Synthesis of hierarchically porous silicate-1 and ZSM-5 by hydrothermal transformation of SiO2 colloid crystal/carbon composites

Hierarchically porous silicate-1 and ZSM-5 zeolites were successfully prepared by a hydrothermal crystallization process in the presence of SiO2 colloid crystal/carbon composite. The inter-crystalline mesopores and macro pores were successfully created inside these zeolite materials. The effect of synthesis conditions including hydrothermal reaction temperature, reaction time, silica source and aluminum source on the morphology and porous structure were studied in detailed. All the samples were characterized by XRD, SEM, N-2 adsorption desorption analysis and NH3-TPD. The advantage of hierarchically porous structure was evaluated by the catalytic application. The hierarchically porous ZSM-5 as a catalyst displayed higher catalytic activity than the conventional ZSM-5 when using the acetalization reaction of cyclohexanone as a model reaction.