La0.6Sr0.4CoxFe1-xO3-delta (LSCF). La0.6Sr0.4Cu0.2Fe0.8O3-delta, Ba(0.5)Sr0.4Co(0.8)Fe(0.2)O(3-delta) and LaFeO3-delta nanoparticles were synthesized by a reverse micelle procedure. Controlling the size of the micelles through the water:oil phase ratio enabled synthesis of phase pure perovskite particles with average sizes from 14 nm to 50 nm. Small amounts of an impurity phase, likely cobalt oxide, were detected in the XRD spectrum of high cobalt content samples of LSCF (x = 0.8). La0.6Sr0.4Co0.2Fe0.8O3-delta nanoparticles were utilized to coat the surface of a dense thin-film La0.6Sr0.4Co0.2Fe0.8O3-delta solid oxide fuel cell cathode. The polarization resistance of the nanoparticle coated electrode, measured at open circuit in air at 973 K, was 20% lower than an equivalent un-coated electrode. (C) 2011 Published by Elsevier B.V.