Samaria-doped ceria Ce0.8Sm0.2O2-δ(SDC) and SmFe0.7Cu0.3-xNixO3 have been synthesized by the sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM) and scanning electron microscopy(SEM).The electrochemical synthesis of ammonia was investigated at atmospheric pressure and low temperature,using the SFCN materials as the cathode,a Nafion membrane as the electrolyte,nickel-doped SDC(Ni-SDC) as the anode and silver-platinum paste as the current collector.Ammonia was synthesized from 25 to 100℃ when the SFCN materials were used as cathode,with SmFe0.7Cu0.1Ni0.2O3 giving the highest rates of ammonia formation.The maximum rate of evolution of ammonia was 1.13 × 10-8 mol·cm-2·s-1 at 80℃,and the current efficiency reached as high as 90.4%.
XU GaoChao,LIU RuiQuan & WANG Jin College of Chemistry and Chemical Engineering,Xinjiang University,Urumqi 830046,China
The SmBaCuMO5+δ (M=Fe, Co, Ni) (SBCM) powders were synthesized by the citrate sol-gel method and the powders were sintered to ceramic pellets. The powders and sintered ceramic pellets were characterized with XRD, TEM and SEM measurements. The cathode catalytic performances of SBCM ceramic pellets for ammonia synthesis were studied from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature, using SBCM ceramic pellets as cathode, Nafion proton exchange membrane as electrolyte, Ni-Ce0.8Sm0.2O2–δ(Ni-SDC) ceramic pellet as anode and silver-platinum as current collector. The results indicated that ammonia was synthe- sized from 25 to 95 oC, the yield of ammonia was up to 8.7×10–9 mol/(cm2·s) at 80 oC when SmBaCuNiO5+δ ceramic pellet was used as cathode.
