Comparison of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _3-δ perovskite synthesis methods and their effect on the particle size

The dense structure required by mixed-ionic and electronic conducting (MIEC) membrane based on La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _3-δ (LSCF) material could be influenced by the particle size of the LSCF, as this densification involves sintering of the particles. The particle size could be determined by using an appropriate synthesis method. The aim of this work is to investigate the effect of synthesis method to the particle size of the resulted powders. In this work, LSCF was successfully synthesized by sol-gel, co-precipitation, and solid-state methods. The coprecipitation is carried out with and without aging treatment after addition of precipitating agent. All LSCFs have a structure similar to the LaCoO3 structure as mother compound. Solid-state and co-precipitation with aging treatment can produce LSCF with high purity. Meanwhile, there were still other phases in LSCFs which were synthesized by sol-gel and co-precipitation methods without aging treatment. Other phases that appear are estimated from the Co ₃ O ₄ for co-precipitation method without aging treatment and Co ₃ O ₄ and Fe ₂ O ₃ for sol-gel method. The solid-state method is capable of producing particles with the highest crystallinity compared to other methods. The TGA results from LSCF with the sol-gel method and co-precipitation (without and with aging time) showed that the perovskite could be formed at temperature 650 °C. Characterization of LSCF particles with Scanning Electron Microscope (SEM) showed that all samples had irregular particle shapes, with uniformly small particle for sol-gel method, and the possibility of formation of large particle for co-precipitation method. However, Particle Size Analysis (PSA) analysis shows that in general, the co-precipitation method could produce smaller particle (particle size 1904.1 nm) than the solid-state method (particle size 2812.4 nm).