Low-temperature synthesis of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ perovskite powder via asymmetric sol-gel process and catalytic auto-combustion

La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ powder was synthesized by a combined EDTA-citrate complexing process via low-temperature auto-combustion synthesis with NH₄NO₃ as an oxidizer and a combustion trigger. Two novel methods were explored to improve this auto-combustion technology with reduced NH₄NO₃ addition: the use of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ as the combustion catalyst and the application of asymmetric sol-gel process to provide the precursor with different NH₄NO₃ concentrations. The prepared perovskite powder was characterized by BET, SEM, XRD and iodometric titration techniques. The catalytic performance of the powder was also examined in the decomposition of peroxide hydrogen. Experimental results indicate that powders from catalytic combustion and asymmetric precursor routes have more advantages in terms of better crystallites, higher specific surface area, higher B-site valence state, improved sintering capability and better catalytic performance in peroxide hydrogen decomposition than that from the synthesis with uniform NH₄NO₃ distribution.