ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Vanadium oxides supported on MgF2 with rutile structure, obtained by impregnation and precipitation-deposition, were investigated. XPS, ESR, IR and XRD studies revealed that the surface of MgF2 is partially covered by non-acidic OH groups, which persist after loading with vanadium oxides. In impregnated samples, the surface fraction of vanadium is linearly dependent on loading. In precipitated-deposited samples, the surface fraction of vanadium remains constant because of the increase of surface area due to peptization of MgF2 aggregates. At a low concentration of vanadate solution, (V=O)F5-type surface complexes are formed. At higher concentrations, isolated VO4 tetrahedra appear at the surface, which undergo polymerization to form chains of tetrahedra or trigonal bipyramids. These may condense further into islands of the monolayer of polyvanadate species, with the σπ-bonded terminal oxygen sticking out perpendicular to the surface.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740151202
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