Dense ceramic samples BaCe0.9-xZrxSm0.10O3-α (x=0.10, 0.15, 0.20, 0.30) were obtained by heat-treating the precursors prepared from a coprecipitation route. The phase structure, chemical stability and conduction behaviors of the ceramic samples have been investigated by X-ray powder diffraction and alternating current impedance spectroscopy methods. All the ceramic samples displayed a single phase of orthorhombic perovskite. The samples with x ≥0.20 were relatively stable after exposed to the flowing mixed gases: CO2 (φ=3%)+H2O (φ=3%)+N2 (φ=94%) at 873 K for 12 h. Among the samples tested, the sample with x=0.20 exhibited both adequate conductivity and better chemical stability. The contribution of different charged species for x=0.20 sample to the conduction in wet hydrogen atmosphere was investigated by means of gas concentration cells. It was found that the sample of x=0.20 was almost a pure ionic conductor, and the ionic conduction was contributed mainly by proton and partially by oxide ion in wet hydrogen atmosphere at 773-1073 K. The ammonia synthesis at atmospheric pressure in an electrolytic cell based on the sample of x=0.20 was successfully conducted and the peak ammonia formation rate achieved 2.67 × 10-9 mol·s- 1·cm-2 with direct current of 0.80 mA at 773 K.
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