Doped ceria-Ca3(PO4)2-K3PO4 composite electrolyte:: Proton conductivity at intermediate temperature and application in atmospheric pressure ammonia synthesis

A precursor of Ce0.8Y0.2O1.9 (YDC) solid electrolyte was synthesized by the gol-gel method. YDC and phosphates powders were prepared by mixing the YDC and phosphates according to different weight ratios. The mixtures of the YDC and binary phosphates were ground and sintered at 1400 degrees C. The proton conductivity in solid electrolyte of the sintered samples was examined using electrochemical methods at 400 similar to 800 degrees C. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in the solid state proton conducting cell reactor. The optimal condition for the ammonia production was determined. The result indicated that composite electrolyte of 80wt% YDC: 20wt% binary phosphates as proton conductor could obtain the highest ionic conductivity and ammonia production rate among the four samples, the rate of evolution of ammonia was up to 9.5 x 10(-9) mol center dot s(-1) center dot cm(-2).