A novel ceramic system was prepared by adding Bi2O3 to gadolinia-doped ceria (GDC). This Bi2O3-GDC system was characterized by temperature-programmed and fixed-temperature reaction of methane in the absence of gas-phase oxygen. It was found that adding Bi2O3 to GDC can promote the catalytic activity for direct methane oxidation. A Bi2O3 loading of 25 wt% in the Bi2O3-GDC system maximized the activity of direct methane oxidation. Possible carbon deposition after the reaction can be negligible. In the temperature range of an intermediate-temperature solid oxide fuel cell (SOFC), pre-reduction promotes methane oxidation activity. At temperatures of about 600 degrees or lower, only CO2 and H2O are produced. However, CO and H-2 can be produced only at a temperature of about 700 degrees C or higher. This Bi2O3-GDC system can be applied to design SOFC anode materials for complete methane oxidation and thus full electricity generation, without syngas cogeneration, at low temperature. (C) 2007 Elsevier B.V. All rights reserved.