Competition balance between mesoporous self-assembly and crystallization of zeolite: A key to the formation of mesoporous zeolite

Hierarchization of USY Zeolite by NH4OH. A Postsynthetic Process Investigated by NMR and XRD

“…[2][3][4] To minimize diffusion problems various synthetic approaches have been developed, targeting for instance extralarge pore zeolites, 5,6 nanosized zeolite particles, 7,8 layered zeolite-nanosheets, [9][10][11] and hierarchical porous composites. [12][13][14][15][16][17] Post-synthesis modifications such as dealumination and desilication, have been found to be particularly convenient and efficient. 3,[18][19][20][21] Among these, treatment with bases was identified as powerful and elegant method preserving crystallinity and acidic properties of the parent zeolite, while mesoporosity was introduced.…”

Synthesis of hierarchical ZSM-12 nanolayers for levulinic acid esterification with ethanol to ethyl levulinate

“…The excessive amount of TPOAC can cause the adsorptive competition of the organosilane surfactant on zeolite precursor surfaces, eventually resulting in the loss of the long-range order of zeolite structures. 38 It is therefore reasonable to propose the formation process of ZSM-12 nanolayer assemblies as demonstrated in Scheme 1. Since, the introduction of TPOAC has a considerable inuence on the crystallization of ZSM-12 nanolayers, the suitable amount of TPOAC is required in order to obtain homogeneous ZSM-12 nanolayers with the well-dened structure as well as high crystallinity.…”

Synthesis, characterization, and catalytic performance of hierarchical ZSM-11 zeolite synthesized via dual-template route

“…For example, hierarchical ZSM-5 and Y zeolites have been prepared using CTAB, and their mesoporous structures can be tuned by the addition of the swelling agent 1,3,5-trimethylbenzene [23,24]. However, phase separation in the synthetic system is hard to avoid when CTAB is used as a mesoporogen, mainly because of weak binding between CTAB and silicate species [25]. Methods for solving this problem have been explored, such as microwave-induced assembly via ionic interactions between sulfonic acid-functionalized nanozeolites and counter cationic surfactants [26,27], and adjusting the pH value of the synthetic solution [25].…”

“…However, phase separation in the synthetic system is hard to avoid when CTAB is used as a mesoporogen, mainly because of weak binding between CTAB and silicate species [25]. Methods for solving this problem have been explored, such as microwave-induced assembly via ionic interactions between sulfonic acid-functionalized nanozeolites and counter cationic surfactants [26,27], and adjusting the pH value of the synthetic solution [25]. It was reported that microporous and mesoporous phases were formed with the assistance of structure-directing agents and surfactants, respectively [23].…”