The oxygen state active in the catalytic oxidation of carbon monoxide at a caesium surface: Isolation of the reactive anionic CO2 delta- species

Analysis of X-ray photoelectron spectra taken as a function of oxygen exposure shows that at a caesium surface at 80 K the O-delta- state develops first as a precursor to the oxide O2- and peroxo O-2(delta-) states; the O-delta- species are reactive to CO(g) at 80 K giving the anionic form of adsorbed carbon dioxide CO2delta-; the latter is readily converted to surface carbonate on exposure to dioxygen.