THE OXIDATION OF CO ON THE PT(100)-(5X20) SURFACE Academic Article uri icon

abstract

  • The kinetics of the CO oxidation reaction were examined on the Pt(100)-(5 20) surface under UHV conditions. The transient isothermal rate of CO2 production was examined both for exposure of an oxygen-dosed surface to a beam of CO and for exposure of a CO-dosed surface to a beam of O2. Langmuir-Hinshelwood kinetics were found to apply in both cases. For the reaction of CO with preadsorbed oxygen atoms, the reaction rate was dependent upon the square-root of the oxygen atom coverage, suggesting that oxygen atoms were adsorbed in islands on this surface. The oxidation of preadsorbed CO was observed only when the initial CO concentrations were less than 0.5 monolayer (c(2 2) structure), suggesting that the dissociative adsorption of oxygen required adjacent four-fold surface sites. The activation energy calculated for the reaction of CO with preadsorbed oxygen was 31.4 kcal/mol. This value was 30 kcal/mol greater than the activation energy measured for the reaction of O2 with preadsorbed CO. Strong attractive interactions within the oxygen islands were at least partially responsible for this difference. The reaction kinetics in both cases changed dramatically below 300 K; this change is believed to be due to phase separation at the lower temperature. 1981.

published proceedings

  • SURFACE SCIENCE

author list (cited authors)

  • BARTEAU, M. A., KO, E. I., & MADIX, R. J.

citation count

  • 69

complete list of authors

  • BARTEAU, MA||KO, EI||MADIX, RJ

publication date

  • March 1981