The effect of calcination atmosphere on structural properties of Y-doped SrTiO3 perovskite anode for SOFC prepared by solid-state reaction

Abstract

Abstract Recently Y-doped SrTiO3 (YST) perovskite has been reported as a promising alternative for Ni/YSZ cermets as anode material for solid oxide fuel cells due to its mixed, ionic and electronic conduction. In this work SrTiO3 was synthesized by solid-state reaction method, calcined, and sinterized to obtain undoped (ST), 4% (YST04) and 8% (YST08) of Y-dopant and as a heterojunction with yttria-stabilized zirconia (YST08/YSZ). The effects of calcination atmosphere and dopant concentration on formation of the perovskite and grain size distribution of the material were investigated. It was observed that calcination under Ar/5%H2 atmosphere have increased the dopant maximum concentration in the SrTiO3 cubic crystal structure when compared to inert atmosphere. When the Y solubility limit was exceeded, a pyrochlore phase Y2Ti2O7 was formed at the intergranular region due to the deficiency of oxygen vacancies, especially in the presence of inert atmosphere. TGA and DTA curves present a peak of water desorption and two overlapping peaks of SrCO3 phase change and decomposition. Ceramic microstructure was studied by SEM-EDS and the results showed that Y incorporation inhibits the grain growth in sintering step; reaching a smallest amount value of grain size in YST08/YSZ heterojunction under Ar/5%H2 atmosphere.