Concepcion Javier J, Jurss Jonah W, Templeton Joseph L, Meyer Thomas J
Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA.
Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):17632-5. doi: 10.1073/pnas.0807153105. Epub 2008 Nov 12.
Light-driven water oxidation occurs in oxygenic photosynthesis in photosystem II and provides redox equivalents directed to photosystem I, in which carbon dioxide is reduced. Water oxidation is also essential in artificial photosynthesis and solar fuel-forming reactions, such as water splitting into hydrogen and oxygen (2 H(2)O + 4 h nu --> O(2) + 2 H(2)) or water reduction of CO(2) to methanol (2 H(2)O + CO(2) + 6 h nu --> CH(3)OH + 3/2 O(2)), or hydrocarbons, which could provide clean, renewable energy. The "blue ruthenium dimer," cis,cis-(bpy)(2)(H(2)O)Ru(III)ORu(III)(OH(2))(bpy)(2), was the first well characterized molecule to catalyze water oxidation. On the basis of recent insight into the mechanism, we have devised a strategy for enhancing catalytic rates by using kinetically facile electron-transfer mediators. Rate enhancements by factors of up to approximately 30 have been obtained, and preliminary electrochemical experiments have demonstrated that mediator-assisted electrocatalytic water oxidation is also attainable.
光驱动水氧化发生在光系统II的氧光合作用中，并提供氧化还原当量导向光系统I，在光系统I中二氧化碳被还原。水氧化在人工光合作用和太阳能燃料形成反应中也至关重要，例如水分解成氢气和氧气（2H₂O + 4hν → O₂ + 2H₂）或水将CO₂还原为甲醇（2H₂O + CO₂ + 6hν → CH₃OH + 3/2O₂），或形成碳氢化合物，这可以提供清洁的可再生能源。“蓝色钌二聚体”，顺式，顺式 - (bpy)₂(H₂O)Ru(III)ORu(III)(OH₂)(bpy)₂，是第一个被充分表征的催化水氧化的分子。基于对该机制的最新认识，我们设计了一种通过使用动力学上容易的电子转移介质来提高催化速率的策略。已经获得了高达约30倍的速率增强，并且初步的电化学实验表明介质辅助的电催化水氧化也是可行的。
