The operation of a solid oxide fuel cell (SOFC) based on BaCe0.8Y0.2O3-alpha (BCY20) at 800 degrees C was studied without using an anode material. A porous, Ce-rich phase with a fluorite structure was formed at a depth of approximately 10 mu m from the BCY20 surface by heat treatment at 1700 degrees C. This was due to the vaporization of BaO from the BCY20 surface. This treatment improved the cell performance and chemical stability to CO2 because the Ce-rich phase functioned as an electrically conducting and protective layer. The heat-treated BCY20 also had better chemical and redox stabilities over a Ni-Ce0.8Sm0.2O1.9 (SDC) cermet anode attached to the SDC electrolyte. The cell with the heat-treated BCY20 operated well on unhumidified methane, ethane, propane, and butane without carbon deposition, while the cell with the Ni-SDC cermet anode degraded within a few hours. Moreover, the BCY20 showed higher tolerance to 10 ppm H2S and stability over 20 times redox cycling in comparison to the Ni-SDC cermet anode. (c) 2006 Elsevier B.V. All rights reserved.