The precursor powders of BaCe1-xDyxO3-alpha (x=0.05, 0.10, 0.15, 0.20) ceramics were prepared via a microemulsion process. Dense ceramic samples were obtained by heat-treating the precursor powders under lower calcining and sintering temperatures than those of traditional high-temperature solid-state reaction. X-ray diffraction and scanning electron microscope observation were carried out to examine the structures and morphologies of the ceramic samples. Proton conduction behaviors at intermediate temperature were studied by the techniques of AC impedance spectroscopy. hydrogen concentration cell and isotope effect. Ammonia was synthesized successfully at atmospheric pressure in an electrolytic cell using BaCe0.85Dy0.15O3-alpha as an electrolyte. (C) 2010 Elsevier B.V. All rights reserved.