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On the morphological properties of tungsta-titania de-NOxing catalysts

Published online by Cambridge University Press:  31 January 2011

C. Cristiani ,
M. Bellotto ,
P. Forzatti  and
F. Bregani
C. Cristiani
Affiliation:
Dipartimento di Chimica Industriale e Ingegneria Chimica del Politecnico, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
M. Bellotto
Affiliation:
CISE, P.O. Box 12081, 20134 Milano, Italy
P. Forzatti
Affiliation:
Dipartimento di Chimica Industriale e Ingegneria Chimica del Politecnico, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
F. Bregani
Affiliation:
ENEL-CRTN, Via Monfalcone 15, 20100 Milano, Italy
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Abstract

Tungsta-titania samples with different W loadings up to 15 wt.% and calcined at different temperatures have been prepared and characterized by surface area measurements, mercury porosimetry, x-ray diffraction, microstructural analysis, and laser Raman spectroscopy. It has been found that W inhibits the initial sintering of TiO2 (anatase) and the anatase → rutile transformation. The morphological and structural properties of the samples (surface area, porosity, and phase composition) have been related to the microscopic properties of the materials such as crystallite dimensions and defects concentration. A model for the sintering of TiO2 is discussed. This model is based on the diffusion of surface hydroxyls, formed upon adsorption of water on surface oxygen vacancies. A role for W is proposed in terms of stabilization of both material defects and surface hydroxyls.

Type
Articles
Information
Journal of Materials Research , Volume 8 , Issue 8 , August 1993 , pp. 2019 - 2025
Copyright
Copyright © Materials Research Society 1993

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