High catalytic activity of heteropolynuclear cyanide complexes containing cobalt and platinum ions: Visible-light driven water oxidation

A near-stoichiometric amount of O₂ was evolved as observed in the visible-light irradiation of an aqueous buffer (pH 8) containing [Ru^II(2,2'-bipyridine)₃] as a photosensitizer, Na₂S₂O₈ as a sacrificial electron acceptor, and a heteropolynuclear cyanide complex as a water-oxidation catalyst. The heteropolynuclear cyanide complexes exhibited higher catalytic activity than a polynuclear cyanide complex containing only Co^III or Pt^IV ions as C-bound metal ions. The origin of the synergistic effect between Co and Pt ions is discussed in relation to electronic and local atomic structures of the complexes. A platinum assist: A near-stoichiometric amount of O₂ was evolved as observed in the visible-light irradiation of an aqueous buffer (pH 8) containing [Ru^II(2,2'-bipyridine)₃] as a photosensitizer, Na₂S₂O₈ as a sacrificial electron acceptor, and a heteropolynuclear cyanide complex as a water-oxidation catalyst. The synergistic effect between the Co and Pt ions was confirmed to facilitate the water-oxidation catalysis by the heteropolynuclear complex.