CdSナノロド-[FeFe]ヒドロゲネーゼ複合体によるH2生成のための光化学プロセスの特徴付け
Katherine A Brown1, Molly B Wilker, Marko Boehm
1Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States.
Journal of the American Chemical Society
|February 23, 2012
まとめ
私たちは,太陽エネルギーを効率的に水素燃料に変換するCdS:CaI複合体を作成しました. これらの複合体は高回転率と光子変換効率を示しており,その活動は酵素の速度ではなく,光の吸収によって制限されています.
科学分野:
- 材料科学 材料科学とは
- バイオカタリシス バイオカタリシス
- フォトケミストリー フォトケミストリー
背景:
- 水素の生産は,再生可能エネルギーにとって極めて重要です.
- 効率的な光触媒の開発は,太陽光燃料発電の鍵です.
- 酵素-バイオマテリアルハイブリッドは,新しい触媒経路を提供する.
研究 の 目的:
- 光触媒的水素生成のためのCdS:CaI複合体を調査する.
- H2の進化に影響を与えるメカニズム的および組成的要因を理解する.
- 重要なパラメータを制御することによって,光触媒活動を最適化します.
主な方法:
- 3-メルカプトプロピオニオン酸 (MPA) で封じられたCdSナノロッドの合成.
- CdSナノロッドをクロストリジウムアセトブチリキュム[FeFe]-ヒドロゲナーゼI (CaI) で複合する.
- 異なる条件 (モール比,ドナー濃度,光の強度) の下で光触媒によるH2生成の特徴.
主要な成果:
- CdS:CaI複合体は,高いCaI回転周波数 (380~900s−1) と光子変換効率 (最大20%) を達成した.
- 自己組み立ては静電的に駆動され,H2の生産は光と犠牲のドナーに依存した.
- H2の生成速度は,シミュレートされた太陽流動下で,CaIのターンオーバーではなく,光子の吸収によって制限されました.
- MPAの光酸化によるCaI無活性化により,光触媒活性が4時間後に失われました.
結論:
- CdS:CaI複合体は,H2生成のための効果的な光触媒である.
- アセンブリと反応メカニズムを理解することは,パフォーマンスを最適化するために不可欠です.
- リガンドの光酸化は,長期的な安定性に対する課題であり,さらなる研究が必要である.
関連する概念動画
Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
Photosystem I
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The Z-Scheme of Electron Transport in Photosynthesis
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
Reduction of Alkenes: Catalytic Hydrogenation
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...


![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)