화학공학소재연구정보센터
Journal of Catalysis, Vol.153, No.1, 158-164, 1995
The Effect of Subsurface Oxygen on the Desorption-Kinetics of Propylene from Ag(110)
The effect of subsurface oxygen on the desorption of pi-bonded propylene from Ag(110) was studied using temperature programmed desorption and x-ray photoelectron spectroscopy. The kinetic parameters for propylene desorption from Ag(110) without subsurface oxygen were compared to those for propylene desorption from Ag(110) when the subsurface region was saturated with oxygen. In the limit of zero coverage the activation energy and preexponential factor for propylene desorption from Ag(110) with subsurface oxygen is equal to the activation energy and preexponential fatter for propylene desorption from Ag(110) without subsurface oxygen (E(0) = 12.7 +/- 0.6 kcal/mol, nu = 1.2 x 10(16) s(-1)). On both Ag(110) surfaces, with and without subsurface oxygen, the activation energy for desorption decreases as the propylene coverage increases indicative of weak repulsive interactions. The difference in the lateral interaction energy for propylene on the two surfaces is within the experimental uncertainty. Subsurface oxygen apparently does not affect the kinetic parameters even for the desorption of a weakly pi-bound species from Ag(110), even though surface oxygen is known to strengthen such bonds.