Investigations on the local structure and g factors for the interstitial Ti3+ in TiO2

Abstract

The EPR g factors g i (i = x, y, z) for the interstitial Ti 3+ in rutile are theoretically studied from the perturbation formulas of these parameters for a 3d 1 ion in rhombically compressed octahedra. The ligand octahedron in the impurity center is found to be less compressed than that on the host interstitial site due to the Jahn-Teller effect. The local compression parameter (≈0.026) and the rhombic distortion angle δφ (≈0.7 • ) around the impurity Ti 3+ are smaller than the host values (≈0.091 and 3.5 • ). The theoretical g factors based on the above local structural parameters are in good agreement with the experimental data. In addition, the g factors for a tetragonal interstitial Ti 3+ center are also reasonably interpreted.

Influence of gamma-irradiation on the photocatalytic activity of Degussa P25 TiO2

“…center in TiO 2 can arise from an interstitial Ti 4? capturing one electron in a reducing atmosphere [40] or under gamma irradiation of TiO 2 [15]. UV-VIS and ESR measurements [36] confirm that irradiation causes generation of oxygen vacancies and associated Ti 3?…”

Analysis on the local structures for 3d1 impurities (Ti3+ and V4+) in KTiPO4

“…However, V 4+ doped into KTP can occupy both tetravalent Ti 4+ sites and form centres C 2 and C 3 , respectively. The property of g z < ( g x + g y )/2 < 2 for the observed g factors of all the centres reveals the lowest 2 B 1 (ζ) (|d xy ⟩) state for orthorhombically compressed octahedral 3d 1 clusters …”

“…These properties and behaviors are strongly concerned with the local environments (e.g., occupation, lattice distortions due to the Jahn–Teller effect and size and charge mismatch), which can be efficiently probed by means of the electron paramagnetic resonance (EPR) measurements. Particularly, 3d 1 (Ti 3+ , V 4+ ) ions can be regarded as a typical system in EPR studies in view of the Jahn–Teller effect and the relatively simpler energy level structure (e.g., at most five levels under orthorhombic symmetry) as compared to other TM ions . EPR experiments have been employed for KTP doped with Ti 3+ and V 4+, and the orthorhombic spin Hamiltonian parameters (SHPs) were measured for one Ti 3+ centre C 1 and two V 4+ centres C 2 and C 3 with the same properties of g z < g y < g x < 2 and |A x | < |A y | < |A z |.…”

CaF2-Based Near-Infrared Photocatalyst Using the Multifunctional CaTiO3 Precursors as the Calcium Source

“…There are many ESR signals included in CCaTiO3, such as O2 3-(g = 2.0317), 15 ionic superoxide anion O2 -(g = 2.0267), 16 •O2 -(g = 2.0063), 17 and single electron oxygen vacancy Vo • (g = 2.0038, 1.9868, and 1.9820). [18][19][20][21] The…”

“…ESR signals of C-ETYCT locate at g = 2.0020 and 1.9721, which correspond to Vo • and Ti 3+ , [19][20][21] respectively. C-ETYCC and C-ETYCCT mainly possess the Vo • signal at g = 2.0020.…”