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CdS nanorod-[FeFe]-hydrogenase複合体における電子移転運動と,光化学的H2生成への影響について
Molly B Wilker1, Katherine E Shinopoulos, Katherine A Brown
1Department of Chemistry and Biochemistry, University of Colorado Boulder , Boulder, Colorado 80309, United States.
Journal of the American Chemical Society
|February 26, 2014
まとめ
カドミウム硫化物ナノ棒 (CdS NRs) と[FeFe]-ヒドロゲネーゼI (CaI) の間の電子伝送運動を研究した. CdS NRsにおける類似の電子伝送と放松率は,H2の生産効率を制限し,改善のための構造的修正を示唆しています.
科学分野:
- 生物物理化学 生物物理化学
- ナノ材料科学 ナノ材料科学
- フォトカタリシスによる.
背景:
- 硫化カドミウムナノ棒 (CdS NRs) と[FeFe]-ヒドロゲンゼI (CaI) の複合体を用いたH2の光化学的生成は,電子ドナーで20%までの量子収量を示しています.
- CdS NRからCaIへの電子伝送 (ET) 運動は,ETの量子効率が最大H2生成率を決定するので,全体的な光化学反応性にとって決定的です.
研究 の 目的:
- CdS NRsにおけるETと電子リラクゼーション経路の競争を調査する.
- 光刺激されたCdS NRからCaIまでのETの速度と量子効率を直接測定する.
- CdS-CaI複合体における電子の注入と輸送の仕組みを理解する.
主な方法:
- トランジエント吸収スペクトロスコピーは,ET運動を直接測定するために使用されました.
- この研究では,CdS NRsとClostridium acetobutylicumからの[FeFe]-水素酵素I (CaI) を光刺激したCdS NRを用いた.
- 実験には,触媒的に活性化および非活性化されているCaIの形態を用いた.
主要な成果:
- CdS NRs (k(CdS)) での電子移転速度の定数 (k(ET)) と電子リラックス速度の定数 (k(CdS)) は,両方が約10(7) s(-1) で比較可能であることが判明しました.
- ETの量子効率は,1:1のモラ比でCaI:CdS NR複合体で42%と決定されました.
- 電子の注入は,遠隔の鉄硫黄群に発生し,続いて,CaIの触媒活性に関係なく,アクセサリー群を通って活性部位への輸送が観察されました.
結論:
- CdS NRsにおけるETと電子放松の比率は,H2の生産効率にボトルネックをもたらします.
- H2の生産効率の向上は,ナノ結晶の構造改変により,k(ET) を増加させ,またはk(CdS) を減少させることで達成することができる.
- この発見は,CdS-CaI複合体における光化学的H2生成を制御する運動経路とその全体的な効率との関係についての洞察を提供します.
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