Abstract
The interaction of CO with K and Cs doped Ru(10 1 0) has been studied by means of Auger electron spectroscopy (AES), thermal desorption (TD), electron energy loss spectroscopy (EELS), LEED and work function (WF) measurements. It was found that both alkali metals (AM) induce similar changes in the CO adsorption kinetics and energetics, with preferential filling of the promoted sites. The initial heat of CO adsorption, Δ H CO 0, associated with promoted CO ∗, increases linearly from 145 up to 224 kJ/mol with increasing alkali coverage, θ AM, the maximum Δ H CO 0 value being reached when coincident CO and AM desorption is detected. LEED and WF data for coadsorbate systems indicate formation of patches with different WF and compositions on the surface. EELS results show that the presence of AM causes an energy shift of the CO 2 π b → 2 π a transitions from 6.3 to ∼7.0 eV, removal of the AM ns valence transitions and plasmon excitations and appearance of new loss structures. Comparing the present data with the results on CO adsorption on Na doped Ru(10 1 0) the type and contribution of the possible direct COAM interactions are discussed.
Published Version
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