Facile Solution Synthesis of Colloidal CeO2 Quantum dots For Enhanced Photoelectrochemical and Anti-corrosion performances

Author(s)
서동현
Alternative Author(s)
Seo Donghyun
Advisor
조인선
Department
일반대학원 에너지시스템학과
Publisher
The Graduate School, Ajou University
Publication Year
2022-02
Language
eng
Keyword
AZ31BAnti-corrosion coatingBiVO4colloidal CeO2photoelectrochemical water splitting
Abstract
이 연구에서는 구연산을 킬레이트 및 안정제로 암모니아수를 산화제로 사용하여 용액공정으로 쉽게 CeO2 quantum dot (Ce-QDs) 콜로이드 용액을 합성했다 합성된 Ce-QD는 물 속에서 매우 안정적으로 분산되었고 , 각각 평균 1.8, 2.3, 3.0 nm 의 크기로 광전기화학 수전해 photoelectrochemical water splitting, PEC water splitting) 에 사용되었다. 콜로이드 Ce-QDs 는 BiVO4 (BVO) 광음극에 스핀 코팅 기법을 사용하여 균일하게 증착 되었다 Ce-QDs 가 증착 된 BVO (Ce-QDs/BVO) 는 인공 태양 조명 아래에서 CoOx 촉매와 함께 사용함으로써 BVO 전극 (~0.6 m A/cm 2 보다 약 8 배 높은 4.0 mA/cm2의 높은 광전류밀도를 달성하였다 게다가 이 전극은 PBS 전해질에서 진행한 안정성 실험에서 약 70 % 의 손실을 보였으며 1.23 V vs. RHE 에서 89 % 의 높은 산소 생산 효율을 보여주었다 뿐만 아니라 Ce-QDs 는 금속의 부식을 방지하기 위해서도 사용되었으며, AZ31B 마그네슘 합금에 적용하였다 AZ31B 에 Ce-QDs 가 증착 됨으로써 3.5 wt% NaCl 전해질에서 부식속도 감소 부식 저항 증가 등의 효과를 보여주었다 이러한 결 과를 통해 이 연구에 사용된 Ce-QDs 합성 방법은 비용 대면적 등에 효과적이며 PEC, 방식 등 다양한 분야에 적용이 가능함을 보여주었다
Alternative Abstract
In this work, synthesized colloidal CeO2 quantum dots (Ce-QDs) via a facile aqueous solution method using citric acid as a chelating/stabilizing agent and ammonia as an oxidant. The Ce-QDs with an average size of 1.8, 2.3, and 3.0 nm were well-dispersed in the aqueous solution with high stability. The photoelectrochemical water-splitting activity of the Ce-QDs films was investigated. The colloidal Ce-QDs were spin-coated onto BiVO4 (BVO) photoanode, allowing homogeneous and uniform deposition of Ce-QDs on the BVO (Ce-QDs/BVO) photoanode. This Ce-QDs/BVO photoanode exhibited enhanced photoelectrochemical activity, achieving a high photocurrent density of 4.0 mA/cm2 with CoOx co-catalyst deposition under simulated sunlight illumination, which is eight times higher than pristine BVO photoanode (~0.6 mA/cm2). Besides, this structure showed much improved stability, whereas BVO had 70% stability loss, with highest oxygen evolution faradaic efficiency of 89% at 1.23 V versus the reversible hydrogen electrode in the phosphate buffer solution (pH 7.4). Besides, the Ce-QDs were applied to AZ31B magnesium alloy to investigate its corrosion inhibition behavior. I found that the corrosion resistance of Ce-QDs/AZ31B increased by surface passivation, thereby reducing corrosion of AZ31B to a greater extent. These results demonstrate that synthesis methodology is promising for the cost-effective and large-scale synthesis of Ce-QDs with uniform size for diverse (photo)electrochemical and anti-corrosion applications.
URI
https://dspace.ajou.ac.kr/handle/2018.oak/21042
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Graduate School of Ajou University > Department of Energy Systems > 3. Theses(Master)
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