title: Synthesis and morphology control of AM-6 nanofibers with tailored -V-O-V- intermediates.
abstract: Microporous vanadosilicates with octahedral VO6 and tetrahedral SiO4 units, better known as AM-6, have been hydrothermally synthesized with different morphologies by controlling the Na/K molar ratio of the initial gel mixtures. The morphology of the AM-6 materials changed from bulky cube to nanofiber aggregates as the Na/K molar ratio decreased from 1.9 to 0.2. Raman spectroscopy revealed that the VO3 (-) intermediate species plays an important role in the formation of the nanofiber morphology. The orientation of -V-O-V- chains in nanofiber aggregates was examined by confocal polarized micro-Raman spectroscopy. It was found that these aggregates are assemblies of short -V-O-V- chains perpendicular to the axis of nanofibers. The obtained AM-6 nanofibers greatly increase the exposed proportion of VO terminals, and thus improve the catalytic performance.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023 (P.R. China).
authors.forename: Meiling
authors.initials: M
authors.lastname: Guo
authors.forename: Zhaochi
authors.initials: Z
authors.lastname: Feng
authors.forename: Jan P
authors.initials: JP
authors.lastname: Hofmann
authors.forename: Bert M
authors.initials: BM
authors.lastname: Weckhuysen
authors.forename: Fengtao
authors.initials: F
authors.lastname: Fan
authors.forename: Can
authors.initials: C
authors.lastname: Li
keywords: Raman spectroscopy; X-ray diffraction; hydrothermal synthesis; reaction mechanisms; zeolites