Strategies for conversion between metal–organic frameworks and gels

Zhuang, Zeyu; Mai, Zehan; Wang, Tianyi; Liu, Dingxin

doi:10.1016/j.ccr.2020.213461

Cited by 45 publications

(29 citation statements)

References 112 publications

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“…Gels are colloidal or polymer networks formed by covalent or supramolecular bonds of colloidal particles or polymer monomers, which lead to continuous development of spatial network structure and gradual loss of fluidity. [18] The gel is usually soft, and the yield stress is limited and quite small. In recent years, researchers have been deepening the research on gels, and developed different types of gel materials, such as hydrogels, organic gels, and ionic gels, and their applications in biomedical, environmental treatment, gas adsorption, biosensors, and other aspects have been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Improving proton conductivity of metal organic framework materials by reducing crystallinity

Tang

et al. 2022

Applied Organom Chemis

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Developing a new type of proton conductive material is key to improve the energy conversion performance of proton exchange membrane fuel cell (PEMFC). In recent years, metal organic framework (MOF) matrix conductive materials have become one of the research hotspots in the field of MOF. However, the grain boundaries in MOF particles and MOF@polymer composite films make it difficult to form long‐range ordered proton transport channels. Reducing crystallinity and changing the internal structural properties of MOF matrix may effectively improve its proton conductivity. In this study, some synthesis strategies were used to induce the crystallinity of MOF matrix to improve the proton conductivity, and low‐crystallinity MOG materials were obtained. In all, eight materials were prepared. The morphology characterization and proton conductivity of MOF and MOG materials were studied to explore the influence of different crystallinities and internal structures on proton conductivity. The results explicitly indicated that for the hydrophilic materials, the proton conductivity of MOG‐MOF‐808, MOG‐UiO‐66, MOG‐HKUST‐1 was significantly improved, compared with the corresponding MOFs at 75% RH. Among them, MOG‐MOF‐808 and MOG‐UiO‐66 show strong water stability and thermal stability, ensuring that it can be applied in special and complex environments. For the hydrophobic ZIF‐8 and MOG‐ZIF‐8, both their proton conductivities are low due to the material characteristics and network structures, while the proton conductivity of MOG‐ZIF‐8 is also higher than that of ZIF‐8 at 303 K. The results show that the abundant low‐crystallinity network structure in MOG materials played a very important role in improving the proton conductivity of the hydrophilic materials.

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Section: Introductionmentioning

confidence: 99%

Improving proton conductivity of metal organic framework materials by reducing crystallinity

Tang

et al. 2022

Applied Organom Chemis

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“…22 In addition, compared with single-metal MOGs, bimetallic MOGs tend to have minor particles, larger volume and more metal active sites due to the introduction of heterogeneity. 23,24 Simultaneously, the most significant feature of the two-component is that the properties and structure of the gels can be easily modulated by altering the molar ratio of the component. Regulating the nano-structure of the ion conduction channel has proved to be a more realistic means to comply high proton conductivity, because the structural characteristics revise the kinetics and distance of the transition site, which determines the proton transport behavior.…”

Section: Introductionmentioning

confidence: 99%

Conductive NiMn-based bimetallic metal–organic gel nanosheets for supercapacitors

et al. 2021

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“…As an emerging route to the hierarchically porous macrostructures, the sol–gel-based process involving a transitional gel state produces single-component Zr-MOF xerogel or aerogel monoliths after ambient pressure or supercritical drying, respectively. , The MOF gel state is found to be a colloidal network of supramolecular aggregations of crystalline nanoparticles throughout the solvent . The principle for MOF gel formation is to modulate the synthetic conditions to kinetically facilitate initial nucleation and subsequent gelation until a more thermodynamically favorable precipitation process is outcompeted.…”

Section: Introductionmentioning

confidence: 99%

“…25,26 The MOF gel state is found to be a colloidal network of supramolecular aggregations of crystalline nanoparticles throughout the solvent. 27 The principle for MOF gel formation is to modulate the synthetic conditions to kinetically facilitate initial nucleation and subsequent gelation until a more thermodynamically favorable precipitation process is outcompeted. The absence of high pressure and inert binders avoids the corresponding structural collapse, adsorption capacity loss, and pore blockage.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Adsorption and Mass Transfer of Hierarchically Porous Zr-MOF Nanoarchitectures toward Toxic Chemical Removal

Wang¹,

Su²,

Zhao³

et al. 2021

ACS Appl. Mater. Interfaces

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Zirconium-based metal−organic frameworks (Zr-MOFs) have shown tremendous prospects as highly efficient adsorbents against toxic chemicals under ambient conditions. Here, we report for the f irst time the enhanced toxic chemical adsorption and mass transfer properties of hierarchically porous Zr-MOF nanoarchitectures. A general and scalable sol−gel-based strategy combined with facile ambient pressure drying (APD) was utilized to construct MOF-808, MOF-808-NH 2 , and UiO-66-NH 2 xerogel monoliths, denoted as G808, G808-NH 2 , and G66-NH 2 , respectively. The resulting Zr-MOF xerogels demonstrated 3D porous networks assembled by nanocrystal aggregates, with substantially higher mesoporosities than the precipitate analogues. Microbreakthrough tests on powders and tube breakthrough experiments on engineered granules were conducted at different relative humidities to comprehensively evaluate the NO 2 adsorption capabilities. The Zr-MOF xerogels showed considerably better NO 2 removal abilities than the precipitates, whether intrinsically or under simulated respirator canister/protection filter environment conditions. Multiple physicochemical characterizations were conducted to illuminate the NO 2 filtration mechanisms. Analysis on adsorption kinetics and mass transfer patterns in Zr-MOF xerogels was further performed to visualize the underlying structure−activity relationship using the gravimetric uptake and zero length column methods with cyclohexane and acetaldehyde as probes. The results revealed that the synergy of hierarchical porosities and nanosized crystals could effectively expedite the intracrystalline diffusion for the G66-NH 2 xerogel as well as alleviate the surface resistance for the G808-NH 2 xerogel, which led to accelerated overall adsorption uptake and thus enhanced performance toward toxic chemical removal.

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Strategies for conversion between metal–organic frameworks and gels

Cited by 45 publications

References 112 publications

Improving proton conductivity of metal organic framework materials by reducing crystallinity

Improving proton conductivity of metal organic framework materials by reducing crystallinity

Conductive NiMn-based bimetallic metal–organic gel nanosheets for supercapacitors

Enhanced Adsorption and Mass Transfer of Hierarchically Porous Zr-MOF Nanoarchitectures toward Toxic Chemical Removal

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