Fractal Geometry Approach to Describe Mesostructured Boehmite and Gamma‐Alumina Nanorods

Abstract

Abstract Mesoporous boehmite and gamma‐alumina with nanorod‐like morphology, exhibiting a high surface area and large pore volume, have been prepared by a nonsurfactant‐templating sol–gel technique with a simple precursor system, aluminum isopropoxide, ethanol, 2‐propanol, or 2‐butanol as solvents, and sulfuric or hydrochloric acid as peptizing agents. The effect of the solvent‐type and the peptizing agent were studied, and optimum conditions were determined. A fractal geometry approach was adopted to describe the subtle alterations in the smoothness of the surface as a function of the synthesis conditions. Boehmite and γ‐alumina nanorods were characterized by nitrogen physisorption, wide‐ and small‐angle XRD, SAXS, 27 Al MAS NMR spectroscopy, TEM, and TGA–DTA. Both boehmite and gamma‐alumina nanorods have a large surface area, pore volume, and pore size.