Cobalt-oxo core of a water-oxidizing catalyst film

J Am Chem Soc. 2009 May 27;131(20):6936-7. doi: 10.1021/ja902121f.


In photosynthesis, water is oxidized at a protein-bound Mn(4)Ca complex. Artificial water-oxidation catalysts that are similarly efficient and based on inexpensive and abundant materials are of great interest. Recently, assembly of a catalyst as an amorphous layer on inert cathodes by electrodeposition starting from an aqueous solution of cobalt ions and potassium phosphate has been reported. X-ray absorption spectroscopy on the cobalt catalyst film (CoCF) suggests that its central structural unit is a cluster of interconnected complete or incomplete Co(III)-oxo cubanes. Potassium ligation to Co-bridging oxygens could result in Co(3)K(mu-O)(4) cubanes, in analogy to the Mn(3)Ca(mu-O)(4) cubane motif proposed for the photosynthetic Mn complex. The similarities in function and oxidative self-assembly of CoCF and the catalytic Mn complex in photosynthesis are striking. Our study establishes a close analogy also with respect to the metal-oxo core of the catalyst.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cobalt / chemistry*
  • Electrochemical Techniques / methods
  • Fourier Analysis
  • Models, Molecular
  • Oxidation-Reduction
  • Oxides / chemistry
  • Photosystem II Protein Complex / chemistry
  • Spectrometry, X-Ray Emission / methods
  • Water / chemistry*


  • Oxides
  • Photosystem II Protein Complex
  • Water
  • Cobalt
  • cobalt oxide