Interzeolite conversion, a synthesis technique for several zeolite frameworks, has recently yielded a large amount of high-performing catalytic zeolites. Yet, the mechanisms behind the success of interzeolite conversion remain unknown. Conventionally, small oligomers with structural similarity between the parent and daughter zeolites have been proposed, despite the fact these have never been observed experimentally. Moreover, recent synthesis examples contradict the theory that structural similarity between the parent and daughter zeolites enhances interzeolite conversion. In this perspective it is proposed that heteroatoms, such as aluminium, are key players in the processes that determine the successful conversion of the parent zeolite. The role of Al during parent dissolution, and all consecutive stages of crystallization, are discussed by revising a vast body of literature. By better understanding the role of Al during interzeolite conversions, it is possible to elucidate some generic features and to propose some synthetic guidelines for making advantageous catalytic zeolites. The latter analysis was also expanded to the interconversion of zeotype materials where heteroatoms such as tin are present.

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On the key role of aluminium and other heteroatoms during interzeolite conversion synthesis

Multi-agent-based approach for generation expansion planning in isolated micro-grid with renewable energy sources and battery storage

Organic and inorganic structure-directing agents (SDAs) impact Al distributions in zeolite, but the insights into how SDAs manipulate Al distribution have not been elucidated yet. Herein, the roles of different SDAs such as cyclohexylamine (CHA), hexamethylenimine (HMI), and Na+ in selective Al substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR. The results demonstrate that MCM-49 synthesized with HMI shows relatively more T6 and T7 Al, while more T2 Al is observed using CHA. The formation of T2 Al in both MCM-49(HMI) and MCM-49(CHA) is derived from Na+, while protonated HMIs show bias in incorporation of T6 and T7 Al. Most HMIs are occluded in protonated status, and about half of CHAs are occluded in nonprotonated status. The close spatial proximity between nonprotonated CHAs and Na+ synergistically promotes the formation of zeolite structure, leading to more Na+ ions occluded in the zeolite channel with preferential T2 Al substitution.

The Role of Organic and Inorganic Structure-Directing Agents in Selective Al Substitution of Zeolite.

Rational Design and Targeted Synthesis of Small-Pore Zeolites with the Assistance of Molecular Modeling, Structural Analysis, and Synthetic Chemistry

The authors acknowledge the financial support from the Technology Mission Division (Department of Science and Technology, Government of India) under the Materials for Energy Storage (MES-2018) program (DST/TMD/MES/2K18/207). S.S. and P.K.J. thank the Ministry of Human Resource Development (MHRD) for financial support. P.K.J. thanks Prof. M. Shrivastava and Prof. S. G. Gopalakrishnan for computational resources and scientific discussions, respectively. H.N.A. is grateful to the King Abdullah University of Science and Technology (KAUST) for partial financial support. A.N. and K.J. sincerely acknowledge financial support from the U.S. Department of Energy, Office of Basic Energy Sciences, Grant DE-FG02-03ER46053.

Marinite Li2Ni(SO4)2 as a New Member of the Bisulfate Family of High-Voltage Lithium Battery Cathodes

Organic structure-directing agents (SDAs) play a crucial role in the synthesis of zeolites like SSZ-13 (CHA structure), with novel frameworks and compositions. Zeolite crystallization is aided by t...

K. Jayanthi

Papers

Energetics of the Local Environment of Structure-Directing Agents Influence Zeolite Synthesis

Marinite Li2Ni(SO4)2 as a New Member of the Bisulfate Family of High-Voltage Lithium Battery Cathodes