Oxygen activation on microcrystalline Bi2O3

The interaction of dioxygen with polycrystalline Bi2O3 is studied by means of X-ray Photoelectron, IR and EPR spectroscopies. The formation of superoxide species on the surface is demonstrated, after oxygen adsorption, by the presence of a weak O1s peak at 535.1 eV, by IR bands at about 1100 cm-1, both ascribed to adsorbed O2-, and it may be associated to the formation of EPR active paramagnetic centres associated to bismuth defects.