J. Phys. IV France 7 (1997) C2-891-C2-892
Low and High-Temperature In Situ X-Ray Absorption Study of the Local Order in Orthorhombic α-MoO3 Upon Hydrogen ReductionA. Kuzmin1, J. Purans1, Ph. Parent2 and H. Dexpert2
1 Institute of Solid State Physics, Kengaraga 8, LV-1063 Riga, Latvia
2 LURE, Université Paris-Sud, Bât. 209D, 91405 Orsay cedex, France
In-situ x-ray absorption spectroscopy has been applied to the study of the modifications of the short range order in orthorhombic α-MoO3 under low and high-temperature hydrogen reduction. It was obsewed that at low-temperature (T ≈ 110°C) reduction, a formation of molybdenum bronzes HxMoO3 (x ≤ 2) occurs while at high-temperature (T ≥ 400°C) reduction, α-MoO3 transforms into MoO2. Both processes have great applied importance since they are related to electrochromic and catalytic properties of α-MoO3. The information on the local atomic and electronic structure, obtained from the Mo K-edge XAFS and XANES analyses, allowed us to follow all steps of the reduction process and to formulate a mechanism of hydrogen interaction with the layered-type structure of α-MoO3.
© EDP Sciences 1997