Dual exsolution in silver‐functionalized layered and cubic perovskite oxides

Abstract

Listen

Translate article

AbstractIn this work, exsolution is achieved from both the A‐site and B‐site of (BaGd0.8La0.2)1‐xAgxCo2O6‐δ and (BaLa)1‐xAgxCoFeO6‐δ (x = 0.04, 0.1, and 0.2) perovskites prepared via solid‐state sintering. Through synchrotron radiation powder X‐ray diffraction and X‐ray absorption spectroscopy techniques, the chemical composition of the nanoparticles was determined to constitute both Ag and CoO. Microstructural studies were done using scanning electron microscopy with varying sizes and shapes of nanoparticles present for respective annealing atmospheres and temperatures. By applying a numerical model to experimental data, it was also established that the changes in enthalpy for oxygen vacancy formation decrease with an increase in silver dopant. From thermogravimetric measurements, the single (BaLa)0.95Ag0.10CoFeO6‐δ perovskite had relatively higher water uptake than the layered (BaGd0.8La0.2)0.95Ag0.10Co2O6‐δ perovskite. The total electrical conductivity done in dry and wet conditions decreased with an increase in temperature in the range of 300–800°C for both layered and single perovskites. The results obtained from electrical conductivity relaxation measurements of (BaGd0.8La0.2)0.95Ag0.10Co2O6‐δ with nanoparticles exhibit increased oxygen reduction reaction activity than (BaLa)0.95Ag0.10CoFeO6‐δ with nanoparticles.