THE ACTIVATION OF CARBON DIOXIDE AT A MAGNESIUM (1 00) SURFACE THE ROLE OF OXYGEN TRANSIENTS

X-ray photoelectron and high resolution electron energy loss spectroscopic (XPS-HREELS) studies have shown that the adsorption of carbon dioxide at Mg(100) surfaces at 80K is followed by a dissociative reaction leading to the formation of a metastable surface carbonate above 80K. The formation of a carbonate species is proposed to proceed through oxidation of C0 (g) by an active oxygen surface transient O formed by dissociation of dioxygen or dissociative chemisorption of carbon dioxide. The O(1s) data establish that oxidation and carbonate formation occur simultaneously suggesting that dissociative chemisorption involves the formation of an oxygen adatom which can either form oxide or react with C0 to form carbonate