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Journal of Nanomaterials
Volume 2006, Article ID 17052, 9 pages

Fractal Dimension of Active-Site Models of Zeolite Catalysts

1Institut Universitari de Ciència Molecular, Universitat de València, Edifici d'Instituts de Paterna, P.O. Box 22085, València 46071, Spain
2Departamento de Química, Universidad Politécnica de Valencia, Camino de Vera s/n, València 46022, Spain
3Departamento de Ciencias Experimentales, Facultad de Ciencias Experimentales, Universidad Católica de Valencia San Vicente Mártir, Guillem de Castro 94, València 46003, Spain

Received 20 March 2006; Revised 31 May 2006; Accepted 9 June 2006

Copyright © 2006 Francisco Torrens and Gloria Castellano. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A method for the calculation of fractal surfaces of crystals is presented. The fractal dimension D of fragments of zeolites is calculated. Results compare well with reference calculations (GEPOL). The active site of Brønsted acid zeolites is modeled by a set of Al–OH–Si units. These units form 2–12-membered rings. Topological indices for the different active-site models are calculated. The comparison between GEPOL and SURMO2 allows calculating the active-site indices. Most cavities show no fractal character, while for the 6–8-unit rings, D lies in the range 4.0–4.3. The 6-ring shows the greatest D and is expected to be the most reactive.