Highly hydrothermally stable Al-MCM-41 with accessible void defects

Abstract Mesoporous aluminosilicates (Al-MCM-41) with high hydrothermal stability were synthesized via self-assembly of nanoseed precursors, obtained from alkali-treatment of ZSM-5. Characterized by $ N_{2} $ sorption, Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray...
Ausführliche Beschreibung

Abstract Mesoporous aluminosilicates (Al-MCM-41) with high hydrothermal stability were synthesized via self-assembly of nanoseed precursors, obtained from alkali-treatment of ZSM-5. Characterized by $ N_{2} $ sorption, Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and Mercury intrusion, as-prepared Al-MCM-41 possessed a large number of void defects, enhancing the connectivity of MCM-41. The effects of alkali-treatment degree, including time and concentration, on volume of void defects were investigated and discussed. It is revealed that volume of void defects decreased in the severe condition of alkali-treatment, and void defects representing the intraparticular pores account for a volume of 0.138 $ cm^{3} $/g in Al-MCM-41, prepared under the condition of 1.0 mol/L of NaOH and 1 h of stirring time. A tentative proposed mechanism for interpreting the formation of void defects was presented. Aggregated secondary building units in the precursors not only provided Si (Al) sources, but also functioned as templates for the development of void defects. Al-MCM-41 with void defects would be beneficial to diffusion and mass transportation. Ausführliche Beschreibung