I15-1-X-ray Pair Distribution Function (XPDF)
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Bikash Kumar
Shaw
,
Ashlea R.
Hughes
,
Maxime
Ducamp
,
Stephen
Moss
,
Anup
Debnath
,
Adam F.
Sapnik
,
Michael F.
Thorne
,
Lauren N.
Mchugh
,
Andrea
Pugliese
,
Dean S.
Keeble
,
Philip
Chater
,
Juan M.
Bermudez-Garcia
,
Xavier
Moya
,
Shyamal K.
Saha
,
David A.
Keen
,
François-Xavier
Coudert
,
Frédéric
Blanc
,
Thomas
Bennett
Diamond Proposal Number(s):
[20038]
Abstract: Several organic–inorganic hybrid materials from the metal–organic framework (MOF) family have been shown to form stable liquids at high temperatures. Quenching then results in the formation of melt-quenched MOF glasses that retain the three-dimensional coordination bonding of the crystalline phase. These hybrid glasses have intriguing properties and could find practical applications, yet the melt-quench phenomenon has so far remained limited to a few MOF structures. Here we turn to hybrid organic–inorganic perovskites—which occupy a prominent position within materials chemistry owing to their functional properties such as ion transport, photoconductivity, ferroelectricity and multiferroicity—and show that a series of dicyanamide-based hybrid organic–inorganic perovskites undergo melting. Our combined experimental–computational approach demonstrates that, on quenching, they form glasses that largely retain their solid-state inorganic–organic connectivity. The resulting materials show very low thermal conductivities (~0.2 W m−1 K−1), moderate electrical conductivities (10−3–10−5 S m−1) and polymer-like thermomechanical properties.
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May 2021
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E02-JEM ARM 300CF
I15-1-X-ray Pair Distribution Function (XPDF)
I22-Small angle scattering & Diffraction
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Adam F.
Sapnik
,
Irene
Bechis
,
Sean M.
Collins
,
Duncan N.
Johnstone
,
Giorgio
Divitini
,
Andrew J.
Smith
,
Philip A.
Chater
,
Matthew A.
Addicoat
,
Timothy
Johnson
,
David A.
Keen
,
Kim E.
Jelfs
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038, 24563]
Open Access
Abstract: Amorphous metal–organic frameworks (MOFs) are an emerging class of materials. However, their structural characterisation represents a significant challenge. Fe-BTC, and the commercial equivalent Basolite® F300, are MOFs with incredibly diverse catalytic ability, yet their disordered structures remain poorly understood. Here, we use advanced electron microscopy to identify a nanocomposite structure of Fe-BTC where nanocrystalline domains are embedded within an amorphous matrix, whilst synchrotron total scattering measurements reveal the extent of local atomic order within Fe-BTC. We use a polymerisation-based algorithm to generate an atomistic structure for Fe-BTC, the first example of this methodology applied to the amorphous MOF field outside the well-studied zeolitic imidazolate framework family. This demonstrates the applicability of this computational approach towards the modelling of other amorphous MOF systems with potential generality towards all MOF chemistries and connectivities. We find that the structures of Fe-BTC and Basolite® F300 can be represented by models containing a mixture of short- and medium-range order with a greater proportion of medium-range order in Basolite® F300 than in Fe-BTC. We conclude by discussing how our approach may allow for high-throughput computational discovery of functional, amorphous MOFs.
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Apr 2021
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E02-JEM ARM 300CF
I15-1-X-ray Pair Distribution Function (XPDF)
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Adam F.
Sapnik
,
Duncan N.
Johnstone
,
Sean M.
Collins
,
Giorgio
Divitini
,
Alice M.
Bumstead
,
Christopher W.
Ashling
,
Philip A.
Chater
,
Dean S.
Keeble
,
Timothy
Johnson
,
David A.
Keen
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038, 20198]
Open Access
Abstract: Defect engineering is a powerful tool that can be used to tailor the properties of metal–organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal–linker bonds, generating additional coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially retained, even in the amorphised material. We find that solvents can be used to stabilise the MIL-100 (Fe) framework against collapse, which leads to a substantial retention of porosity over the non-stabilised material.
