La2O3/BaCO3 nanocatalysts were synthesized from the coupling route of homogeneous precipitation with microemulsion under pulsed microwave heating. With the help of FTIR, TEM, and XRD, La2O3/BaCO3 nanocatalysts and their precursors were characterized. The performance of La2O3/BaCO3 nanocatalysts on the oxidative coupling of methane with carbon dioxide was compared with that of the La2O3/BaCO3 catalysts prepared by conventional homogeneous precipitation. Using La2O3/BaCO3 nanocatalysts, the reaction could take place at lower temperature, the conversion of methane was higher, but the carbon deposition on the catalysts was more serious, and the improvement of the selectivity Of C-2 was not distinct. (C) 2003 Elsevier B.V. All rights reserved.