抄録
Visible-light-induced water splitting into hydrogen gas (H2) and oxygen gas (O2) attracts much attention for the development of fossil-fuel-independent energy systems. The water splitting reaction is broken down into its oxidative and reductive half-reactions, which can be studied independently. Generally the development of oxygen-evolving catalysts is more difficult than that of hydrogen evolving ones, since they involve the oxidation of water by 4H+ and 4e-with concomitant formation of an oxygen-oxygen bond. So far, examples of efficient and robust catalysts for water oxidation are very rare. Recently, some robust catalysts for the homogeneous oxidation of water have been reported. Thummel et al. described a new class of diruthenium polypyridyl complexes that are active for water oxidation, with a turnover number of 3200. They also reported that some mononuclear ruthenium polypyridyl complexes are active for the reaction, with good turnover numbers. Very recently, Bernhard et al. reported that ies of bis-phenylpyridine, bis-aquo iridium(III) complexes are robaserust enough to catalyze the oxidation of water to dioxygen efficiently. These results are interesting because mononuclear ruthenium complexes are believed to have much less catalytic activity for water oxidation.
