Silver-modified La0.6Ca0.4CoO3 (Ag-LCCO)catalyst for molecular oxygen reduction reaction(ORR)were prepared by an electroless deposition process using N2H4 as the reducing agent at room temperature.The LCCO catalyst was modified with silver content that varied from 0.3 to 30 wt.% without damaging the LCCO microstructure,which was used as binary electrocatalyst for the ORR.The electrochemical behavior of the different silver loading LCCO catalysts were studied on classical bilayered gas diffusion electrodes(GDEs),of which the active layer composed of 55wt.% carbon black,25wt.%Ag-LCCO(catalyst) and 20wt.% PTFE as binder,produced by ultrasonic.The electrocatalytic properties for the ORR were evaluated by polarization curves and electrochemical impedance spectroscopy(EIS) in an alkaline electrolyte.Both the Ag loading and firing temperatures were found to have a significant impact on the electrode performance,which could facilitate or block the electrochemical processes of the air cathodes,processes that include oxygen adsorption,charge-transfer and oxygen electrochemical reduction.The electrocatalytic activity of the binary catalyst electrodes is improved dramatically by Ag –LCCO catalyst electrodes,even at very low Ag loading.Furthermore,at an optimal Ag loading of 3.0wt.% and firing temperature of 800 ,the current density of 200mA/cm2(at-0.4V vs.Hg/HgO) was achieved for a Ag-LCCO cathode.Additionally,these electrodes showed an improved performance compared to electrodes only made of carbon black and LCCO.