Preparation and characterization of ceria under an oxidizing atmosphere. Thermal analysis, XPS, and EPR study

Cerium hydroxide samples prepared with different precipitating agents (NaOH, KOH, NH[sub 4]OH) have been studied by thermogravimetry, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The untreated samples are a mixture of CeO[sub 2] and Ce(OH)[sub 4] with a small quantity of Ce(OH)[sub 3] present in the bulk of the solid. A part of the Ce[sup 3+] species remains stable even after calcination at high temperatures (1073 K) under air. The residual alkali elements issuing from the precipitating agents induce variations on the final state of the solid. 38 refs., 7 figs., 1 tab.