Structural and electrochemical properties of the perovskite oxide Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ
Abstract The perovskite oxide Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ was synthesised by a combustion method. Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ obtained at 1400 °C has been shown to have an orthorhombic structure with space group Pnma (62), a  = 5.4388(1)A, b  = 7.6969(1)A, c  = 5.4584(1)A, V  = 228.50(1)A 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 °C for 190 h, Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ 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 Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ 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 °C. Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ exhibits semiconductor behaviour in both air and 5% H 2 . The anode polarisation resistance of Pr 0.7 Sr 0.3 Cr 0.9 Ni 0.1 O 3 −  δ reached 0.98 Ωcm 2 at 900 °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.