One more step for converting sunlight into chemical energy
Oeiras, 05.04.13
During photosynthesis, the energy from sunlight is used to oxidise water providing the electron source for the fixation of carbon dioxide into carbohydrates. Inspired by nature’s success, chemists seek to mimic this clever mechanism to convert and store solar energy into chemical energy by working on the water oxidation reaction, which in practice is equivalent to splitting water (H2O) in oxygen (O2) and hydrogen (H2). The critical challenge has been developing the right catalyst for the job. In the latest issue of Chemistry a European Journal, chemists from the Homogeneous Catalysis Lab and from the University of Girona in Spain present a new water oxidation catalyst with exceptional efficiency.
Water oxidation is one of the biggest scientific and technological challenges towards artificial photosynthesis. For decades, scientists have been trying to understand and imitate nature by creating new water oxidation catalysts but despite promising results with homogeneous catalysts, high activity and stability is often lacking.
The exceptional water oxidation catalyst developed in this work is an organometallic iridium complex with remarkable catalytic activity. The numbers themselves are impressive: in the presence of one molecule of this catalyst 40.000 water molecules are split before the catalyst deactivates. In the conditions tested (NaIO4 as oxidant in water at 40oC), this is the largest efficiency ever reported for a metal catalysed water oxidation reaction.
Original Article
Chem. Eur. J.. doi: 10.1002/chem.201204568
Highly Effective Water Oxidation Catalysis with Iridium Complexes through the Use of NaIO4
Zoel Codolà, João M. S. Cardoso, Beatriz Royo, Miquel Costas, Julio Lloret-Fillol
