Characterization of the synthesis and reactivity behavior of nanostructured vanadia model catalysts using XPS and vibrational spectroscopy

SURFACE SCIENCE

卷:600

Article; Proceedings Paper

Hess, Christian

关键词: supported vanadium oxide;    vanadia;    SBA-15;    methanol oxidation;    spectroscopy;    XPS;    Raman;   

DOI  :  10.1016/j.susc.2005.11.063

来源: Elsevier

【 摘 要 】

Nanostructured vanadia model catalysts, i.e., highly dispersed vanadium oxide supported on mesoporous silica SBA-15 (VOx/SBA15), were prepared. The mechanism for the synthesis of VOx/SBA-15 was elucidated by detailed characterization of the individual synthesis steps using XPS and vibrational spectroscopy. The resulting surface vanadium oxide species (0-2.3 V/nm(2)), grafted on the inner pores of the SBA-15 silica matrix, consists of tetrahedrally coordinated vanadia as inferred from UV-VIS- and Raman spectroscopy. The prepared vanadia model catalysts were tested in the partial oxidation of methanol to formaldehyde yielding high formaldehyde selectivities of 94% at 350 degrees C. XPS and Raman analysis of the catalyst after reaction reveal the presence of methoxy as well as a significant amount of carbonaceous species on the surface. Our results demonstrate that a detailed understanding of partial oxidation reactions requires the combination of complementary spectroscopic techniques ultimately within one experimental set-up. (c) 2006 Elsevier B.V. All rights reserved.

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