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The structural changes of the supported vanadium oxide in the V2O5/TiO2(anatase) EUROCAT EL10V8 powder catalyst during reduction and oxidation at 420 and 490 °C were studied with in-situ X-ray absorption spectroscopy (XAS). The Vanadium K-edge XAS results are compared with pure bulk V2O5. For the reduction–oxidation cycle at 420 °C, similar structural changes as for bulk V2O5 were observed for the supported vanadium oxide: a reduction to the VO2 structure and re-oxidation back to V2O5. After reduction at 490 °C however, a different structure was obtained: very regular “VO6” octahedra with a V2.8+ valence. This may point to a structural support effect. [ABSTRACT FROM AUTHOR]

Abstract: The thermal reduction of thin vanadium oxide layers (8 and 16Å) deposited with magnetron sputtering on mineral anatase TiO2(001) was examined with ultraviolet photoelectron spectroscopy (UPS). Completely oxidized vanadium oxide layers were deposited. During heating, the vanadium oxide layers reduced and evaporated, the thinnest vanadium oxide layer (8Å) even vanished. A re-oxidation of the heated 16Å V2O5/TiO2 could not restore the reduced vanadium oxide completely to V5+. [Copyright &y& Elsevier]