FTIR spectroscopic study of carbon dioxide adsorption/desorption on magnesia/calcium oxide catalysts

The nature of adsorption states of CO{sub 2} on mixed Mg/Ca oxide catalysts was investigated by FTIR spectroscopy. At room temperature, the unidentate is predominantly formed besides bicarbonate. On CaO-rich catalysts additional structures were detected and attributed to bridging carbonate and linearly adsorbed CO{sub 2}. Desorption behavior of these species is discussed in dependence on temperature. Surface basicity was quantitatively measured by the wavenumber difference of symmetric and asymmetric carbonate absorption bands and related to catalytic activity for oxidative coupling of methane. 22 refs., 6 figs., 2 tabs.