S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Theses (Ph.D. / Sc.D._화학생물공학부)
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
- 공과대학 화학생물공학부(에너지환경 화학융합기술전공)
- Issue Date
- 서울대학교 대학원
- Hydroxyl radical; ozone; hydrogen peroxide; boron doped diamond electrode; carbon fiber; solid polymer electrolyte electrolyzer
- 학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부(에너지환경 화학융합기술전공), 2014. 2. 윤제용.
- Electrochemical 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.