Defect Engineering: Tuning the Porosity and Composition of the Metal–Organic Framework UiO-66 via Modulated Synthesis

Shearer, Greig C.; Chavan, Sachin; Bordiga, Silvia; Svelle, Stian; Olsbye, Unni; Lillerud, Karl Petter

doi:10.1021/acs.chemmater.6b00602

Cited by 1,086 publications

(1,539 citation statements)

References 94 publications

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“…It can be seen that all these Zr-containingm aterials are amorphorousw ith only af ew broad diffractions, although Zr-FDCA andZ r-FDCA-T show clear and intense peaks at 2q % 7.58,w hich is the typical (111)r eflectiono fU iO-66(Zr) (Figure S2). [15] HR-TEM images of ZrO 2 ,Zr-FDCA, and Zr-FDCA-T further confirm their mostly amorphous structure (Figure 2A-C). Figure 2C shows that the introduction of CTAB and mesitylene for Zr-FDCA-T preparation leads to the formationo fw ormlike features, which may increase the surface area and porous structure despite the absence of lattice planes ( Figure 2D).…”

Section: Resultsmentioning

confidence: 67%

Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox Conversion of Biofuranics

Li¹,

Liu²,

Yang³

et al. 2017

ChemSusChem

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Biofuranic compounds, typically derived from C and C carbohydrates, have been extensively studied as promising alternatives to chemicals based on fossil resources. The present work reports the simple assembly of biobased 2,5-furandicarboxylic acid (FDCA) with different metal ions to prepare a range of metal-FDCA hybrids under hydrothermal conditions. The hybrid materials were demonstrated to have porous structure and acid-base bifunctionality. Zr-FDCA-T, in particular, showed a microspheric structure, high thermostability (ca. 400 °C), average pore diameters of approximately 4.7 nm, large density, moderate strength of Lewis-base/acid centers (ca. 1.4 mmol g ), and a small number of Brønsted-acid sites. This material afforded almost quantitative yields of biofuranic alcohols from the corresponding aldehydes under mild conditions through catalytic transfer hydrogenation (CTH). Isotopic H NMR spectroscopy and kinetic studies verified that direct hydride transfer was the dominant pathway and rate-determining step of the CTH. Importantly, the Zr-FDCA-T microspheres could be recycled with no decrease in catalytic performance and little leaching of active sites. Moreover, good yields of C (i.e., furfural) or C products [i.e., maleic acid and 2(5H)-furanone] could be obtained from furfuryl alcohol without oxidation of the furan ring over these metal-FDCA hybrids. The content and ratio of Lewis-acid/base sites were demonstrated to dominantly affect the catalytic performance of these redox reactions.

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Section: Resultsmentioning

confidence: 67%

Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox Conversion of Biofuranics

Li¹,

Liu²,

Yang³

et al. 2017

ChemSusChem

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“…[15][16][17] One of the examples of these modulators used in the generation of defects in the structure is trifluoroacetic acid under synthesis conditions typically employing HCl. [15][16][17] One of the examples of these modulators used in the generation of defects in the structure is trifluoroacetic acid under synthesis conditions typically employing HCl.…”

Section: Synthesis Of Uio-66mentioning

confidence: 99%

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

et al. 2019

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frameworks (MOFs) are currently attracting considerable attention as heterogeneous catalysts at moderate temperatures, mainly for liquid-phase reactions. Since structural stability is one of the major concerns for the use of MOFs in catalysis, particularly considering that frequently some of the reported MOF materials are very unstable, the interest in this area has been focused on those MOFs exhibiting the highest structural robustness, UiO-66 being among the most widely used. Two introductory sections deal with the synthesis, structure and main properties of UiO-66, including its remarkable thermal (up to 350°C) and chemical (aqueous solution in a wide pH range) stability. The main body of the review summarizes those examples of using UiO-66 in catalysis grouped according to the nature of the active sites, starting with the use of UiO-66 as Lewis acids. In this section, emphasis has been made in the recent strategies to create structural defects in a controlled way that generate Lewis acidity. Other sections cover examples illustrating substituted terephthalate as active sites and the evidence that there is a synergy between acid and basic sites in close proximity that make some of these UiO-66 with substituents at the linker to act as dual acid-base catalysts. Other sections are focused on the use of UiO-66 as hosts of metal nanoparticles, metal oxides and other host, remarking the influence that the nature of UiO-66 and the possible presence of substituents in the framework play on the activity of the incorporated guest. The last section summarizes the current state of the art in the use of UiO-66 in catalysis and provides our views on future developments regarding the application of UiO-66 in industrial processes.

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“…26,27 The kinetic inertness of the metal-oxygen bonds means that coordination modulationthe addition of competing monotopic ligands to syntheses -is commonplace to enhance their self-assembly and materials properties, but it is usually done so in a trial and error approach. [28][29][30] The modulating agent inuences the crystallisation kinetics, most likely by competing with the ligands for attachment to the metal clusters as they assemble in solution. Utilising modulators in MOF syntheses can result in the creation of defects, in the form of missing linkers and/or clusters with concomitant incorporation of capping modulators, which can impart the MOF with interesting and unusual physical properties.…”

Section: -16mentioning

confidence: 99%

“…The additional peaks observed in the PXRD of 1-AA, the extra mass loss observed by TGA and the presence of residual acetate in its 1 H NMR spectrum, allied with the fact that acetic acid is wellknown to create defects in other early transition metal containing MOFs, infers that 1-AA contains a high concentration of acetate-capped defect sites. 30,51 Altering the number of equivalents of acetic acid added to syntheses of 1 (ESI, Fig. S10 †) showed that mesoporosity (and these defects) occurs when 30 or more equivalents of AA are used, but 60 equivalents retards MOF formation.…”

Section: Synthesis and Modulation Ofmentioning

confidence: 99%

Controlling interpenetration through linker conformation in the modulated synthesis of Sc metal–organic frameworks

et al. 2018

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Interpenetration in metal-organic frameworks (MOFs), where multiple nets of metal ions or clusters linked by organic ligands are nested within each other's pore spaces, affects important physical properties such as stability and gas uptake, and can be controlled through ligand sterics and modifying synthetic conditions. Herein, we extend the use of coordination modulation -deliberate addition of competing monotopic ligands to syntheses -to prepare Sc MOFs containing related biphenyl-4,4 0 -dicarboxylate (bpdc) and 2,2 0 -bipyridine-5,5 0 -dicarboxylate (bpydc) linkers. The Sc-bpdc MOF adopts a two-fold interpenetrated structure, however, the Sc-bpydc MOF is non-interpenetrated, despite only minor electronic modifications to the ligand. A comprehensive experimental and theoretical examination reveals that ligand twisting (energetically favourable for bpdc but not bpydc) and associated p-stacking interactions are a prerequisite for interpenetration. The more rigid Sc-bpdc is susceptible to modulation, resulting in differences in morphology, thermal stability and the synthesis of a highly defective, acetate-capped mesoporous material, while the large pore volume of Sc-bpydc allows postsynthetic metallation with CuCl 2 in a single-crystal to single-crystal manner. Controlling interpenetration through linker conformation could result in design of new materials with desirable properties such as bifunctional solidstate catalysts.

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Defect Engineering: Tuning the Porosity and Composition of the Metal–Organic Framework UiO-66 via Modulated Synthesis

Cited by 1,086 publications

References 94 publications

Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox Conversion of Biofuranics

Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox Conversion of Biofuranics

Engineering UiO‐66 Metal Organic Framework for Heterogeneous Catalysis

Controlling interpenetration through linker conformation in the modulated synthesis of Sc metal–organic frameworks

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