Preparation, proton conduction, and application in ammonia synthesis at atmospheric pressure of La0.9Ba0.1Ga1–xMgxO3–α

La0.9Ba0.1Ga1–xMgxO3–α (0 ≤ x ≤ 0.25) was prepared by the microemulsion method. A single phase of LaGaO3 perovskite structure was formed when x was ≥0.15. Electrochemical hydrogen permeation (hydrogen pumping) proved that La0.9Ba0.1Ga1–xMgxO3–α had proton conduction, and the proton conduction was measured by AC impedance spectroscopy method from 400 to 800 °C in hydrogen atmospheres. Among these samples, La0.9Ba0.1Ga0.8Mg0.2O3–α has the highest proton conductivity with the values of 9.51 × 10−4 to 4.68 × 10−2 S cm−1 at 400–800 °C. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in an electrolytic cell using La0.9Ba0.1Ga0.8Mg0.2O3–α as electrolyte. The rate of NH3 formation was 1.89 × 10−9 mol s−1 cm−2 at 520 °C upon imposing a current of 1 mA through the cell.