|A tetraruthenium polyoxometalate cluster (Ru blue, O red, Si yellow, W black) catalyzes the rapid oxidation of H2O to O2 in water at ambient temperature, and shows considerable stability under turnover conditions. Click to enlarge.|
A team of researchers from Forschungszentrum Jülich in Germany and Emory University in the US have synthesized a stable inorganic metal oxide cluster which catalyzes the fast and effective oxidation of water to oxygen. The work, a step toward artificial photosynthesis and the efficient production of hydrogen through solar energy, is published online in the journal Angewandte Chemie and is rated as a “very important paper”.
One of the barriers to achieving artificial photosynthesis is the formation of aggressive substances in the process of water oxidation. Plants solve this problem by constantly repairing and replacing their green catalysts. Artificial photosynthesis, however, depends on more stable catalysts.
To address this, the research team developed and synthesized a new inorganic metal oxide cluster with a core consisting of four ions of the rare transition metal ruthenium. This catalyzes the oxidation of water to oxygen while remaining stable itself.
Our water-soluble tetraruthenium complex displays its effects in aqueous solution already at ambient temperature. In contrast to other molecular catalysts for water oxidation, our catalyst does not contain any organic components. This is why it is so stable. Now the challenge is to integrate this ruthenium complex into photoactive systems, which convert solar energy into chemical energy.—Prof. Paul Kögerler from the Jülich Institute of Solid State Research
For this work, the energy for the process was obtained from a chemical oxidant. Prof. Kögerler synthesized and characterized the catalyst cluster together with his colleague Dr. Bogdan Botar. Catalytic measurements were carried out at Emory University.
Yurii V. Geletii, Bogdan Botar, Paul Kögerler, Daniel A. Hillesheim, Djamaladdin G. Musaev, and Craig L. Hill; An All-Inorganic, Stable, and Highly Active Tetraruthenium Homogeneous Catalyst for Water Oxidation; Angewandte Chemie, DOI: 10.1002/ange.200705652