Mechanism of adsorption and desorption of CO on SrO(001) surface

The desorption behaviors of (CO)-O-18 on the particle surface of SrO (001) were investigated by the method of Temperature Programmed Desorption (TPD). The mechanism responsible for desorption process and the relationship between adsorption and desorption were discussed. (CO)-O-16 formed due to the exchange of oxygen isotopes and escaped from the surface of SrO particles during heating the particles pretreated with the absorption of (CO)-O-18 gas. A small amount of (CO)-O-18 also desorbed from the particle surface and the activation energy of (CO)-O-18 desorption was approximate to that of (CO)-O-16 desorption. With the increasing of the exposure amount of (CO)-O-18 gas, the desorption amount of (CO)-O-16 was increased and the peak desorption temperature was decreased. However, the desorption amount of (CO)-O-16 tended to become constant when the surface coverage of (CO)-O-18 gas was higher than a certain value.