CO oxidation on a Cu(100) catalyst

The oxidation of carbon monoxide by molecular oxygen on a single crystal Cu(100) catalyst was studied at 458 K using reactant gas mixtures with CO/O₂ ratios of 2/1, 10/1 and 25/1 at a total pressure of 10 Torr. The catalytic activities were found to be strongly dependent upon the CO/O₂ ratio. Under stoichiometric reaction conditions (CO/O₂ = 2), the initial CO oxidation activity decreased sharply; with a highly reducing reaction mixture (CO/O₂ = 25), the initial activity gradually increased. These changes in catalytic activities with reactant gas mixture composition correlate with changes in surface composition, namely an increase in the surface oxygen coverage. Post-reaction TPD revealed the presence of a carbonate-like species which decomposed at ca. 630 K.