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  • 09월 03일 23시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제122회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Orthorhombic NiSe2 Nanocrystals on Si Nanowires for Efficient Photoelectrochemical Water Splitting

2018년 8월 16일 22시 00분 39초
MAT.P-335 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 18일 (목요일) 11:00~12:30
Material Chemistry
저자 및
SuYoung Lee, Jeunghee Park1,*, Eunhee Cha2, SooA Lim3
Deapartment Green Energy Engineering, Hoseo University, Korea
1Department of Materials Chemistry, Korea University, Korea
2Department of Pharmaceutics, Hoseo University, Korea
3Hoseo University, Korea
Photocatalytic water splitting is a vital technology for clean renewable energy. Despite enormous progress, the search for earth-abundant photocatalysts with long-term stability and high catalytic activity is still an important issue. We report three possible polymorphs of nickel selenide (orthorhombic phase NiSe2, cubic phase NiSe2, and hexagonal phase NiSe) as bifunctional catalysts for water-splitting photoelectrochemical (PEC) cells. Photocathodes or photoanodes were fabricated by depositing the nickel selenide nanocrystals onto p- or n-type Si nanowire arrays. Detailed structure analysis reveals that compared to the other two types, the orthorhombic NiSe2 nanocrystals are more metallic and form less surface oxides. As a result, the orthorhombic NiSe2 nanocrystals significantly enhanced the performance of water-splitting PEC cells by increasing the photocurrents and shifting the onset potentials. The high photocurrent is ascribed to the excellent catalytic activity toward water splitting, resulting in a low charge transfer resistance. The onset potential shift can be determined by the shift of the flat-band potential. A large band bending occurs at the electrolyte interface, so that photoelectrons or photoholes are efficiently generated to accelerate the photocatalytic reaction at the active sites of orthorhombic NiSe2. The remarkable bifunctional photocatalytic activity of orthorhombic NiSe2 promises efficient PEC water-splitting.