Synthesis Of Highly Hydrothermal Stable And Extraordinarily High Catalytic Performance Mesoporous Materials

Since the discovery of M41S by Mobil's scientists in 1992, ordered mesoporous silicate materials have attracted intense attention for their high surface area, uniform pore size distribution, large pore size, and potential applications, such as catalysts, catalyst supports, adsorbents and so on. SBA-15 is one of the most important materials in the family of mesoporous materials for its better hydrothermal stability and larger pore diameter. To expend the applications of SBA-15, much effort has been focused on the incorporation of heteroatom and enhancing the hydrothermal stability.Extremely hydrothermal stable mesoporous silica Al-SBA-15 with controllable Al content has been synthesized in a simple procedure only using one surfactant (P123) as template under the assistance of NaF at 160℃with a high pH value adjusted. This material was characterized by powder X-ray diffraction (XRD), N2 sorption isotherms, TEM,27Al MAS NMR, energy-dispersive X-ray spectroscopy (EDX), and NH3-TPD. It is found that synthesized Al-SBA-15 maintained the well-resolved SXRD patterns and high surface area, large pore size, thick pore wall and high pore volume after being hydrothermally treated at 100℃for 300 h or steamed at 600℃for 6 h and almost all the All added into the initial reaction mixture can be introduced into the products. The Al-SBA-15 is efficient catalyst for protection of carbonyl compounds reactions under mild conditions and in short reaction times.A series of catalysts with different copper content and Si/Al ratios were characterized by small X-ray diffraction, N2 adsorption-desorption and the catalytic activity in the reaction of phenol hydroxylation. It showed that the catalyst has a very high conversion in a lower copper content condition. With the copper content increased, the conversion wasn't increased, but the mesostructure became unordered. The phenol hydroxylation with Al-SAB-15 catalyst support has higher catalytic activity and stability than SBA-15 for 5 cycles. This may be ascribed to the increasing of the surface electric charge associated with Al cations and making the Cu dispersed uniform.