CO dissociation on K-modified Cu(112) and Cu(117)

Using valence band photoelectron spectroscopy it is demonstrated that CO di ssociates on the potassium-modified stepped copper surfaces, Cu(1 1 2) and Cu(1 1 7). The dissociation process is conditioned by both the presence of steps and an alkali metal coverage above a certain threshold value. Carbona te is formed at 375 K via the process CO + CO --> CO2 + C and reaction with oxygen. Further heating to 600 K results in decomposition of the carbonate . The threshold alkali metal coverage for dissociation of CO on stepped cop per surfaces depends on the step density. It is found that the height of th e Fermi edge in the valence band photoelectron spectra is correlated with t he CO uptake for a given potassium coverage and the perturbation and dissoc iation of the CO molecule with increasing temperature. (C) 2001 Elsevier Sc ience B.V. All rights reserved.