Solid State Ionics | 2019
Influence of strontium content on the oxygen surface exchange kinetics and oxygen diffusion in La1–xSrxCoO3–δ oxides
Abstract
Abstract Oxygen surface exchange kinetics between the gas phase oxygen and La1–xSrxCoO3–δ (x\u202f=\u202f0, 0.3, 0.4, 0.6) oxides at 0.67\u202fkPa oxygen pressure in the 600–850°°С range were investigated. The mechanism within the two-step model including two consecutive stages, oxygen dissociative adsorption and oxygen adatom incorporation into the oxide lattice, was analysed. The oxygen diffusion coefficient (D), the rate of heterogeneous oxygen exchange (rH) and the elementary rates of this process — dissociative adsorption (ra) and incorporation (ri) — were determined. The effect of oxygen vacancy concentration, strontium segregation on the surface, temperature and oxygen pressure on rH, ra and ri are discussed.