The N2 adsorption desorption isotherms of the g-Al2O3 support
and the calcined catalysts prepared by different impregnation sequences
are shown in Fig. 2(a) and (b), respectively. As shown in
Fig. 2(a), all samples exhibited type IV isotherms and similar hysteresis
loops to the H4 type, characteristic of mesopores typical for
layered structures according to IUPAC classification. The pore size distribution of the catalysts shown in
Fig. 2(b) were narrow at ~5.5 nm, indicating the presence of mesoporous
structures in all catalysts.