UV Resonance Raman Spectroscopic Identification of Titanium Atoms in the Framework of TS-1 Zeolite

Abstract

Framework titanium atoms in titanium-substituted silicalite (TS-1) can be identified by UV resonance Raman spectroscopy since the associated Raman bands at 1125, 530, and 490 cm(-1) (see figure) are observed only when the charge transfer transition associated with the framework Ti atoms is excited by a UV laser. Thus, framework Ti atoms can be distinguished from nonframework Ti atoms and other defect sites. This method can be applicable to identifying transition metal atoms in the frameworks of other molecular sieves.

Epoxidation of Linear Olefins over Stacked TS-1 Zeolite Catalysts

“…Figure 4 shows the UV Raman spectra of NSTS-1(MW), TS-1(MW), and TS-1(HT) with excitation by the 325 nm line, which is close in energy to the charge transfer band of TS-1 at 220 nm. The resonance-enhanced Raman bands at 475, 530, 1,129 cm -1 were attributed to titanium species onto tetrahedral coordinated framework [28]. The bands at 475 and 530 cm -1 were attributed to the bending and symmetric stretching vibrations of Ti-O-Si species respectively, and the band at 1,125 cm -1 was assigned to the asymmetric stretching vibration of the framework Ti-O-Si.…”

Effects of VO x /AlMCM-41 Surface Structure on Ethylbenzene Oxydehydrogenation in the Presence of CO2

“…However, V 2 O 5 diffraction peak appeared in samples with vanadium loading above 1.5 mmol/g. UV-Raman spectroscopy was a powerful technique to identify the structure of isolated transition metal anchored on the surface of metal oxide [17,18]. As shown in Fig.…”

Metathesis of butene to propene on WO3 supported on MTS-9 titanium-silica: effect of loading on selectivity of product and yield of propene

“…MTS-9 and SiO 2 have common bands at *488, *790, *976, and *1,090 cm -1 , but the intensity of the band at *1,090 cm -1 for MTS-9 is stronger than that for SiO 2 , suggesting that these bands (*976 and *1,090 cm -1 ) can be attributed to the resonance Raman effect [22]; the others bands were characteristic of SiO 2 . For catalysts with different WO 3 loadings, very strong bands at *1,000 and *1,110 cm -1 are observed.…”