Dynamical change in the crystal field around the V(IV) ion on TiO/sub 2/ (rutile) surface accompanied by the interaction with adsorbed oxygen molecules

Journal Article · Thu Oct 23 04:00:00 EDT 1986 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100280a056· OSTI ID:7225116

Kera, Y; Matsukaze, Y

A broad ESR spectrum with an unresolved hyperfine splitting (hfs) was observed in TiO/sub 2/ (rutile) deposited with vanadium oxide (V(IV)-TiO/sub 2/) at 77-298 K under vacuum. Upon the introduction of oxygen gas, a very sharp spectrum with eight hf lines (/sup 51/V nucleus, I = 7/2) appeared at 77 K. The sharp spectrum, however, broadened out with an increase in the temperature. The hfs disappeared completely at 145 K and at 298 K it changed to a broad spectrum. The change was reversible. A computer simulation for the broad and sharp spectra was satisfactorily carried out by using the following parameters: g/sub perpendicular/ = 1.983, g/sub parallel/ = 1.950, A/sub perpendicular/ = 55 G, A/sub parallel/ = 173.1 G, and the line width (d) = 35 G; and g/sub perpendicular/ = 1.931, 1.922, g/sub parallel/ = 1.972, A/sub perpendicular/ = 46, 47 G, A/sub parallel/ = 152.2 G, and d = 7 G, respectively. The broad spectrum was assigned to the V(IV) ion that replaced the Ti ion site on the surface, the crystal field symmetry of which was ascribed to a distorted square pyramid, and the sharp spectrum was assigned to the V(IV) ion placed in a field of octahedral symmetry. Based on these results, it is suggested that the crystal field around the V(IV) ion changes dynamically from the distorted square pyramid to the octahedral symmetry accompanied by oxygen molecule adsorption. Part of an electron on the V(IV) ion evidently transferred to the oxygen molecule through some interaction. Similar ESR changes were also found in the cases of N/sub 2/O and NO gas adsorptions on V(IV)-TiO/sub 2/.

• Research Organization: Kinki Univ., Osaka, Japan
• OSTI ID: 7225116
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:22; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CRYSTAL FIELD
DATA
ELECTRON SPIN RESONANCE
ELEMENTS
EXPERIMENTAL DATA
HYPERFINE STRUCTURE
INFORMATION
IONS
LOW TEMPERATURE
MAGNETIC RESONANCE
MEDIUM TEMPERATURE
METALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
RESONANCE
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM