EPR Spectroscopy of the Cobalt Water Splitting Catalyst

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。无机化学、生物无机化学和金属有机化学项目的这项研究奖支持加州大学戴维斯分校的R.David Britt教授对简单钴催化剂分解水的结构和机理细节进行的基础研究。麻省理工学院的研究人员最近证实，在中性磷酸盐缓冲液中，Co(II)在极化电极表面自发形成水分解催化剂。这种催化剂提供良好的电流密度、自组装和自修复，在环境条件下在中性pH水中以低过电位运行，并由廉价的、富含地球的材料形成。长期以来，该研究计划一直专注于光合作用中水分解的电子顺磁共振(EPR)研究，其中使用了一个天然的锰簇，该研究计划现在正在使用相同的EPR方法来详细研究钴催化剂。该研究项目正在研究电化学生成的钴催化剂的几何结构和电子结构。各种EPR技术将探测钴离子上未配对电子与钴、磷酸盐和水的磁核的相互作用。该研究项目正在进行现场电化学和快速冷冻淬火来捕获放氧周转过程中的催化剂，并使用同样先进的EPR技术来探索催化机理。学生们对可再生能源和环境问题非常感兴趣。两名无机化学研究生正在进行这个项目的研究。这个无机水分离计划的主题完美地融入了加州大学戴维斯分校PI教授的荣誉普通化学序列。PI在讲座中不断强调正在进行的光合作用放氧复合体以及钴和相关合成复合体的相关科学。一些本科生将在夏季对该项目进行研究。对新型钴催化剂的EPR研究将为这一简单系统的工作原理提供新的见解，从而为其改进指明方向。鉴于我们对清洁和碳中性可再生能源的迫切需求，高效太阳能分水催化剂的开发将作为清洁可再生能源技术的基础。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This research award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports work by Professor R. David Britt at the University of California Davis to carry out fundamental research on structural and mechanistic details of water splitting by a simple cobalt catalyst. Investigators at MIT recently demonstrated that Co(II) in neutral phosphate buffer spontaneously forms a water splitting catalyst on a polarized electrode surface. This catalysis provides good current density, self assembles and self repairs, operates at low overpotential in neutral pH water under ambient conditions, and forms from cheap, earth-abundant materials. The research program has long focused on electron paramagnetic resonance (EPR) studies of water splitting in photosynthesis, where a natural manganese cluster is employed, and the research program is now using the same EPR methods to examine the cobalt catalyst in detail. The research program is examining the geometric and electronic structure of the cobalt catalyst as electrochemically generated. Various EPR techniques will probe the interaction of unpaired electrons on the cobalt ions with magnetic nuclei of cobalt, phosphate, and water. The research program is carrying out in situ electrochemistry and rapid freeze quenching to trap the catalyst during oxygen evolving turnover, and use the same advanced EPR techniques to probe the catalytic mechanism.Students are very motivated by renewable energy and environmental issues. Two Inorganic Chemistry graduate students are conducting research in this program. The topics of this inorganic water splitting program integrate perfectly into the honors general chemistry sequence that the PI is teaching at UC Davis. The PI continually emphasizes the relevance of the ongoing science of the oxygen evolving complex of photosynthesis and of the cobalt and related synthetic complexes in lectures. Some undergraduates will do research on the project during the summer.The EPR studies on the new cobalt catalyst will provide new insights into how this simple system works and thereby indicate directions for its improvement. Given our crucial needs for clean and carbon-neutral renewable energy, the development of efficient solar water splitting catalysts would serve as the basis of a clean renewable energy technology.