A perovskite electrochemical systemwas developed for selective NOx reduction of diesel engine exhaust. The systemwas composed of a La0.9Sr0.1CoO3 +/-delta oxidation catalyst and a (La0.85Sr0.15)(0.95)MnO3 +/-delta/Ce0.9Gd0.1O1.95 electrochemical cell with BaO nanopariticles. A selectivity of 25-35% was achieved with a NOx conversion of 65-75% in 1000 ppm NO with 8% O-2 at 375 degrees C. The superior performance of the system was suggested to be ascribed to the promotion in NO2 formation substantially activating the NOx trapping and reduction processes on the electrode. (C) The Author(s) 2018. Published by ECS.