Structural and electrochemical properties of the perovskite oxide Pr_0.7Sr_0.3Cr_0.9Ni_0.1O_{3- δ}

The perovskite oxide Pr0.7Sr0.3Cr0.9Ni0.1O3-delta was synthesised by a corribustion method. Pr0.7Sr0.3Cr0.9Ni0.1O3-delta obtained at 1400 degrees C has been shown to have an orthorhombic structure with space group Pnma (62), a=5.4388(1)angstrom, b=7.6969(1)angstrom, c=5.4584(1)angstrom, V=228.50(1)angstrom(3) according to X-ray diffraction. The material is redox stable and maintains its structure in a reducing atmosphere. After reducing in 5% H-2 at 900 degrees C for 190 h, Pr0.7Sr0.3Cr0.9Ni0.1O3-delta Still exhibits an orthorhombic structure. A lattice volume expansion of 0.61% was observed during the reduction, which may be attributed to reduction of Pr, Cr and Ni ions accompanying loss of lattice oxygen. TGA analysis and EDS indicate Pr0.7Sr0.3Cr0.9Ni0.1O3-delta shows enhanced resistance to nickel reduction. The conductivities of this material in air and 5% H-2 were 27.4 and 1.37 S/cm respectively at 900 degrees C. Pr0.7Sr0.3Cr0.9Ni0.1O3-delta exhibits semiconductor behaviour in both air and 5% H-2. The anode polarisation resistance of Pr0.7Sr0.3Cr0.9Ni0.1O3-delta reached 0.98 Omega cm(2) at 900 degrees C in wet H-2 but still not good enough as a good SOFC anode although it could be further improved by optimisation of microstructure. (C) 2008 Elsevier B.V. All rights reserved.