The reaction mechanism of CO oxidation to produce CO2 catalyzed by Cu2- in gas phase has been studied using density functional theory. By using the UB3LYP functional with the mixed basis sets level, the geometries of all spe-cies (reactants, intermediates, transition states, and products) were optimized, and the vibration frequencies as well as tests of wavefunction stability were also performed. The computational results indicate that the di-copper carbonate intermediate pathway is the easiest to occur. The most difficult pathway is that CO abstracts an oxygen atom from Cu2O2- to form product CO2. The catalytic activity of Cu2- toward CO oxidation reaction is better than that of Au2- and Ag2- .

Key words: Cu cluster anion, CO oxidation, mechanism, density functional theory