%0 Journal Article
%T Effect of Sintering Temperature on Microstructure, Chemical Stability, and Electrical Properties of Transition Metal or Yb-Doped BaZr0.1Ce0.7Y0.1M0.1O3£¿¦Ä (M£¿=£¿Fe, Ni, Co, and Yb)
%A Behzad Mirfakhraei
%A Farshid Ramezanipour
%A Venkataraman Thangadurai
%J Frontiers in Energy Research
%D 2014
%I Frontiers Media
%R 10.3389/fenrg.2014.00009
%X Perovskite-type BaZr0.1Ce0.7Y0.1M0.1O3£¿¦Ä (M = Fe, Ni, Co, and Yb) (BZCY-M) oxides were synthesized using the conventional solid-state reaction method at 1350¨C1550¡ãC in air in order to investigate the effect of dopants on sintering, crystal structure, chemical stability under CO2 and H2S, and electrical transport properties. The formation of the single-phase perovskite-type structure with an orthorhombic space group Imam was confirmed by Rietveld refinement using powder X-ray diffraction for the Fe, Co, Ni, and Yb-doped samples. The BZCY-Co and BZCY-Ni oxides show a total electrical conductivity of 0.01 and 8 ¡Á 10£¿3 S cm£¿1 at 600¡ãC in wet H2 with an activation energy of 0.36 and 0.41 eV, respectively. Scanning electron microscope and energy-dispersive X-ray analysis revealed Ba and Co-rich secondary phase at the grain-boundaries, which may explain the enhancement in the total conductivity of the BZCY-Co. However, ex-solution of Ni at higher sintering temperatures, especially at 1550¡ãC, decreases the total conductivity of the BZCY-Ni material. The Co and Ni dopants act as a sintering aid and form dense pellets at a lower sintering temperature of 1250¡ãC. The Fe, Co, and Ni-doped BZCY-M samples synthesized at 1350¡ãC show stability in 30 ppm H2S/H2 at 800¡ãC, and increasing the firing temperature to 1550¡ãC, enhanced the chemical stability in CO2/N2 (1:2) at 25¨C900¡ãC. The BZCY-Co and BZCY-Ni compounds with high conductivity in wet H2 could be considered as possible anodes for intermediate temperature solid oxide fuel cells.
%K high temperature proton conductor
%K chemical stability
%K doped barium cerate
%K SOFC
%K anode material
%U http://www.frontiersin.org/Journal/10.3389/fenrg.2014.00009/abstract