Reducibility of vanadium oxide species in MCM-41

✍ Scribed by Gerd Grubert; Jirı́ Rathouský; Günter Schulz-Ekloff; Michael Wark; Arnošt Zukal

• Book ID: 104431465
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 225 KB
• Volume: 22
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(98)00088-2

✦ Synopsis

Vanadium-containing MCM-41 materials were prepared by (i) in situ incorporation of V during hydrothermal synthesis (denoted as V-MCM-41-syn), (ii) chemical vapour deposition of VOCl 3 on siliceous MCM-41 ( V-MCM-41-cvd ), and (iii) impregnation of siliceous MCM-41 with vanadyl acetylacetonate ( V-MCM-41-imp).
A well-ordered hexagonal structure of the materials is revealed from XRD patterns exhibiting four resolved reflections. The fraction of amorphous non-porous by-product obtained from nitrogen adsorption data increases in the sequence: V-MCM-41-imp#5%V-MCM-41-cvd#67%>V-MCM-41-syn#14%. The non-reducible species are assumed to be buried either in the amorphous by-product or inside the walls. Photoelectron spectroscopy reveals that the reducible vanadium oxide species are located in the channels of the MCM-41 structure. The analysis of the reduction kinetics points to a small fraction of polynuclear VV oxide reduced at a tenfold higher rate.