Kriventsov V, Kochubey D, Navio J A, Hidalgo M C, Colón G, Tsodikov M, Maksimov Y, Suzdalev I
Boreskov Institute of Catalysis, Novosibirsk, Russia.
J Synchrotron Radiat. 2001 Mar 1;8(Pt 2):528-30. doi: 10.1107/s0909049501000875.
The local Zr and Fe arrangements in the nanocomposite system Fe(x)/ZrO2 (x=0-0.2) obtained by sol-gel method were studied by EXAFS. The phase composition was found to vary significantly on iron loading. For the samples calcined at 500 or 600 degrees C, at x< or =0.01, the formed ZrO2 is a mixture of monoclinic and tetragonal structures. Only tetragonal structure is revealed at x > or = 0.05 with the exception of Fe0.2/ZrO2, calcined at 500 degrees C, where new non-typically short Zr-Zr distances (3.29, 3.43A) were observed. At low iron loading (less than one monolayer) Fe3+ ions were found to localize within the pre-surface layers of ZrO2 nanoparticles showing property of isolated ions. For greater Fe loading, iron exhibits either two-dimensional layer structure or two-phase system.
