Promoting the Activity of Catalysts for the Oxidation of Water with Bridged Dinuclear Ruthenium Complexes

摘要

Water splitting is a promising way to supply sustainable fuel by producing hydrogen as an ideal energy carrier. Of the two half reactions, water oxidation and proton reduction coupled in water splitting, the oxidation of water is envisioned as the bottleneck of artificial photosynthesis. Although nature has solved this problem by employing the Mn4O5Ca cluster in the oxygen-evolving complex (OEC) of photo-system II as an efficient water oxidation catalyst, development of highly active synthetic analogs to the OEC remains a fundamental chemical challenge. Recently, extensive efforts devoted to molecular organometallic catalysts led to a rapid progress in this field. To date, the state-of-the-art molecular catalysts are those ruthenium and iridium complexes that show superior catalytic activity relative to those based on the first-row transition metals. However, the observed activities limited to thousands of turnover numbers (TONs) are insufficient to meet the criteria for application as a catalyst in water-splitting devices. In this regard, new catalysts with improved structural and catalytic properties are desired.