Preparation of platinum and palladium films by MOCVD and their electrochemical properties

Platinum and palladium films with various compositions and structures were prepared by metal organic chemical vapour deposition (MOCVD) by controlling the deposition conditions. The films were deposited as electrodes on zirconia solid electrolyte and their electrochemical properties were examined by impedance spectroscopy. Carbon containing (Pt-C and Pd-C) films consisted of agglomerated fine particles (2-5 nm in diameter) and exhibited higher electrode conductivities than conventional Pt paste electrodes at temperatures below 873 K. However, sintering of the fine particles and/or oxidation of impurity carbon or Pd spoil the electrochemical performance. On the other hand, two phase Pt-ZrO₂ films show promise as electrode materials for zirconia electrolyte at low temperatures because of their higher conductivity than Pt paste electrodes (below 973 K) and their thermal stability.