EXAFS study of niobium sites in nanocrystalline Nb-doped SnO2 oxide ceramics

The niobium environment of nanocrystalline SnO2 matrixes prepared by the classical ceramic route and a sol-gel process was studied. Structural investigation was performed on 2% mol of Nb2O5-doped SnO2 samples by using EXAFS measurements at the Nb and Sn K edges. The formation of a non-homogeneous substitutional solid solution was observed. The homogeneity of the solid solution was improved by the sol-gel process and by increasing the firing temperature.