Ten Years of Aberration Corrected Electron Microscopy for Ordered Nanoporous Materials

Li, Chengmin; Zhang, Qing; Mayoral, Álvaro

doi:10.1002/cctc.201901861

Cited by 31 publications

(21 citation statements)

References 169 publications

(81 reference statements)

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“…According to the literature, zeotypes have been considered the primary technological, nano-porous, inorganic substances, with more than 180 framework topologies. In addition to aluminosilicate zeolites, researchers have identified several zeolites, such as inorganic materials, in the 1980s and 90s, including transition metal phosphates (MeAPOs) and aluminium phosphates (AlPOs) [1][2][3]. Moreover, experts in the field have performed numerous studies on the development new classes of zeolitic structures on the basis of hybrid metal organic framework materials (MOFs).…”

Section: Introductionmentioning

confidence: 99%

Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications

et al. 2022

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Metal organic frameworks (MOF) are a class of hybrid networks of supramolecular solid materials comprising a large number of inorganic and organic linkers, all bound to metal ions in a well-organized fashion. Zeolitic imidazolate frameworks (ZIFs) are a sub-group of MOFs with imidazole as an organic linker to metals; it is rich in carbon, nitrogen, and transition metals. ZIFs combine the classical zeolite characteristics of thermal and chemical stability with pore-size tunability and the rich topological diversity of MOFs. Due to the energy crisis and the existence of organic solvents that lead to environmental hazards, considerable research efforts have been devoted to devising clean and sustainable synthesis routes for ZIFs to reduce the environmental impact of their preparation. Green chemistry is the key to sustainable development, as it will lead to new solutions to existing problems. Moreover, it will present opportunities for new processes and products and, at its heart, is scientific and technological innovation. The green chemistry approach seeks to redesign the materials that make up the basis of our society and our economy, including the materials that generate, store, and transport our energy, in ways that are benign for humans and the environment and that possess intrinsic sustainability. This study covers the principles of green chemistry as used in designing strategies for synthesizing greener, less toxic ZIFs the consume less energy to produce. First, the necessity of green methods in today’s society, their replacement of the usual non-green methods and their benefits are discussed; then, various methods for the green synthesis of ZIF compounds, such as hydrothermally, ionothermally, and by the electrospray technique, are considered. These methods use the least harmful and toxic substances, especially concerning organic solvents, and are also more economical. When a compound is synthesized by a green method, a question arises as to whether these compounds can replace the same compounds as synthesized by non-green methods. For example, is the thermal stability of these compounds (which is one of the most important features of ZIFs) preserved? Therefore, after studying the methods of identifying these compounds, in the last part, there is an in-depth discussion on the various applications of these green-synthesized compounds.

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Section: Introductionmentioning

confidence: 99%

Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications

et al. 2022

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“…[8] Ag ood example of the minimum requirements for the next generation of functional porous materials concerning the analysis of all T-atoms (Al and P) in an e-beam sensitive AlPO 4 (STA-20), which were directly observed by C s -corrected STEM-ADF imaging. [9] In the present work, we demonstrate that two fundamental challenges in the direct atomic-level imaging of zeolites have now been solved:F irst, observing all framework atoms, including O-atoms,i no ne of the most e-beam sensitive and lowest framework density zeolites,N a-LTA (with Si/Al % 1). Fort his analysis,a na nnular bright field detector (ABF) was employed for the first time in the study of zeolites.T o corroborate the feasibility of this approach, silicalite-1 (MFItype) was also imaged clearly observing the O-atoms.D irect observation of O-atoms is very important, since their positions are very sensitive to the presence of cationic species such as H + ,w hich play ac rucial role in the catalytic performance of zeolites.S econd, direct observation of single transition-metal (Fe) heteroatoms in silicalite-MFI zeolite, showing clear evidence of an on-periodic distribution of Fe within the framework.…”

Section: Introductionmentioning

confidence: 69%

Direct Atomic‐Level Imaging of Zeolites: Oxygen, Sodium in Na‐LTA and Iron in Fe‐MFI

et al. 2020

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Zeolites are becoming more versatile in their chemical functions through rational design of their frameworks.T herefore,d irect imaging of all atoms at the atomic scale,b asic units (Si, Al, and O), heteroatoms in the framework, and extra-framework cations,i sn eeded. TEM provides local information at the atomic level, but the serious problem of electron-beam damage needs to be overcome.H erein, all framework atoms,i ncluding oxygen and most of the extraframework Na cations,are successfully observed in one of the most electron-beam-sensitive and lowest framework density zeolites,N a-LTA.Z eolite performance,f or instance in catalysis,i sh ighly dependent on the location of incorporated heteroatoms.Fesingle atomic sites in the MFI framework have been imaged for the first time.T he approach presented here, combining image analysis,e lectron diffraction, and DFT calculations,c an provide essential structural keys for tuning catalytically active sites at the atomic level.

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“…The morphology and distribution of Rh species in Rh/C PBI ‐MMZ‐as and Rh‐MMZ were characterized by energy‐dispersive X‐ray (EDX) spectral mapping. To corroborate the existence and location of the metals within the zeolitic structures, we turned to C s ‐corrected STEM coupled with a high angle annular dark field detector (HAADF), as this is the most accurate approach to characterize metal loaded zeolites [41] …”

Section: Resultsmentioning

confidence: 99%

Library Creation of Ultrasmall Multi‐metallic Nanoparticles Confined in Mesoporous MFI Zeolites

et al. 2021

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The development of materials integrated with ultrasmall multi‐metal nanoparticles (UMMNs) and mesoporous zeolite is a considerable challenge in chemistry and materials science. We designed a trifunctional surfactant, in which the pyridyl benzimidazole in the hydrophobic tail generates the mesopores through π–π stacking; the diquaternary ammonium in the hydrophilic headgroup direct the formation of MFI zeolite sheets and the nitrogen atoms in the heterocyclic rings coordinate with various metal ions to form UMMNs confined in the zeolite matrix after calcination and reduction. A library of 56 UMMNs confined within both micropores and mesopores of MFI zeolites (MMZs) with 4 mono‐, 14 bi‐ and 38 tri‐metallic nanoparticles (sizes of 1.3–4.7 nm) of combinations of Rh, Pd, Pt, Au, Fe, Co, Ni, Cu and Zn were made. An improved catalytic performance was exhibited in the sequence of Rh‐MMZ

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Ten Years of Aberration Corrected Electron Microscopy for Ordered Nanoporous Materials

Cited by 31 publications

References 169 publications

Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications

Green Synthesis of Zeolitic Imidazolate Frameworks: A Review of Their Characterization and Industrial and Medical Applications

Direct Atomic‐Level Imaging of Zeolites: Oxygen, Sodium in Na‐LTA and Iron in Fe‐MFI

Library Creation of Ultrasmall Multi‐metallic Nanoparticles Confined in Mesoporous MFI Zeolites

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