Determination of the fractal dimension of alumina using adsorption: Challenges of choosing appropriate adsorbates and analysis methods

作者：Capitaine Elsa M R; Hill Josephine M^*

来源：Canadian Journal of Chemical Engineering, 2012, 90(3): 637-645.

DOI：10.1002/cjce.20572

• fractal
• alumina
• characterisation
• and adsorption

The classical method for surface characterisation of the porous structure of the catalysts is nitrogen (N2) adsorption at -196 degrees C, which provides a catalyst surface area value valid for molecules similar in size to N2 (0.162?nm2/molecule). To complement and obtain more information about the materials, catalyst surfaces can be characterised using fractal geometry. The fractal dimension of a sample can be determined by the adsorption uptake of molecules of different sizes on the surface of interest in order to obtain a characteristic parameter of the surface geometry known as the fractal dimension, D. In this work, the value of D for a ?-alumina catalyst support has been determined (D?=?2.71 +/- 0.15) using different adsorbates (argon, nitrogen, isopropanol, pyridine, and n-butane). The decision process for choosing these adsorbates and the challenges of this type of characterisation method are discussed in this article.

• 出版日期2012-6