Synthesis and properties of the materials in Ni/SrTi1-xCrxO3 system

Abstract

Synthesis of materials in Ni/SrTi1-xCrxO3 system was undertaken towards evaluation of the possibility of their application in SOFC technology. Materials with different chromium and nickel content were obtained. Single-phase SrTi1-xCrxO3 (x = 1, 4 and 6 mol. %) samples synthesized by modified citrated method were impregnated with nickel nitrate solution to achieve different Ni concentration (1, 5, 10 or 20 wt %). The proper thermal treatment resulted with formation of composites in NiO/doped-SrTiO3 system. The obtained materials were investigated for their structural, redox and electrical properties. X-ray diffraction analysis showed the presence of strontium titanate and nickel oxide in composite systems but for materials with the highest amount of chromium a small amount of strontium chromate was also detected. The redox abilities of NiO/SrTi1-xCrxO3 systems examined by TPR/TPOx measurements indicate that all materials have catalytic potential in reduction-oxidation reaction. Moreover these tests showed that nickel can be incorporated into the strontium titanate structure during TPOx cycles. The results of electrical properties measurements carried out in synthetic air and H2/Ar atmosphere indicate that nickel introduced into the materials does not affect the conductivity nor conduction mechanism. Thermal expansion coefficients for obtained composites are practically independent of the amount of chromium incorporated into the SrTiO3 structure but slightly change with amount of nickel introduced to the system.