Oxidation of carbon monoxide and deuterium on a Pd(100) film

For Pd/MgO(100) pre-exposed to oxygen, the catalytic oxidation of CO and D- 2, respectively, has been studied in the temperature range 100-300(degrees) C. At temperatures greater than or equal to 200(degrees)C, the CO2 desorpti on rate is independent of oxygen coverage, theta(O), and the reactive stick ing coefficient for CO is close to unity. The D2O desorption rate is strong ly dependent on theta(O). D-2 adsorption is blocked by adsorbed oxygen and the maximum D2O desorption rate is reached when almost all oxygen has been consumed (theta(O)< 0.03). The formation of an oxygen c(2x 2) structure, co existing with the initial p(2x 2) phase, is reflected in the oxidation rate s.