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Lecture Irina Zvereva

Rooster

WanneerWaar
25 september 2012 FWN-Building 5115.0017, Nijenborgh 4, 9747 AG, Groningen
Speaker: Prof. Dr. Irina Zvereva
Affiliation: Saint-Petersburg State University, Russia
Title: Photocatalytic activity of layered perovskite-type oxides
Date: Tue Sep 25, 2012
Start: 11.00
Location: FWN-Building 5115.0017
Host: Thom Palstra
Telephone: +31 50 363 4419

Abstract

The presentation focuses on the structural design and catalytic properties of materials based on perovskite-type layered oxides. Photocatalytic properties are discussed in comparison with relative binary oxides and oxides with 3D perovskite structure . The reactions of photocatalytic degradation of dyes and water splitting are considered as example.

There was a much attention to the application of TiO2 as a catalyst in various photochemical processes (water splitting or decomposition of organic chemicals in wastewater).

In last decade one of the main directions of the searching of novel photocatalysts is the study of catalytic activity of perovskite-type layered oxides with 3d, 4d, 5d- and 4f-elements. The structure and electronic properties of layered phases should strongly influence on the electron-hole recombination process and the nature of interlayered space. Use of layered materials of complex cationic content is especially promissing because of the possibility of modifying the chemical composition as well as microstructure by means of ion-exchange or intercalation, which is useful for designing photocatalysts based on semiconducting metal oxide sheets.

The current report presents results of the development of the photocatalytic systems based on nanostructured cation-ordered layered oxides and investigation of their catalytic activity in the reactions of model organic water contaminants degradation and photocatalytic water splitting under the UV-light irradiation.

In our work we consider the wide range of oxides which belong to layered perovskite-type structures (Ruddlesden-Popper, Dion-Jacobson and Aurivillius phases with various thickness of perovskite slabs) on the base of our experimental data. A main attention will be devoted to series A2Ln2Ti3O10 and ALnTa 2 O7 (A= Li, Na, K, Rb, Cs) which exhibit a complete ordering of A+ and Ln3+ cations inside the rock salt layers owing to essential differences in charge. New data on band gap energy, quantitative characteristics of water intercalation in layered structure and ion-exchange reactions in the water medium are reported. On the base of these sets of data the link between structural particularities and catalytic activity will be discussed. Unexpected high photocatalytic activity of some members of the series under investigation can be clear from point of a prominent role of the water intercalation into the interlayer space of the crystal structure.

 

Laatst gewijzigd:22 oktober 2012 14:30