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Properties and Mechanisms of Electrochemical Reactive Oxygen Species Generation Using a Solid Polymer Electrolyte Electrolyzer : 고체 고분자 전해질 전해조를 이용한 전기화학적 활성산소종 발생 특성 및 메커니즘

DC Field Value Language
dc.contributor.advisor윤제용-
dc.contributor.author최주솔-
dc.date.accessioned2017-07-13T08:48:13Z-
dc.date.available2017-07-13T08:48:13Z-
dc.date.issued2014-02-
dc.identifier.other000000016946-
dc.identifier.urihttps://hdl.handle.net/10371/119854-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부(에너지환경 화학융합기술전공), 2014. 2. 윤제용.-
dc.description.abstractElectrochemical ozone production (EOP) via oxidation of water has attracted attention as an effective technology for a water treatment alternative to the conventional ozonation. The presence of inert supporting electrolytes (SEs) in EOP is essential to increase the electrical conductivity of water, but little is known about the role of SEs in EOP on BDD electrodes. Also, development of electrodes for hydrogen peroxide production via reduction of oxygen was required for simultaneous production of ozone and hydrogen peroxide. In order to expand the knowledge of the effect of SEs on EOP on a BDD electrode and the development of electrodes for hydrogen peroxide production, the following studies were conducted.
First, an effect of SEs on EOP on a BDD electrode was investigated as the solid polymer electrolyte electrolyzer permitting water oxidation even in the absence of SEs was employed. As major results, SEs caused significant suppression of EOP regardless of their types in comparison with that in deionized water, but did not decrease the production of •OH which is intermediate for ozone production and the overall oxidation current. On the other hand, the production of hydrogen peroxide via the combination of •OH was suppressed by the presence of SE. The suppression of EOP by SE is interpreted to be attributed to SE anions hindering the combination of •O on the electrode surface. Based on this suppression effect of SEs, operating conditions for optimal EOP were investigated.
Second, high-yield hydrogen peroxide generation using a membrane electrode assembly (MEA) with a carbon fiber (CF)-coated mesh substrate was investigated in a solid polymer electrolyte electrolyzer. Current efficiency (52%) and power consumption (0.3 Wh∙g-1) for this MEA were 1.5 times higher and 2 times lower than those of reported values (at -0.1 V vs. Ag/AgCl). These significant improvements were presumed to be attributed to enhanced oxygen mass transfer and reduced charge transfer resistance arising from the CF-coated mesh substrate in the MEA. Based on these findings, commercial carbon cloth electrodes were employed for hydrogen peroxide production.		-
dc.description.tableofcontentsCONTENTS
Abstract--------------------------------------------------------------i
Contents------------------------------------------------------------iii
List of Figures----------------------------------------------------vii
List of Tables-----------------------------------------------------xiv
1. Introduction ----------------------------------------------------1
1.1. Research Background ----------------------------------------------2
1.2. Objectives of the study ---------------------------------------------4
2. Literature Review ---------------------------------------------6
2.1. Electrochemical reactive oxygen species generation---------7
2.1.1. Mechanisms of Hydroxyl radical -----------------------------------------7
2.1.2. Mechanisms of Ozone--------------------------------------------------------9
2.1.2.1. Investigation of hydroxyl radical formation----------------------11
2.1.2.2. Investigation of adsorbed oxygen species-------------------------13
2.1.3. Hydrogen peroxide---------------------------------------------------------20
2.2. SPE electrolyzers---------------------------------------------------21
2.2.1. Properties of SPE electrolyzers ------------------------------------21
2.2.2. Membrane electrode assemblies ----------------------------------22
2.2.3. Ozone and hydrogen peroxide production in an SPE electrolyzer------------------------------------------------------------------------------------26
2.2.4. Simultaneous ozone and hydrogen peroxide generation----------67
3. Experimental section-----------------------------------------69
3.1. Chemicals------------------------------------------------------------40
3.1.1. Supporting electrolytes-----------------------------------------------------41
3.2. Electrodes------------------------------------------------------------42
3.2.1. Preparation of a BBD electrode------------------------------------------42
3.2.2. Preparation of a PbO2 electrode--------------------------------------------44
