Thermal Conductivity of Covalent Organic Frameworks as a Function of Their Pore Size

Freitas, Sunny K. S.; Borges, Raquel S.; Merlini, Claudia; Barra, Guilherme Mariz de Oliveira; Esteves, Pierre M.

doi:10.1021/acs.jpcc.7b10487

Cited by 47 publications

(52 citation statements)

References 43 publications

(62 reference statements)

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“…2 and Table 1). Of the microporous materials, RIO-11, RIO-12 and RIO-13 are built of hydrazine and hydroxy-1,3,5-triformylbenzenes (Maia et al, 2018); and RIO-4 (Freitas et al, 2017) and RIO-14 are formed by the aldehydes 1,3,5-triformylphenol and 1,3,5-triformylresorcinol, respectively, and share the same amine building block tetrakis(4-aminophenyl)methane. As far as we know, RIO-14 has not been reported yet (see Section 2 of the supporting information for detailed synthesis and characterization).…”

Section: Methodsmentioning

confidence: 99%

“…FeCl 3 @TPB-DMTP-COF 7.8% and FeCl 3 @TPB-DMTP-COF 12% have 7.8 and 12% of iron incorporated (Cifuentes et al, 2018) into the pristine TPB-DMTP-COF, respectively. Details of the characterizations and synthetic procedures, N 2 adsorption-desorption isotherms, PXRD, FT-IR, solid-state 13 C NMR, and DFT calculations regarding the materials used for SAXS analyses can be found in their respective references: RIO-11, RIO-12 and RIO-13 (Maia et al, 2018); RIO-4 (Freitas et al, 2017); TPB-DMTP-COF and FeCl 3 @TPB-DMTP-COF (Cifuentes et al, 2018); RIO-14, [HC C] 0.17 TPB-DMTP-COF, TPB-DMTP-COF SU4 and TPB-DMTP-COF SU5 in Section 2 of the supporting information.…”

Section: Methodsmentioning

confidence: 99%

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Small-angle X-ray scattering as a multifaceted tool for structural characterization of covalent organic frameworks

et al. 2020

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Small-angle X-ray scattering (SAXS) is an accurate nondestructive method that requires a minimum of sample preparation and is employed to study porosity, morphology and hierarchical structures. Zeolites and silica are among the porous materials that are widely investigated by SAXS. However, studies of covalent organic frameworks (COFs) are still scarce. In the present study, SAXS was employed to investigate meso- and microporous COFs, affording insightful information about their nanostructure textural properties. SAXS is especially useful when combined with other characterization techniques, such as powder X-ray diffraction and N2 adsorption isotherms, emerging as an efficient tool to further characterize COFs. For microporous COFs, SAXS was used mainly to obtain quantitative values of surface roughness as a function of fractal parameters, in all cases indicating surface fractals of the large-scale scattering object, namely the `grain'. Mesoporous COF studies allowed elucidation of their hexagonal structure on the basis of their structure peaks; however, the main result lies in the distinction between the pore and the grain, which are described as a hierarchical structure by the Beaucage model and evaluated according to their fractality. These COFs generally exhibit pores with mass fractal features and grains with surface fractal features when they are submitted to post-functionalization, which may be due to the poor diffusivity of the functionalizing agents into the pores. In addition, a proposed aggregation description of the porous scattering objects was envisioned, based on small-angle scattering premises, which was confirmed for a microporous COF by high-resolution transmission electron microscopy.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Small-angle X-ray scattering as a multifaceted tool for structural characterization of covalent organic frameworks

et al. 2020

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“… 99 , 231 In packed beds, this transport mainly occurs through the porous particle contact points, lowering at least 1 order of magnitude the pristine (crystal) MOF values. 396 , 397 The use of binders and coatings is used to alleviate this drawback. 280 , 336 Because not only conduction plays a role but also the heat capacity of the materials, a better parameter to characterize the thermal transport is the thermal diffusivity a = λ/(ρ· c p ) [m 2 s –1 ] that describes how fast temperature profiles move in the system (see Figure 2 ).…”

Section: Evaluation and Outlookmentioning

confidence: 99%

Water and Metal–Organic Frameworks: From Interaction toward Utilization

2020

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The steep stepwise uptake of water vapor and easy release at low relative pressures and moderate temperatures together with high working capacities make metal–organic frameworks (MOFs) attractive, promising materials for energy efficient applications in adsorption devices for humidity control (evaporation and condensation processes) and heat reallocation (heating and cooling) by utilizing water as benign sorptive and low-grade renewable or waste heat. Emerging MOF-based process applications covered are desiccation, heat pumps/chillers, water harvesting, air conditioning, and desalination. Governing parameters of the intrinsic sorption properties and stability under humid conditions and cyclic operation are identified. Transport of mass and heat in MOF structures, at least as important, is still an underexposed topic. Essential engineering elements of operation and implementation are presented. An update on stability of MOFs in water vapor and liquid systems is provided, and a suite of 18 MOFs are identified for selective use in heat pumps and chillers, while several can be used for air conditioning, water harvesting, and desalination. Most applications with MOFs are still in an exploratory state. An outlook is given for further R&D to realize these applications, providing essential kinetic parameters, performing smart engineering in the design of systems, and conceptual process designs to benchmark them against existing technologies. A concerted effort bridging chemistry, materials science, and engineering is required.

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“…Covalent Organic Networks (CONs) are a class of 2D porous reticulated materials built-up by organic building blocks presenting different topologies in a predictable manner that is comparable to a molecular equivalent of interlocking toy bricks [11]. Their topologically well-defined chemical structures make these porous materials promising candidates for use in a myriad of important applications such as gas adsorption [12], proton conduction [13], optoelectronics [14], energy storage [15], catalysis [16], among others [17]. However, despite the many potential interesting applications of these materials, one of the main drawbacks of their large-scale production is their cost.…”

Section: Introductionmentioning

confidence: 99%

Dye-based covalent organic networks

et al. 2020

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This contribution presents four dye-based CONs derived from the reaction of triformylphloroglucinol with thionin acetate (RIO-43), safranin chloride (RIO-51), phenosafranin (RIO-47), and Bismarck brown Y (RIO-55). These materials, called Covalent Organic Networks (CONs), are insoluble solids formed by organic lamellar stacked structures and present permanent porosity, light absorption across the whole visible spectrum, fluorescence, ion exchange capability, and ion and electron conductivity. Periodic DFT calculations carried out indicated that the bent nature of most of those building blocks affords conductive extended materials containing pores with the shape of three-petal flowers, with the anion positioned at the petals. The turbostratic disorder makes only the center of the flower-shaped pores accessible, decreasing the specific surface areas. The material that has a higher surface area is the one derived from thionin acetate (RIO-43), such as the highest electrical conductivity (1.96 × 10 -5 S cm −1 ), followed by RIO-47 (1.12 × 10 -7 S cm −1 ), RIO-55 (1.58 × 10 -7 S cm −1 ) and RIO-51 (3.26 × 10 -7 S cm −1 ).

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Thermal Conductivity of Covalent Organic Frameworks as a Function of Their Pore Size

Cited by 47 publications

References 43 publications

Small-angle X-ray scattering as a multifaceted tool for structural characterization of covalent organic frameworks

Small-angle X-ray scattering as a multifaceted tool for structural characterization of covalent organic frameworks

Water and Metal–Organic Frameworks: From Interaction toward Utilization

Dye-based covalent organic networks

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