Palladium-impregnated or infiltrated La0.8Sr0.2MnO3-Gd0.2Ce0.8O1.9 (LSM-GDC) composites are studied as the oxygen electrodes (anodes) for the hydrogen production in solid oxide electrolysis cells (SOECs). The incorporation of small amount of Pd nanoparticles leads to a substantial increase in the electrocatalytic activity and stability of the LSM-GDC oxygen electrodes. The electrode polarization resistance (R-E) at 800 degrees C on a 0.2 mg cm(-2) Pd-infiltrated LSM-GDC electrode is 0.13 Omega cm(2), significantly smaller than 0.42 Omega cm(2) for the reaction on the pure LSM-GDC electrodes. The overpotential loss is also substantially reduced after the Pd infiltration; at an anodic overpotential 50 mV and 800 degrees C, the current increases from 0.15 A cm(-2) for the pure LSM-GDC anode to 0.47 A cm(-2) on a 0.3 mg cm(-2) Pd-infiltrated LSM-GDC. The infiltrated Pd nanoparticles enhance the stability of the LSM-GDC oxygen electrodes and are most effective in the promotion of the diffusion, exchange and combination processes of oxygen species on the surface of LSM-GDC particles, leading to the increase in the oxygen evolution reaction rate. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.