Structure sensitivity of the dynamics of CO oxidation on Pd(111), Pd(110) and polycrystalline Pd surfaces: Infrared chemiluminescence study of the product CO2

The infrared chemiluminescence technique has been applied to the catalytic oxidation of CO on Pd(111), Pd(110) and polycrystalline Pd surfaces. The product CO2 molecules were vibrationally and rotationally excited in all cases. However, the vibrational energy states of CO2 were different among these three surfaces. This result means that the structure of the activated CO2 complex (i.e., the dynamics of CO oxidation) depends on the surface structures. In addition, the steady-state reaction rates of CO oxidation as a function of surface temperature were also different among the Pd surfaces. These results show that the CO oxidation on Pd is structure-sensitive not only in the kinetics but also in the dynamics.