Structural and electrochemical properties of the perovskite oxide Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ

The perovskite oxide Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ was synthesised by a combustion method. Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ obtained at 1400 °C has been shown to have an orthorhombic structure with space group Pnma (62), a = 5.4388(1)Å, b = 7.6969(1)Å, c = 5.4584(1)Å, V = 228.50(1)Å3 according to X-ray diffraction. The material is redox stable and maintains its structure in a reducing atmosphere. After reducing in 5% H2 at 900 °C for 190 h, Pr0.7Sr0.3Cr0.9Ni0.1O3 − 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 Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ shows enhanced resistance to nickel reduction. The conductivities of this material in air and 5% H2 were 27.4 and 1.37 S/cm respectively at 900 °C. Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ exhibits semiconductor behaviour in both air and 5% H2. The anode polarisation resistance of Pr0.7Sr0.3Cr0.9Ni0.1O3 − δ reached 0.98 Ωcm2 at 900 °C in wet H2 but still not good enough as a good SOFC anode although it could be further improved by optimisation of microstructure.