Formation of Hierarchically Organized Zeolites by Sequential Intergrowth

摘要

Hierarchically organized porous materials can provide multidimensional spatial networks on different length scales with improved characteristics relevant to molecular diffusion. Zeolites that are microporous crystalline materials having pores and channels at molecular dimensions are of great importance for industrial applications.'21 However, the presence of only micropores in zeolite frameworks often limits the molecular diffusion and therefore, restricts the transport of bulky molecules. This problem can be resolved by shortening the effective diffusion path lengths, which has been achieved by miniaturizing zeolite crystals, delaminating or exfoliating layered zeolites, synthesizing zeolite nanosheets, and introducing mesopores into zeolite particles. Among these solutions, the fabrication of hierarchical zeolites with micro- and mesoporosity is of interest because it combines intrinsic micropores with bypass-interconnected mesopores, and therefore, enhances both the micropore accessibility and molecular traffic within zeolite particles.