A DRIFTS study of the interaction of alkali metal oxides with carbonaceous surfaces Original Research Article

An extensive DRIFTS study of the catalytic oxidation of carbon black by K2CO3, K2MoO4 and the nitrates of the alkali metals (Na, K, Rb and Cs), is described. The spectra of potassium benzoate, potassium phenoxide and catalytically oxidized fullerene C60 were recorded as model systems to enable the assignment of the various absorption bands. Alkali benzoate type species are likely to be formed upon decomposition of the alkali metal precursors in air, as well as alkali metal oxide species attached to the carbon surface. Absorption bands in the 1100–1150 cm−1 region and around 620 cm−1 are assigned to CO2, chemisorbed on these oxidic alkali metal clusters. A review of literature dealing with alkali-catalyzed carbon gasification is presented, to validate this assignment. A strong absorption band around 1140 cm−1 has been observed in the spectra of partially converted CaO/carbon black samples, which might also be related to chemisorbed CO2.