X-Ray photoelectron study of the reaction of water with cerium

The interaction of D₂ O with a polycrystalline cerium surface, successfully cleaned by heavy Ar⁺ bombardment and annealing, was studied at 120 were observed at BE 530.3 (Ce₂O₃) and 532.7eV (adsorbed OD). When clean Ce at 120 K was exposed to D₂ O, the O(1s) spectra were initial eV (adsorbed D₂ O). For exposures greater than 10 Langmuir (L), a multilayer of ice grows and the O(1s) spectra become dominated by a peak at 5The results of interaction with D₂ O are compared with oxidation by O₂. The significant differences are: (1) the absence of Ce(IV) when oxidati relatively small extent of oxidation that occurs when Ce is exposed to D₂ O at 120 K, and (3) the larger chemical-shift of the Ce(III)-derived specThe XPS studies of the interaction of D₂ O with Ce reported here may be summarized as follows:(1) Exposure at 300 K gives rise to O(1s) features characteristic of oxide and hydroxide, while the Ce(3d) spectra indicate Ce(III), but no CE((2) Exposure at 120 K gives O(1s) features characteristic of adsorbed OD, chemisorbed D₂ O, a multilayer of ice, and a small amount of oxide. T are characteristic of clean Ce except for slight broadening.(3) Exposure at 120 K followed by warming to 240 and 300 K gives spectra characteristic of hydroxide and oxide surface-species. Between 240 and 300 K, O(1s) intensity.(4) At 300 K, a relatively thick layer of oxide forms, and after an exposure of 50 L the features characteristic of metallic Ce are no longer observabl(5) As compared to the case for O₂, exposure to D₂ O gives rise to different satellite-splittings in the Ce(3d) spectra, suggesting that di formed in the two cases.(6) The spectra observed for Ce exposed to D₂ O are in excellent accord with those found for the heavier lanthanides 4].