2002 Volume 110 Issue 1284 Pages 722-726
The microstructure and chemical changes in the composite working electrode of electrochemical cells ((Composite working electrode)|Pt(Cathode)|YSZ|Pt(Anode)) for NO decomposition were observed and investigated. It was found that the NiO/YSZ interface is not stable at the electrochemical cell operating temperature of 600°C. Structure evolution was studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The formation of a small amount of Ni phase and of small size NiO grains with a size of about 10-100 nm in the NiO/YSZ interface region was observed and investigated. The reduction of NiO into Ni phase in the near surface region under the external voltage applied between the cathode and anode is proposed. The oxidation of small Ni grains into NiO grains as a result of NO and O2 gas adsorption at the NiO/YSZ interface is discussed.
