A kinetic study on the low temperature oxidation of CO over Ag-contaminated Au fine powder

The mechanism of CO oxidation with O2 on Ag-contaminated Au fine powder (Ag/Au) was studied by kinetic measurements combined with the determination of the amount of CO2 produced. The kinetic behavior of “Ag/Au having the steady state surfaces” indicated that the oxidation proceeds through co-adsorption of CO and O2 to form (CO3)∗ succeeded by its decomposition enhanced by the interaction with CO and O2 to produce CO2 at the contact interface between surface silver and gold support. The kinetics measurements performed on “Ag/Au having the oxidized surfaces” indicated that only the reduction of reactive adsorbed oxygen with CO in the reaction mixture to produce CO2 proceeds at first without incorporation of O2 in the gas phase and that the participation of O2 in the CO2 production process as well as its incorporation into the catalyst surface starts gradually as the reduction of reactive adsorbed oxygen on Ag proceeds.