Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (09): 967-970.doi: 10.3866/PKU.WHXB20050905

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Application of Proton Conductors (Ce0.8La0.2)1-xCaxO2-δ in Synthesis of Ammonia

LIU Rui-quan; XIE Ya-hong; LI Zhi-jie; WANG Ji-de; SUN Yi-gang   

  1. College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046
  • Received:2005-01-04 Revised:2005-02-23 Published:2005-09-15
  • Contact: WANG Ji-de

Abstract: Fluorite-type rare earth complex oxides of (Ce0.8La0.2)1-xCaxO2-δwere prepared by a sol-gel process. Crystalstructure and microstructure of the product were characterized by X-ray diffraction (XRD), transmisson electronmicroscopy (TEM) and scanning electron microscopy (SEM). Electrical conductivity measurements performed in N2/H2 over the temperature range of 400 to 800 ℃ showed that conductivity was enhanced by extrinsic doping. Ammonia was synthesized from nitrogen and hydrogen under atmospheric pressure in a solid state proton conducting cell reactor, and the optimal temperature determined in the ammonia production was 650 ℃. The effect of non-Faradaic electrochemical modification of catalytic activity (NEMCA) explained the effect of imposed potential on the rate of NH3 synthesis. The rates of evolution of ammonia were 7.2×10-9 mol•s-1•cm-2 and 7.5×10-9 mol•s-1•cm-2 for Ce0.8La0.2O2-δ and (Ce0.8La0.2)0.975Ca0.025O2-δrespectively at 650 ℃.

Key words: Sol-gel, Fluorite-type structure, Proton conductor, Ammonia synthesis