Electronic Spectra of Ti(IV) in Zeolites: An Ab Initio Approach

Ettore Fois, Aldo Gamba, Gloria Tabacchi
  • ChemPhysChem, July 2005, Wiley
  • DOI: 10.1002/cphc.200500153

Electronic spectra of titanium sites in zeolites.

What is it about?

Interpreting real-lab experimental data is often a hard task, but computational models can provide some help. Here, for example, we calculated the electronic spectra of titanium-containing zeolites and found that a widespread criterion for interpreting these spectra was wrong. This has contributed to a better knowledge of these porous materials, which have large use in industry as mild oxidation catalysts.

Why is it important?

We have considered systems containing titanium sites with a tetrahedral geometry and we have calculated their electronic spectra. We have found that zeolites containing only one type of Ti sites give spectra with multiple bands. This occurs also for the simplest tetrahedral Ti species, the TiCl4 molecule. Hence, a spectrum with multiple bands is not an evidence of chemically different titanium sites in a Ti-zeolite. This result is important because it helps researchers to correctly interpret experimental data for a widespread class of industrial catalysts.

Perspectives

Gloria Tabacchi
university of insubria

We found that the established concept "one-band in the UV spectrum = one type of Ti site" was wrong. Moreover, the position of a band may be greatly influenced by the local Ti site geometry. These results have helped to understand electronic properties of titanium zeolites. This was one of the very first studies to do this, using a rigorous approach to study the electronic excitation.

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http://dx.doi.org/10.1002/cphc.200500153

The following have contributed to this page: Gloria Tabacchi