Tin oxide surfaces. Part 13.—A comparison of tin(IV) oxide, tin(IV) oxide–palladium oxide and tin(IV) oxide–silica: an infrared study of the adsorption of carbon dioxide

Abstract

The adsorption of carbon dioxide onto tin(IV) oxide, tin(IV) oxide–palladium oxide and tin(IV) oxide–silica heat-treated in the temperature range 320–703 K has been studied by infrared spectroscopy. The surface species formed depend on the pretreatment temperature of the oxide. Bicarbonate and unidentate carbonate are formed at low pretreatment temperatures on all three oxides, but the higher Brönsted acidity of tin(IV) oxide–silica allows more bicarbonate formation than the other two oxides. At pretreatment temperatures 473 K the major adsorption products are unidentate carbonate and bidentate carbonate, together with small amounts of ‘organic’ or bridging carbonate.