This study interrogated multi-layer heterojunction anodes were interrogated for potential applications to water treatment. The multi-layer anodes with outer layers of SnO2/Bi2O3 and/or TiO2/Bi2O3 onto IrO2/Ta2O5 electrodes were prepared by thermal decomposition and characterized in terms of reactive chlorine species (RCS) generation in 50 mM NaCl solutions. The IrO2/Ta2O5 layer on Ti substrate (Anode 1) primarily served as an electron shuttle. The current efficiency (CE) and energy efficiency (EE) for RCS generation were significantly enhanced by the further coating of SnO2/Bi2O3 (Anode 2) and TiO2/Bi2O3 (Anode 3) layers onto the Anode 1, despite moderate losses in electrical conductivity and active surface area. The CE of the Anode 3 was found to show the highest RCS generation rate, whereas the multi-junction architecture (Anode 4, sequential coating of IrO2/Ta2O5, SnO2/Bi2O3, and TiO2/Bi2O3) showed marginal improvement. The microscopic observations indicated that the outer TiO2/Bi2O3 could form a crack-free layer by an incorporation of anatase TiO2 particles, potentially increasing the service life of the anode. The results of this study are expected to broaden the usage of dimensionally stable anodes in water treatment with an enhanced RCS generation and lifetime.

ABSTRACT
 1. 서 론
 2. 재료 및 방법
  2.1 IrO2 기반 헤태로 접합 산화 전극 제조 방법
  2.2 전기적 분석
  2.3 활성 염소종 발생효율 평가
  2.4 재료 분석
 3. 결과 및 고찰
  3.1 전기적 특성 분석
  3.2 전극 구성에 따른 활성 염소종 발생 특성 분석
  3.3 전극 표면 특성 분석
 4. 결 론
 References

• 홍석화(포항공과대학교 환경공학부) | Sukhwa Hong (Division of Environmental Science and Engineering, Pohang University of Science and Technology)
• 조강우(포항공과대학교 환경공학부) | Kangwoo Cho (Division of Environmental Science and Engineering, Pohang University of Science and Technology) Corresponding autho