Protected Oxidation Catalyst | March 15, 2010 Issue - Vol. 88 Issue 11 | Chemical & Engineering News
Volume 88 Issue 11 | p. 48 | Concentrates
Issue Date: March 15, 2010

Protected Oxidation Catalyst

A homogeneous cobalt polyoxometalate catalyst splits water while avoiding oxygen-promoted degradation
Department: Science & Technology
Keywords: water oxidation catalyst, hydrogen fuel
Credit: Qiushi Yin
8811scicon_1cobalt
 
Credit: Qiushi Yin

A new catalyst that breaks water into its oxygen and hydrogen constituents avoids a problem that has plagued previous cobalt-based water-oxidation catalysts—the propensity of the released O2 to destroy the catalyst. Chemists have been avidly searching for photosynthetic mimics that catalyze the oxidation of water, with the goal of creating H2 to power fuel cells. The new catalyst, a bulky complex with the formula [Co4(H2O)2(PW9O34)2]10–, comes from the lab of Craig L. Hill at Emory University (Science, DOI:10.1126/science.1185372 ). Hill and coworkers say this complex is now the fastest known homogeneous water-oxidation catalyst and is an improvement over popular heterogeneous cobalt-based water-oxidation catalysts. Hill’s group surrounded the catalyst’s cobalt oxide core with bulky polytungstate ligands that resist oxidation. Not only is the catalyst free of carbon-based ligands, which are also vulnerable to oxidation, but it also self-assembles in boiling water. That the elements in the catalyst—cobalt, tungsten, phosphorus, and oxygen—are cheap and abundant is another plus. The researchers say their work prompts the examination of other polyoxometalate-stabilized multi-transition-metal oxide clusters as water-oxidation catalysts.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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