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Adsorption of Ag, O2 and N2O on AG/RH(100)

1981; Elsevier BV; Volume: 111; Issue: 2 Linguagem: Inglês

10.1016/0039-6028(80)90704-9

1879-2758

Wayne Daniel, Y. Kim, H.C. Peebles, John White,

Copper-based nanomaterials and applications

The adsorption of Ag on Rh(100) at 300 K is characterized by uniform growth of at least the first two monolayers. The desorption is characterized by two distinct peaks. The lower temperature state shows zero order kinetics and a desorption energy of 65.9 ± 0.6 kcal mole−1 while the high temperature state shows first order behavior. The activation energy is slightly coverage dependent. Our data do not allow a unique description but a pre-exponential factor of 8.9 × 1012s−1 and an activation energy of 66.0−1.5θ Ag kcal mole−1 is quite satisfactory. AES analysis can be used to establish the Ag coverage over the first monolayer. The initial dissociative sticking coefficient for O2 is 0.8 at 530 and 680 K on clean Rh(100) while that for N2O drops from 0.48 to 0.21 over this same interval. The saturation O(KVV) signal from O2 is twice that observed for N2O. The LEED patterns at saturation are c(2 × 2) and p(2 × 2) for O2 and N2O respectively. Simple site blocking models adequately describe the influence of Ag on O2 and N2O chemisorption.