Zeolite nanosheet of a single-pore thickness generated by a zeolite-structure-directing surfactant

Abstract

Zeolite MFI nanosheets have been hydrothermally synthesized using a surfactant with the formula [C 18 H 37 -N + (CH 3 ) 2 -C 6 H 12 -N + (CH 3 ) 2 -C 6 H 12 -N + (CH 3 ) 2 -C 18 H 37 ][Br À ] 3 as the zeolite structure-directing agent. These nanosheets correspond to a slice of MFI zeolite crystal of 1.5 nm thickness in the b-direction. Each nanosheet is composed of a monolayer of micropores, which is thinner than a single crystal unit-cell dimension (2.0 nm). Such a single-pore zeolite nanosheet still exhibits high thermal stability, steam stability, acid strength and shape-selective catalytic activity, comparable to the bulk crystal.

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

“…In addition to the MFI and BEA zeolite reported above, various other zeolite framework structures such as MRE and MTW were synthesized in the form of nanostructures using cationic surfactants containing three or more ammonium ions [73,82,83,[86][87][88]. The hydrophobic tails in the dual-pore-generating surfactant have two important roles according to the literatures reported so far.…”

Influence of downsizing of zeolite crystals on the orthorhombic ↔ monoclinic phase transition in pure silica MFI-type

“…A1c), the thickness of each individual nanosheet being of the same order of magnitude as the unit cell parameter b of the MFI topology, i.e. less than 2 nm [22e24, 30]. Due to the particularly low resolution of the PXRD patterns, it is not possible to distinguish here a monoclinic or orthorhombic lattice.…”

Mesostructured Zeolites

“…4.15 ) [ 139 ]. Ultrathin nanosheets (~1.5 nm), with only ¾ of the b lattice parameter, were even synthesized by using a Gemini-type tri-ammonium surfactant with the formula of C 18 [ 140 ].…”