第一过渡系列金属元素单核水氧化催化剂的最新进展

水的氧化是光合作用的重要步骤,其提供用于二氧化碳固定的电子和质子,以及生物圈所必需的氧气.在将太阳能转换为化学能的人工光合作用中,设计合成高效稳定的水氧化催化剂是研究的关键.目前的催化体系主要是基于钌和铱等贵金属的金属氧化物纳米颗粒和多核金属配合物.基于钌和铱的单核催化体系近年来也得到了广泛的发展.最近几年,第一过渡系列金属元素单核水氧化催化剂快速得到重视.作为配合物中心原子,它们不仅具有丰富的氧化态,而且因相对充足的蕴藏和较低的开采冶炼成本,其具有钌和铱等贵金属不可比拟的重大优势和广阔的应用前景.本文总结了近几年第一过渡系列金属元素单核水氧化催化剂的进展,并在此基础上,简单讨论了氧—氧键的生成,为进一步设计新颖、具有高催化效率和高稳定性的单核水氧化催化剂提供了理论依据.

Recent advances in mononuclear water oxidation catalysts based on the first row transition metal elements

Water oxidation is a key process in photosynthesis. It provides electrons and protons for the fixation of carbon dioxide and also releases dioxygen that is essential for the biosphere. In photosystem II, the oxygen evolution center, a complex composed of four manganese atoms and one calcium atom, catalyzes the oxidation of water. Design and synthesis of efficient and stable water oxidation catalysts （WOCs） has attracted major attention in the field of artificial photosynthesis. Previous studies focused on nano-structured metal oxides and/or polynuclear metal complexes based on ruthenium and iridium. Mononuclear WOCs containing Ru or Ir have also been extensively developed since 2008, because （1） they can catalyzes the oxidation of water as efficiently as polynuclear systems; （2） their synthesis, characterization and modification are more straightforward; （3） mononuclear WOCs provide a better system for mechanistic studies by both experimental and theoretical methods. Very recently, mononuclear metal complexes with the first row transition metal elements have been shown to catalyze water oxidation efficiently. In addition to the fact that the first row transition metals are earth- abundant and cheap, they also have variable oxidation states for the activation of water. Therefore, mononuclear WOCs based on the first row transition metal elements have the potential for future application in artificial photosynthesis. This article reviewed recent advances in mononuclear WOCs based mainly on the first row transition metal elements. By briefly discussing the formation of oxygen-oxygen bonds, it sheds light on catalytic water oxidation and should benefit the development of novel WOCs that are highly efficient and stable.