3.2.3. Preparation of a carbon fiber coated electrode-----------------------46
3.2.4. Preparation of carbon cloth electrodes---------------------------------50
3.3. Electrochemical ROS generation-------------------------------------52
3.2.1. Electrochemical ozone generation---------------------------------------52
3.2.2. Electrochemical hydrogen peroxide generation-----------------------53
3.4. Anlaysis-------------------------------------------------------------------------55
3.4.1. Influence of SEs on electrochemical ozone production-----------------55
3.4.2. RNO bleaching for hydroxyl radical formation----------------------56
3.4.3. p-HBA measurement for hydroxyl radical formation---------------57
3.4.4. Electrochemical analysis---------------------------------------------------58
4. Results and discussion---------------------------------------59
4.1. The suppression of electrochemical ozone production by supporting electrolytes on the BDD electrode----------------60
4.1.1. Background--------------------------------------------------------------------60
4.1.2. Effect of the presence of each individual SE on EOP----------------63
4.1.3. Effect of the presence of each individual SE on •OH formation---66
4.1.4. Effect of the presence of each individual SE on oxidation current density in CVs---------------------------------------------------------------69
4.1.5. Effect of SEs on hydrogen peroxide production----------------------74
4.1.6. Mechanisms responsible for the suppression of EOP by the SEs--77
4.1.7. Conclusions-------------------------------------------------------------------79
4.2. Operating conditions for high yield EOP----------------------80
4.2.1. Background-------------------------------------------------------------------80
4.2.2. Influence of electrical conductivity of solution EOP on the BDD and PbO2 electrode---------------------------------------------------------83
4.2.3. Relationship between EOP rate on the BDD electrode and electrical conductivity of solution-----------------------------------------------------87
4.2.4. Electrochemical properties of the BDD and PbO2 electrode-------90
4.2.5. Influence of flow rate, temperature, and applied current on EOP on the BDD and PbO2 electrode---------------------------------------------------96
4.2.6. Conclusions-------------------------------------------------------------------98
4.3. High yield hydrogen peroxide production in a solid polymer electrolyte electrolyzer with a carbon fiber coated mesh substrate-------------------------------------------------------------------------99
4.3.1. Background--------------------------------------------------------------------99
4.3.2. Current efficiency and hydrogen peroxide production in the SPE electrolyzer------------------------------------------------------------------101
4.3.3. LSV and EIS in the SPE electrolyzer------------------------------------105
4.3.4. Conclusions------------------------------------------------------------------109
4.4. Electrolyte-free hydrogen peroxide generation using carbon cloth electrodes in a solid polymer electrolyte electrolyzer-----------------------------------------------------------------------------110
4.4.1. Background-----------------------------------------------------------------110
4.4.2. Current efficiency for carbon cloth electrodes in the SPE electrolyzer-----------------------------------------------------------------113
4.4.3. CVs and Anson plots for CC, 25HC, and 10SC in the SPE electrolyzer-----------------------------------------------------------------117
4.4.4. Conclusions------------------------------------------------------------------121
5. Conclusions----------------------------------------------------122
References--------------------------------------------------------126
Appendix---------------------------------------------------------140
국문 초록--------------------------------------------------------145
감사의 글--------------------------------------------------------147		-
dc.formatapplication/pdf-
dc.format.extent2427506 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectHydroxyl radical-
dc.subjectozone-
dc.subjecthydrogen peroxide-
dc.subjectboron doped diamond electrode-
dc.subjectcarbon fiber-
dc.subjectsolid polymer electrolyte electrolyzer-
dc.subject.ddc660-
dc.titleProperties and Mechanisms of Electrochemical Reactive Oxygen Species Generation Using a Solid Polymer Electrolyte Electrolyzer-
dc.title.alternative고체 고분자 전해질 전해조를 이용한 전기화학적 활성산소종 발생 특성 및 메커니즘-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pagesxiv, 147-
dc.contributor.affiliation공과대학 화학생물공학부(에너지환경 화학융합기술전공)-
dc.date.awarded2014-02-
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