Preparation of noble metal (Ru, Ir)-carbon nano-composites by MOCVD as catalytic electrode for oxygen sensors

摘要

Ir-C and Ru-C nano-composite films containing about 50 vol% of carbon were prepared by MOCVD, and their microstructures and electrode properties were investigated. Ir or Ru particles of 5-20 nm in diameter were dispersed in amorphous C matrix. The AC conductivities associating to the interface charge transfer between Ir-C or Ru-C composite electrode and YSZ electrolyte were 100-1000 times higher than that of Pt electrodes. The emf values of the oxygen gas concentration cell constructed from the nano-composite electrodes and YSZ electrolyte showed the Nernstian theoretical values at low temperatures around 500 K. The response time of the concentration cell was 110 s at 550 K for Ir-C and 900 s at 500 K for Ru-C nano-composite electrodes.