CO OXIDATION ON A CU(100) CATALYST

The oxidation of carbon monoxide by molecular oxygen on a single cryst al Cu(100) catalyst was studied at 458 K using reactant gas mixtures w ith 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), th e initial CO oxidation activity decreased sharply; with a highly reduc ing reaction mixture (CO/O2 = 25), the initial activity gradually incr eased. 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 th e presence of a carbonate-like species which decomposed at ca. 630 K.