A FOURIER-TRANSFORM INFRARED STUDY OF CO2 AND CO2 H-2 INTERACTIONS WITH CESIUM-DOPED COPPER-CATALYSTS/

FTIR spectra are reported of CO2 and CO2/H-2 on a silica-supported cae sium-doped copper catalyst. Adsorption of CO2 on a ''caesium''/silica surface resulted in the formation of CO2- and complexed CO species. Ex posure of CO2 to a caesium-doped reduced copper catalyst produced not only these species but also two forms of adsorbed carboxylate giving b ands at 1550, 1510, 1365 and 1345 cm(-1). Reaction of carboxylate spec ies with hydrogen at 388 K gave formate species on copper and caesium oxide in addition to methoxy groups associated with caesium oxide. Met hoxy species were not detected on undoped copper catalyst suggesting t hat caesium may be a promoter for the methanol synthesis reaction. Met hanol decomposition on a caesium-doped copper catalyst produced a smal l number of formate species on copper and caesium oxide. Methoxy group s on caesium oxide decomposed to CO and H-2, and subsequent reaction b etween CO and adsorbed oxygen resulted in carboxylate formation. Metho xy species located at interfacial sites appeared to exhibit unusual ad sorption properties.