Ceramic porous cell stacks with electrodes made of La0.85Sr0.15CoxMn1-xO3-Ce0.9Gd0.1O1.95 (x=0, 0.01, 0.03, and 0.05) were analyzed using electrochemical impedance spectroscopy. Some of the cells were infiltrated with BaO and one was infiltrated with both BaO and La0.85Sr0.15MnO3. Most of the tests were performed in 10% O2 in Ar with or without 1000 ppm of NO between 250 and 500 °C. The polarization resistance was lower for the cell stacks infiltrated with BaO than for the backbone structure, indicating that the BaO nanoparticles increased the activity of the electrodes. Additional infiltration with La0.85Sr0.15MnO3 also decreased the resistance. Doping La0.85Sr0.15Mn1-yCoyO3+d (LSCoM) with Co affects the impedance spectra, increasing the resistance of the electrolyte as the Co doping level increases, possibly due to segregation of the Co to the triple phase boundary. In contrast, the resistances of the middle-and low-frequency arcs decrease with increasing Co content. Thus, the electrodes are more active at reducing NOx when 3 or 5% Co is doped into the B-site.
- Electrochemical cell
- NOx reduction