Effects of Sr and Mn co-doping on microstructural evolution and electrical properties of LaAlO3

Abstract

In this work, we investigate the effects of Sr and Mn co-doping on the micro structural development and electrical properties of LaAlO3 synthesised by solid state reaction and sintered at 1500 and 1600 °C The addition of Sr and Mn contributed to the crystallization and stabilization of the perovskite structure. However, the addition of Sr alone lead to the formation of heterogeneous micro structure, while the combined effect of Sr and Mn improved Al and La homogeneity in the perovskite structure. Total electrical conductivity is enhanced by three orders of magnitude with Sr addition (La08Sr02AlO3-δ: 5.74 × 10-4 S/cm at 600 °C) and five orders of magnitude with Mn co-doping (La0.8Sr0.2Al0.8Mn0.2O3-δ: 3.6 × 10-2 S/cm at 600 °C) compared to the undoped LaAlO3 (2.96 × 10-6 S/cm at 600 °C). The Sr and Mn co-doped LaAlO3 present favourable catalytic activity for electrode reactions even with a low dopant concentration (20 mol%).