The fractal and percolation analysis of a polymeric Al2O3 gel

Fractal and percolation analysis have been performed on nitrogen adsorption isotherms of polymeric Al2O3 xerogel, prepared from a low-water non-aqueous solution of aluminum alkoxide. These xerogels showed a distinctively low pore connectivity compared to that reported in the literature on more conventional alumina gels. The alumina xerogel exhibited a surface fractal behavior in the scale range from nitrogen size to a few nanometers. The mean pore coordination number and the surface fractal dimension of the xerogel were rather stable upon calcination, until the appearance of the α-alumina crystalline phase, despite of a large decrease in BET surface area and pore volume.