알칼라인 수전해 장치에서 안정성 향상을 위한 니켈-철 기반 이중기능 전극의 편향 수정에 관한 연구

다국어 초록 (Multilingual Abstract)

Bias Modulation of Ni–Fe-based Bifunctional Electrodes for Enhancing Stability in Alkaline Water Electrolyzer Han Seo Im Department of Chemistry, Kyung Hee University Nickel-iron (Ni–Fe)-based electrodes are among the most promising materials for oxygen evolution reaction (OER) in alkaline environments, demonstrating superior electrocatalytic activity compared to Pt-group metals. In alkaline water electrolyzers, OER typically requires higher overpotentials than hydrogen evolution reaction (HER), making it the rate-determining step that significantly impacts overall electrolyzer efficiency. However, practical deployment of Ni– Fe-based electrodes is constrained by their limited long-term stability, primarily due to Fe ion dissolution under oxidative conditions. Here, we present a bias modulation strategy utilizing a bifunctional Zn-doped Ni–Fe-based electrode, synthesized via a modified Zn-phosphating method (Zn;NiFePOxHy), wherein the applied bias periodically alternates between OER and HER conditions. This approach not only mitigates electrochemical stress on the catalytic layers but also induces surface reconstruction during oxidative and reductive cycling. Under chronopotentiometric operation, the Zn;NiFePOxHy electrode demonstrates sustained performance over 150 hours across a current density range of 100 to 1000 mA cm−2, with notably enhanced HER activity compared to continuous unidirectional biasing. While bias modulation is applicable to conventional NiFeOxHy electrodes, the Zn;NiFePOxHy system extends the effective modulation duration to 5 hours, owing to its intrinsically improved stability and activity. With mechanical resolution of H2 and O2 gas crossover issues, this bias modulation approach could represent a significant advancement toward enhancing cell efficiency in alkaline water electrolysis under industrially relevant conditions.

목차 (Table of Contents)

• 제1 장 서론 1
• 1.1 연구 배경 1
• 제2 장 실험 8
• 2.1 시약 및 기기 8
• 2.1.1 시약 8
• 2.1.2 기기 9
• 2.2 실험 방법 10
• 2.2.1 전극 제작 원리 및 과정 10
• 2.2.2 전기화학적 성능 및 장기안정성 평가 12
• 제3 장 결과 및 고찰 15
• 3.1 전기화학적 활성화 전위 조절이 OER 및 HER 전기촉매 활성에 미치는 영향 15
• 3.2 주기적 편향 수정을 통한 물 전기분해 반응에 대한 100시간 내구성 실험 22
• 3.3 Zn;NiFePOxHy의 전기화학적 표면 재구성 27
• 3.3.1 편향 수정에 따른 TEM 분석 결과 27
• 3.3.2 편향 수정에 따른 XPS 분석 결과 36
• 3.3.3 편향 수정에 따른 Zn;NiFePOxHy 전극 표면 구조 변화 요약 40
• 3.4 고전류 밀도에서 편향 수정을 적용한 흐름 셀 및 단위 전지 실험 43
• 제4 장 결론 49
• 참고문헌 50