Impregnated nanoparticles are very effective in improving the electrochemical performance of solid oxide fuel cell (SOFC) anodes possibly due to the extension of reaction sites and/or the enhancement of catalytic activity. In this work, samaria-doped ceria (SDC), pure ceria, samaria, and alumina oxides impregnated Ni-based anodes are fabricated to compare the site extending and the catalytic effects. Except for alumina, the impregnation of the other three nano-sized oxides could substantially enhance the performance of the anodes for the hydrogen oxidation reactions. Moreover, single cells with CeO(2) and Sm(2)O(3) impregnated anodes could exhibit as great performance as those with SDC impregnated anodes. When the impregnation loading reached the optimal value, 1.7 mmol cm(-3), these cells exhibit very high performance, with peak power densities around 750 mW cm(-2). The high performance of CeO(2) and Sm(2)O(3) impregnated anodes demonstrates that the improved performance are mainly attributed to the significantly improved electrochemical activities of the anodes, but not to the extension of triple-phase-boundary, and wet impregnation is indeed an alternative and effective technique to introduce these nano-sized catalytic active oxides into the anode configuration of SOFCs to enhance cell performance, stability and reliability. (C) 2011 Elsevier B.V. All rights reserved.