The scope of this thesis is to better understand the world around us and our perception of its phenomena. This study is embedded in a wide sphere of interest that comprehends mathematical modeling, porosity, diffusion and catalysis. The goal is to understand how Fickian diffusion may be simulated into a reproduced porous network of γ−Al2O3 with an innovative analysis by a PFG-NMR characterization. A proper description of the topology of the porous network is in fact vital to understand how to accurately design the catalyst, enhancing the prediction of reactions. γ-Alumina is the most important phase of alumina. It presents the higher surface area, porosity and it has been studied and exploited for the acidity of its surface that promotes catalytic performances.