Abstract: Fluorite-type rare earth complex oxides of (Ce_0.8La_0.2)_1－xCa_xO_2－δwere prepared by a sol-gel process. Crystalstructure and microstructure of the product were characterized by X-ray diffraction (XRD), transmisson electronmicroscopy (TEM) and scanning electron microscopy (SEM). Electrical conductivity measurements performed in N₂/H₂ over the temperature range of 400 to 800 ℃ showed that conductivity was enhanced by extrinsic doping. Ammonia was synthesized from nitrogen and hydrogen under atmospheric pressure in a solid state proton conducting cell reactor, and the optimal temperature determined in the ammonia production was 650 ℃. The effect of non-Faradaic electrochemical modification of catalytic activity (NEMCA) explained the effect of imposed potential on the rate of NH3 synthesis. The rates of evolution of ammonia were 7.2×10^－9 mol•s^-1•cm^-2 and 7.5×10^－9 mol•s^-1•cm^-2 for Ce_0.8La_0.2O_2－δ and (Ce_0.8La_0.2)_0.975Ca_0.025O_2－δrespectively at 650 ℃.

Key words: Sol-gel, Fluorite-type structure, Proton conductor, Ammonia synthesis