Textural features of highly ordered Al-MCM-41 molecular sieve studied by X-ray diffraction, nitrogen adsorption and transmission electron microscopy

摘要

The preparation of a Al-MCM-41 mesoporous materials has been carried out using silica-gel and pseudoboehmite as silica and aluminum sources, respectively, and surfactant cetyltrimethylammonium bromide as structure template. The textural properties of the calcined Al-MCM-41 were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and N_2 isothermal adsorption measurements. The hexagonal structure parameter a_o was calculated based on d_((100)) XRD reflection as 4.75 nm. TEM images revealed the formation of a well-ordered Al-MCM-41. Accordingly, nitrogen adsorption measurements (BJH) showed a material with very narrow distribution and medium pore diameter of 3.14 nm. Mesopore volume based on adsorbed nitrogen was 0.51 cm~3 g~(-1). Through a combination of XRD and N_2 adsorption data, the thickness of the channel walls of 1.61 nm could be calculated.