Carbon Nanotube Templated Growth of Mesoporous Zeolite Single Crystals

Abstract

Carbon nanotubes are shown to be useful materials for introduction of nanopores with a controlled diameter into zeolite single crystals. The intracrystalline nanopores are created by crystallization of the zeolite around the carbon nanotubes that are subsequently removed by combustion.

Well‐Organized Zeolite Nanocrystal Aggregates with Interconnected Hierarchically Micro–Meso–Macropore Systems Showing Enhanced Catalytic Performance

“…Recently, various successful attempts to synthesize mesoporous or macroporous zeolites with bimodal porosity and framework acidity have been reported. [4][5][6][7][8][9][10][11][12][13][14][15] These materials hold great promise, particularly in catalysis and separation processes in which optimization of the diffusion and confinement regimes is required. Whereas micro-and/or mesopores provide size and shape selectivity for the guest molecules, and thus enhance the host-guest interactions, the presence of macropores can considerably favor diffusion of the guest molecules and thus their access to the active sites.…”

Why are carbon molecular sieves interesting?

“…As expected, the material exhibits a bimodal distribution of pores, with 0.09 mL g -1 of micropores with ~0.5 nm diameter and 1.01 mL g -1 of mesopores with diameters ranging from 5-50 nm. 34 The same synthesis strategy with the aid of carbon nanotubes instead of carbon mesoporous matrices, Scheme 7, 35 leads to longer mesopores within the zeolite single crystals. The comparison of the transmission electron micrographs in Figure 14 shows the difference in the materials obtained with both procedures and that the particle obtained is a zeolite single crystal and not an aggregate, as could be suggested by the morphology and the surface rugosity of the crystals.…”

An Overview of Zeolite, Zeotype and Mesoporous Solids Chemistry: Design, Synthesis and Catalytic Properties

“…[74] A different approach towards zeolites containing mesopores involves the incorporation of a template with mesoscopic dimensions into the zeolite synthetic procedure. Carbon spheres and carbon nanotubes have been used for this purpose, [75] the latter with a typical diameter of 12 nm and several micrometres long. The synthesis of mesoporous silicalite-I, which is reported in this paper, simply involves the incorporation of the carbon nanotubes into the synthesis gel also containing TPAOH and TEOS.…”