Improve the catalytic property of La_0.6Sr_0.4Co_0.2Fe_0.8O₃/Ce_0.9Gd_0.1O₂ (LSCF/CGO) cathodes with CuO nanoparticles infiltration

LSCF/CGO composite cathodes decorated with small amount (less than 1 wt%) of nano CuO particles has been synthesized by infiltration technique. The area specific resistance (ASR) of the LSCF/CGO at 500 °C has been significantly reduced by the CuO infiltration from 15.5 Ω cm² and 0.62 Ω cm² to 3.9 Ω cm² and 0.32 Ω cm² at 500 °C and 650 °C respectively. The redox reaction of Cu²⁺/Cu¹⁺ at the interface of CuO and LSCF/CGO has been assigned as the main reason for the improvement. Lattice parameter change of LSCF at 500 °C has been detected by High Temperature XRD, indicating partial diffusion of Cu²⁺ into the lattice of LSCF, and formation of a new Cu containing compound. The performance stability of the infiltrated samples has been investigated by aging at 500 °C and 650 °C for 150 hours in stagnant air. A slight degradation of the catalytic property was observed during the aging process. The degradation may be attributed to three factors: (i) the coarsening of CuO nanoparticles, (ii) segregation of the SrO due the lattice change and (iii) instability of the new Cu²⁺ contained compounds.