La0.5Ba0.5MnO3 nanocubes and nanoparticles were synthesized by hydrothermal and co-precipitation methods, respectively. The catalytic performances and thermal stabilities of the samples in the oxidation of CO and CH4 were evaluated. La0.5Ba0.5MnO3 nanocubes showed much higher catalytic activity and thermal stability in CO and CH4 oxidation compared with the nanoparticles. After running at 560 degrees C for 50 h under the reaction conditions in CH4 oxidation, the surface area of the nanoparticles decreased significantly, while the nanocubes well maintained their surface area. Jahn-Teller effect had a significant influence on the catalytic performances of La0.5Ba0.5MnO3 nanocubes and nanoparticles. The much higher catalytic activity and thermal stability of La0.5Ba0.5MnO3 nanocubes were mainly predominated by the perfect single crystal structure. (C) 2010 Elsevier B.V. All rights reserved.