Abstract
Thin compact La-Sr-Co-O composite films consisting of (La,Sr)CoO3-δ and (La,Sr)2CoO4+δ crystallites were prepared by compositional phase separation during pulsed laser deposition. While the total La:Sr ratio is kept constant at 70:30, different phase ratios and crystallite sizes are investigated. The effect of hetero-interfaces on the oxygen reduction reaction (ORR) kinetics was investigated by impedance spectroscopy. The enhancement relative to the appropriate reference activity is quantified in terms of the triple phase boundary (TPB) length specific activity k′TPB, resulting in k′TPB = 2–9·10−13 cm2/s at 600°C. A metastable Co-deficient perovskite phase La0.7Sr0.3Co0.9O3-δ formed in La-Sr-Co-O films under certain conditions was found to be highly active with an effective rate constant kq = 3·10−6 cm/s at 600°C, representing one possible source for the activity enhancement in these composite films.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
