Effect of crystallization time on the physico-chemical and catalytic properties of the hierarchical porous materials

Influence of Al content on textural properties and catalytic activity of hierarchical porous aluminosilicate materials

“…BET surface area, microporous area and mesoporous area of the hierarchical porous materials C-Xh (25) are all higher than those of C-Xh (50) reported in our previous work with the same crystallization time (Xu et al 2010). For example, BET surface area and mesoprous area of C-36h (25) are 535 and 368 m 2 /g, respectively which are larger than those of C-36h (50) reported in our preliminary work (382 and 105 m 2 /g) (Xu et al 2010). This suggests that variation of Al content in the initial gel can alter the porous parameters of the hierarchical porous aluminosilicate materials.…”

“…XRD pattern of C-16h (25) exhibits characteristic peaks indexed as amorphous structures (figure 1a). To our knowledge, when crystallization time was 16 h, XRD pattern of the sample C-16h with n Si /n Al = 50 exhibited the diffraction peaks assigned to MFI structure (Xu et al 2010). Compared to the sample of C-16h (25) obtained from a high Al content with the reported sample of C-16h (50) obtained from a low Al content in the initial gel, we can find that crystallization rate decreases with increased Al content in the initial gel.…”

“…The isotherms of C-16h (25), C-22h (25) and C-36h (25) exhibit type IV with H1 hysteresis loops (as shown in figure 2(a)), which indicates the presence of a mesoporous structure in the samples that have a crystallization time of ≤ 36 h. To our knowledge, the isotherm of C-36h (50) reported in our previous work was type I ascribed to the microporous structure (Xu et al 2010). Compared to the isotherm of C-36h (25) obtained from a high Al content with that of C-36h (50) obtained from a low Al content (Xu et al 2010), results suggest that variation of Al content in the synthesis gel can affect the textural structure of the hierarchical porous aluminosilicate materials.…”

“…To prepare the hierarchical porous aluminosilicate materials, tetraethoxysilane and aluminum sulfate were used as the silica and aluminum source, respectively. The detailed synthesis procedures were in accordance with our previous report (Xu et al 2010). The only difference was the addition of Al content with Si/Al molar ratio of 25 (n Si /n Al = 25) in the initial gel.…”

“…In our preliminary work, we studied the hierarchical porous aluminosilicate materials and investigated the effect of crystallization time on the physico-chemical and catalytic properties (Xu et al 2010). The results showed that catalytic performance of the hierarchical porous aluminosilicate materials was determined by acidity and pore structures.…”