quantitative morphological analysis of nanostructured ceria-silica composite catalysts

• Published in: Journal of microscopy (Oxford) 2008-11, Vol.232 (2), p.293-305
• Main Authors: MOREAUD, M, JEULIN, D, THOREL, A, CHANE-CHING, J.Y
• Format: Article
• Language: English
• Subjects: Catalyst; ceria; Condensed Matter; HRTEM; interclass variance maximization; Materials Science; mathematical morphology; mesoporous material; Physics
• ISSN: 0022-2720; 1365-2818
• DOI: 10.1111/j.1365-2818.2008.02101.x

This study aims at examining the morphology of different catalysts, which are based on a dispersion of ceria nanoparticles embedded in a high surface area mesoporous silica framework. In order to fully describe the mesostructured composite material, we propose here a quantitative description of the microstructure based on a quantitative analysis of micrographs that were obtained via high-resolution transmission electron microscopy. We have therefore developed an automatic image analysis process in order to automatically and efficiently extract all the components of the catalyst images. A statistical and a morphological analysis of the spatial arrangement of the components of the catalyst are also presented. The study shows clear differences between the materials analysed in terms of the spatial arrangement and the total surface area of the ceria phase emerging into the pores, parameters of prime importance for the catalytic properties. Thus, the silica-ceria nanostructured composite materials, displaying large surface area up to 300 m² g⁻¹ are shown to exhibit highly rugged surfaces resulting from ceria nanoparticles emerging in the pores.