3 Evaluation of catalytic properties 88 2.2.3.1 Electrochemical measurements 88 2.2.4.2 Product analysis 89 2.3 Results and Discussion 91 2.3.1 Basic characterization of Cu mesopore electrode 91 2.3.2 CO2 reduction activity of Cu mesopore electrode 97 2.3.3 Product selectivity for CO2 reduction outcome 101 2.3.4 Electrokientic study 108 2.3.4.1 Specific activity analysis 108 2.3.4.2 Electrohydrodynamic study 114 2.3.4.3 Instability model simulation 118 2.3.5 Empirical evidence for local flow field generation 125 2.4 Concluding Remarks 128 2.5 References 129 Chapter 3 Cu Alloy Catalyst for Electrochemical Conversion of CO2 to Value-added Hydrocarbon 133 3.1 Introduction 133 3.2 Previous studies on Cu alloy electrode 136 3.2.1 CO2 to hydrocarbon conversion on Cu electrode 136 3.2.2 Characteristic CO2 reduction performance on alloy electrode 138 3.3 Expected effects from Cu alloy electrocatalyst 140 3.4 Thermodynamic viewpoint on the alloy system 160 3.5 Phase segregated Cu-binary alloy electrode as a CO 2reduction catalyst 162 3.6 Approach 1: Cu-Ag binary alloy catalyst 166 3.7 Experimental Methods 169 3.7.1 Materials 169 3.7.2 Electrode preparations 169 3.7.3 Evaluation of catalytic properties 170 3.7.3.1 Electrochemical measurements in aqueous environment 170 3.7.3.2 Gas product analysis 171 3.7.3.3 Liquid product analysis 171 3.7.3.4 X-ray diffraction 172 3.8 Results and Discussions 173 3.8.1 Basic characterization of Cu-Ag alloy electrode 173 3.8.2 CO2 reduction activity of Cu-Ag alloy 178 3.8.3 Microstructural effect in Cu-Ag 182 3.8.4 Specific activity analysis 185 3.9 Approach 2: Amorphous alloy electrocatalyst 188 3.10 Experimental Methods 193 3.10.1 Materials 193 3.10.2 Electrode preparations 193 3.10.3 Evaluation of catalytic properties 194 3.10.3.1 Electrochemical measurements in non-aqueous environment 194 3.10.3.2 Gas product analysis 195 3.10.3.3 Liquid product analysis 195 3.10.3.4 Mass spectroscopic analysis 196 3.10.3.5 Surface characterization 198 3.10.3.6 X-ray Diffraction (XRD) 198 3.11 Results and Discussions 199 3.11.1 Basic characterization of Cu amorphous alloy electrode 199 3.11.2 CO2 reduction activity of amorphous Cu alloy electrode 205 3.11.3 Possible C3 and C4 chemical formation 208 3.11.4 Polymeric surface product 212 3.12 Concluding Remarks 217 3.13 References 218 Chapter 4. Conclusion 228 Abstract in Korean 230 Research Achievements 232 | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject.ddc | 620.1 | - |
| dc.title | Cu and Cu alloy electrodes for conversion of CO2 to value-added hydrocarbon fuels | - |
| dc.title.alternative | 전기화학적 이산화탄소-고부가가치 화합물 전환을 위한 구리 기반 합금 촉매 개발 | - |
| dc.type | Thesis | - |
| dc.contributor.AlternativeAuthor | Ki Dong Yang | - |
| dc.description.degree | Doctor | - |
| dc.contributor.affiliation | 공과대학 재료공학부 | - |
| dc.date.awarded | 2018-08 | - |
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