Reduction kinetics of zeolite-hosted mono- and polynuclear titanium oxide species followed by UV/vis diffuse reflectance spectroscopy: influence of location and coordination
Article Abstract:
The kinetics of the reduction of zeolite-hosted mononuclear Ti(VI)Ox species followed by ultraviolet/vis diffuse reflection spectroscopy were investigated. Results showed that the reduction kinetics can be fitted if a Ti site exists at the surface of the zeolite NaY crystals and two sites in the void structure. The reduction rates for various Ti(VI)Ox species were found to increase with an increase in the excitation energy of the O to Ti charge transfer and decreases with an increase in the nuclearity of TiO clusters.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Probing different kinds of vanadium species in the VSi-beta zeolite by diffuse reflectance UV-visible and photoluminescence spectroscopies
Article Abstract:
A study was conducted to analyze different types of vanadium species in the VSi-beta zeolite. Diffuse reflectance ultraviolet-visible and photoluminescence spectra were utilized to carry out the analyses. The samples exhibited photoluminescence spectra with maxima at around 500 nm with a vibrational fine structure. Results indicated that photoluminescence spectroscopy can generate accurate data on the symmetry of vanadium sites.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Influence of citric acid treatment on the surface acid properties of zeolite beta
Article Abstract:
It has been possible to develop a method of boosting the amount of acid sites, particularly Bronsted acid sites, on the surface of H-beta zeolite. For disproportionation and transalkylation of toluene and C9 aromatics, the catalytic activity of zeolite beta treated by citric acid is greater than that of zeolite beta untreated.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 2000
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