Fe K-Edge X-ray Absorption Fine Structure Determination of γ-Al2 O3 -Supported Iron-Oxide Species.
The structure of FeOx species supported on γ-Al2 O3 was investigated by using Fe K-edge X-ray absorption fine structure (XAFS) and X-ray diffraction (XRD) measurements. The samples were prepared through the impregnation of iron nitrate on Al2 O3 and co-gelation of aluminum and iron sulfates. The dependence of the XRD patterns on Fe loading revealed the formation of α-Fe2 O3 particles at an Fe loading of above 10 wt %, whereas the formation of iron-oxide crystals was not observed at Fe loadings of less than 9.0 wt %. The Fe K-edge XAFS was characterized by a clear pre-edge peak, which indicated that the FeO coordination structure deviates from central symmetry and that the degree of FeOFe bond formation is significantly lower than that in bulk samples at low Fe loading (<9.0 wt %). Fe K-edge extended XAFS oscillations of the samples with low Fe loadings were explained by assuming an isolated iron-oxide monomer on the γ-Al2 O3 surface.
Materials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560 (Japan).
Atsuko
A
Tomita
Materials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560 (Japan).
Takeshi
T
Miki
Research and Development Department, Mizusawa Industrial Chemicals Ltd. 1-1 Mizusawa, Tainai 959-2638 (Japan).
Takeru
T
Tango
Research and Development Department, Mizusawa Industrial Chemicals Ltd. 1-1 Mizusawa, Tainai 959-2638 (Japan).
Tatsuro
T
Murakami
Research and Development Department, Mizusawa Industrial Chemicals Ltd. 1-1 Mizusawa, Tainai 959-2638 (Japan).
Hideyuki
H
Nakagawa
Materials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560 (Japan). tai.y@aist.go.jp.
Yutaka
Y
Tai
X-ray absorption spectroscopy; aluminum oxide; iron oxide; nanostructures; supported catalysts