XAS technique was used to study changes around Cu atom in the C~Ai204-A203 system, induced by composition variations. The results showed that for compositions with 30 and 43% of CuO, the Cu atoms presents the same surroundmg of Cu in the CuO oxide (Ncu-0=4, Rcu-0=1.96 A). Samples with 20% (doped or undoped) showed siNcative changes in the Cu nearest neighbors number (Ncu-0=3) and in the mean bond length @cu-(r-1.93A). The qualitative analysis of the edge region showed that for the 20% of CuO

more »

... ple, some Cu atoms changes fiom C U +~ to Cufl. This change was more pronounced for the CuO 20% tmdoped sample.