# Influence of Synthesis Parameters in Obtaining KIT-6 Mesoporous Material
## 3 Results and Discussions
A similarity between the KMT and KEt samples (6.2 and 6.5 nm, respectively) can be noted, while the KPr sample shows a significantly inferior value (about 1.3 nm). This behavior relates to the values of interplanar distance and mesoporous parameter for the unidirectional hexagonal structure. This set of facts reveals that the  
Figure 6: Pore size distribution (PSD) of the (**A**) standard KIT-6 and (**B**) KDT2 samples. type of alcohol used in the synthesis acts only as a co-solvent for the formation of the SBA-15 structure, slightly modifying the textural properties, but not significantly interfering in the micellar formation. The samples that displayed 3D cubic structure in the modification of aging time of the synthesis gel (KAT18 and KAT30 samples) presented values of average pore diameter and wall thickness similar to the standard KIT-6 material. Such a result suggests that this synthesis parameter does not significantly interfere in the formation and micellar organization. However, as discussed earlier, there is an optimal equilibrium time of 24 h to promote better textural properties values (S\({}_{\text{BET}}\), V\({}_{\text{MESO}}\) and V\({}_{\text{T}}\)), based in the stages of hydrolysis of the silica and condensation of the inorganic phase. From this, it is of great relevance to point out that the aging time of synthesis gel favors the 3D cubic structure for the KIT-6 material starting from 18 h of procedure, reaching the best textural properties in 24 h.  
Analyzing the samples obtained in the variation of thermal treatment time, this denotes a small increase in the average pore diameter (0.4 nm) and a slight decrease in wall thickness (0.3 nm), when comparing the shortest time studied (KHT12 sample) with the longest (KHT30 sample). These results reveal that the modification of thermal treatment time, in which occurs the condensation of the silanol groups, does not significantly influence the micellar formation and consequently the average pore diameter. However, the thermal treatment time acts considerably in the synthesis mechanism, increasing the values of the textural properties (specific area, mesoporous volume and total volume), when compared to the 12 and 30 h times (see Table 2). Nevertheless, it is important to emphasize that, starting with 12 h of thermal treatment, the 3D cubic structure is formed with relevant textural properties. With an increase in 6 h at a time between the KIT-6 and KHT30 samples, the 3D cubic structure reflects similar textural properties. Figure 7 exhibits TEM micrographs of KDT4 and KHT12 representative samples. Figure 7: Representative transmission electron microscope (TEM) images of **(A)** KDT4 and **(B)** KHT12 samples. The images of the KDT4 and KHT12 samples are presented in a representative way for the materials that showed a 3D cubic structure. Analyzing the TEM micrographies of these materials, it was observed along the axis [001] that the two samples showed well-defined pore organization. When analyzing the image along the axis [010], it can be clearly noticed that the channel curvatures refer to the type of bi-continuous channels respective to KIT-6 mesoporous materials. Such behavior can also be visualized in studies described in the literature [9; 45]. These results corroborate those found in the XRD technique and N\({}_{2}\) adsorption-desorption isotherms. Through this technique, the pore diameter of these materials was also measured. The KDT4 and KHT12 samples presented average values of 6.4 \(\pm\) 1.23 and 5.9 \(\pm\) 0.95 nm for the pore diameters, respectively. These values are very similar to those found in the pore size distribution (PSD), calculated by the VBS method in the desorption branch through N\({}_{2}\) adsorption-desorption isotherms.