Preparation of iridium clusters by MOCVD and their electrochemical properties

Iridium-carbon (Ir-C) cluster films were prepared by metal organic chemical vapor deposition (MOCVD) using an acetylacetonate precursor. The Ir-C cluster films consist of Ir clusters (1 to 3 nm in diameter) and amorphous carbon layers which surround each Ir cluster. The Ir-C cluster films had excellent electrochemical performance as a reversible electrode for zirconia solid electrolyte particularly at low temperatures. The electrode/electrolyte interface conductivity of the Ir-C cluster films was about 100 times greater than that for other conventional platinum electrodes below 773 K. The emf values of the oxygen cell constructed from the Ir-C cluster film electrodes and zirconia electrolytes showed the Nernstian theoretical values even at 573 K.