Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (05): 1035-1040.doi: 10.3866/PKU.WHXB201302223

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Synthesis of Hierarchical MgO-Containing Silicalite-1 Zeolites with High Hydrothermal Stability

CHEN Hong-Li, DING Jian, WANG Yi-Meng   

  1. Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062, P. R. China
  • Received:2012-11-15 Revised:2013-02-21 Published:2013-04-24
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20890124) and National Key Technology R&D Program, China (2012BAE05B02).

Abstract:

Hierarchical MgO/silicalite-1 composites were synthesized via hydrothermal treatment of MgO-supported porous silica using tetrapropylammonium hydroxide (TPAOH) as a template. MgO species were introduced into porous silica via solid-state grinding and subsequent calcination. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) results indicated that MgO was uniformly distributed in the zeolite crystals. The hydrothermal stability of MgO/ silicalite-1 before and after acid washing was detected by treatment at 800℃ in 100% steam for 10 h. The introduction of MgO increased the hydrothermal stability of MgO/silicalite-1 samples. Furthermore, acid washing could remove MgO impurities, increasing the relative crystallinity of samples compared with that of calcined MgO/silicalite-1 and introducing mesopore into zeolite simultaneously. N2 adsorption-desorption measurements indicated that mesopores were generated in the zeolite crystals by the removal of MgO species. The improved hydrothermal stability and the generation of mesopores in these MgO/silicalite-1 samples play important roles in preserving zeolite structure, enhancing coke tolerance, slowing deactivation, and extending catalyst life during high-temperature reaction.

Key words: MgO, Zeolite, Hydrothermal stability, Hierarchical porosity

MSC2000: 

  • O643