Structural and electrical transport properties of Pr-doped SrTi 0.93 Co 0.07 O 3-δ a novel SOEC fuel electrode materials

Abstract

Solid Oxide Electrolyzer Cells (SOECs) are very promising electrochemical devices for the production of syngas (H 2 /CO) by H 2 O and CO 2 co-electrolysis. The structure, microstructure and electrical properties of the fuel electrode material play a crucial role in the performance of the whole cell and efficiency of electrocatalytic reduction of steam into hydrogen. In the present work, a novel Co and Pr co-doped SrTiO 3-δ material attracted attention as a potential fuel electrode for SOFC/SOEC. Materials with different praseodymium content were prepared by a solid-state reaction process. XRD confirmed cubic perovskite structure in all obtained samples. SEM results showed porosity in doped materials and EDX proved ABO 3 stoichiometry. TEC values were about 1.17–1.26•10 −5  K −1 very close to the YSZ electrolyte value. XPS studies turn out that a praseodymium can be multivalent and exist on mixed +3 and + 4 oxidation state. Electrical conductivity of samples was measured by DC 4-wire method in range of 100-800 °C. Highest value of total conductivity was achieved for Sr 0.7 Pr 0.3 Ti 0.93 Co 0.07 O 3-δ and reached 23.7 S∙cm −1 . The obtained results were discussed and analyzed in term of defect chemistry.