Vanadium-titanium oxides with a V coverage ≤1.6 of the theor. monolayer (bidimensional sheet of V oxide on the TiO2 surface), prepd. by wet impregnation, grafting, and exchange techniques, were studied by x-ray diffraction, ESR, IR, UV-near-IR diffuse reflectance, and chem. anal. of the valence state and of the total amt. of V present, before and after washing with a basic soln. Results indicate that 3 V-oxide surface structures can be formed. At the lower coverages, V reacts with surface OH groups of TiO2, forming strongly interacting and stabilized V(IV) ions, part of which are coordinatively unsatd. This species is present also at higher coverages together with a 2nd V oxide species, interpreted as a bidimensional cluster of V(V) ions weakly interacting with the TiO2 surface. The V oxide in excess of a monolayer is present as multilayer cryst. V2O5. The nature of the V oxide monolayer is discussed in relation to the presence of these species and to IR anal. of the 1st overtone of ν(V:O), which suggests the presence of V ions with a single oxo group and a higher frequency of ν(V:O) as compared to the bulk V2O5. The shift to lower frequencies found by other authors is probably related to the presence of adsorbed H2O. [on SciFinder(R)]

Chemical and spectroscopic study of the nature of vanadium-oxide monolayer supported on a high-surface-area TiO2 anatase

CENTI, Gabriele;
1986-01-01

Abstract

Vanadium-titanium oxides with a V coverage ≤1.6 of the theor. monolayer (bidimensional sheet of V oxide on the TiO2 surface), prepd. by wet impregnation, grafting, and exchange techniques, were studied by x-ray diffraction, ESR, IR, UV-near-IR diffuse reflectance, and chem. anal. of the valence state and of the total amt. of V present, before and after washing with a basic soln. Results indicate that 3 V-oxide surface structures can be formed. At the lower coverages, V reacts with surface OH groups of TiO2, forming strongly interacting and stabilized V(IV) ions, part of which are coordinatively unsatd. This species is present also at higher coverages together with a 2nd V oxide species, interpreted as a bidimensional cluster of V(V) ions weakly interacting with the TiO2 surface. The V oxide in excess of a monolayer is present as multilayer cryst. V2O5. The nature of the V oxide monolayer is discussed in relation to the presence of these species and to IR anal. of the 1st overtone of ν(V:O), which suggests the presence of V ions with a single oxo group and a higher frequency of ν(V:O) as compared to the bulk V2O5. The shift to lower frequencies found by other authors is probably related to the presence of adsorbed H2O. [on SciFinder(R)]
1986
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1906900
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 184
  • ???jsp.display-item.citation.isi??? 196
social impact