An XPS,ISS and ESR Comparative Study of Eight-Coordination of Copper (II) Ions in the CuTho Compounds |
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| Authors: | R Bechara A Abou Kais M Guelton A D'huysser J Grimblot J P Bonnelle |
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| Institution: | Université des Sciences et Techniques de Lille Flandres-Artois Laboratoire de Catalyse Hétérogène et Homogène , URA CNRS 402 B[acaron]timent C3, 59655, Villeneuve D'Ascq Cedex |
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| Abstract: | In this study, we attempted to clarify the coordination state and the distribution of copper (II) ions in the CuThO compounds prepared by coprecipitation, by using several physico-chemical techniques in particular, X-Ray Photoelectron Spectroscopy (XPS). For atomic ratios Cu/Th ≤ 0.25, the copper (II) species are mainly located near the thoria surface. The Cu2p3/2 level shows a chemical shift towards the lower binding energy compared to Cu2+ ions in CuO and also a net decrease in the intensity of the satellite peak, characteristic of copper (11). A relation between these observations and the covalent character o f Cuzt- 02- bond i s esta- blished. Eightfold coordination of copper (11) i n the thoria lattice i s evident. These conclusions are in good agreement with Electron Spin Resonance (ESR) results. For a higher atomic ratio (Cu/Th > 0.25), a formation o f copper oxide crystallites i s observed on the thoria surface. |
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| Keywords: | XPS ISS ESR Copper Thorium Environment |
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