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Mar 2021
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[25186]
Abstract: We present a structural and magnetic study of two batches of polycrystalline LiNi0.8Mn0.1Co0.1O2 (commonly known as Li NMC 811), a Ni-rich Li ion battery cathode material, using elemental analysis, X-ray and neutron diffraction, magnetometry, and polarized neutron scattering measurements. We find that the samples, labeled S1 and S2, have the composition Li1–xNi0.9+x–yMnyCo0.1O2, with x = 0.025(2), y = 0.120(2) for S1 and x = 0.002(2), y = 0.094(2) for S2, corresponding to different concentrations of magnetic ions and excess Ni2+ in the Li+ layers. Both samples show a peak in the zero-field-cooled (ZFC) dc susceptibility at 8.0(2) K, but the temperature at which the ZFC and FC (field-cooled) curves deviate is substantially different: 64(2) K for S1 and 122(2) K for S2. The ac susceptibility measurements show that the transition for S1 shifts with frequency whereas no such shift is observed for S2 within the resolution of our measurements. Our results demonstrate the sample dependence of magnetic properties in Li NMC 811, consistent with previous reports on the parent material LiNiO2. We further establish that a combination of experimental techniques is necessary to accurately determine the chemical composition of next-generation battery materials with multiple cations.
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Dec 2020
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I15-1-X-ray Pair Distribution Function (XPDF)
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Louis
Longley
,
Courtney
Calahoo
,
René
Limbach
,
Yang
Xia
,
Joshua M.
Tuffnell
,
Adam F.
Sapnik
,
Michael F.
Thorne
,
Dean S.
Keeble
,
David A.
Keen
,
Lothar
Wondraczek
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Metal-organic framework (MOF) glasses have become a subject of interest as a distinct category of melt quenched glass, and have potential applications in areas such as ion transport and sensing. In this paper we show how MOF glasses can be combined with inorganic glasses in order to fabricate a new family of materials composed of both MOF and inorganic glass domains. We use an array of experimental techniques to propose the bonding between inorganic and MOF domains, and show that the composites produced are more mechanically pliant than the inorganic glass itself.
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Nov 2020
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E02-JEM ARM 300CF
I15-1-X-ray Pair Distribution Function (XPDF)
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Shichun
Li
,
Shuwen
Yu
,
Sean M.
Collins
,
Duncan N.
Johnstone
,
Christopher W.
Ashling
,
Adam F.
Sapnik
,
Philip A.
Chater
,
Dean S.
Keeble
,
Lauren N.
Mchugh
,
Paul A.
Midgley
,
David A.
Keen
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038, 22632, 21979]
Open Access
Abstract: Metal–organic framework crystal–glass composite (MOF CGC) materials consist of a crystalline MOF embedded within a MOF–glass matrix. In this work, a new synthetic route to these materials is demonstrated through the preparation of two ZIF-62 glass-based CGCs, one with crystalline ZIF-67 and the other with crystalline UiO-66. Previous attempts to form these CGCs failed due to the high processing temperatures involved in heating above the melting point of ZIF-62. Annealing of the ZIF-62 glass above the glass transition with each MOF however leads to stable CGC formation at lower temperatures. The reduction in processing temperatures will enable the formation of a greatly expanded range of MOF CGCs.
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Sep 2020
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Recently, there has been growing interest in the amorphous states of metal–organic frameworks (MOFs). Particular focus has been given to melt-quenched MOF glasses. In this work, to improve our understanding of the factors influencing melting, the thermal response of four closely related zeolitic imidazolate frameworks (ZIFs) was studied. Electron withdrawing ligands were found to lower both the melting and glass transition temperatures, providing a promising strategy for improving the processability of MOFs in the liquid state. Crucially, dense frameworks appear to be essential for melting, with their presence also initiating the melting of open pore frameworks. This opens up the rich polymorphic landscape of ZIFs to the preparation of novel MOF liquids and glasses.
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May 2020
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I15-1-X-ray Pair Distribution Function (XPDF)
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Patrick
Hirschle
,
Christian
Hirschle
,
Konstantin
Böll
,
Markus
Döblinger
,
Miriam
Höhn
,
Joshua M.
Tuffnell
,
Christopher W.
Ashling
,
David
Keen
,
Thomas D.
Bennett
,
Joachim O.
Rädler
,
Ernst
Wagner
,
Michael
Peller
,
Ulrich
Lächelt
,
Stefan
Wuttke
Diamond Proposal Number(s):
[21260]
Abstract: Iron(III) fumarate materials are well suited for biomedical applications as they feature biocompatible building blocks, porosity, chemical functionalizability, and magnetic resonance imaging (MRI) activity. The synthesis of these materials however is difficult to control, and it has been challenging to produce monodisperse particle sizes and morphologies that are required in medical use. Here, we report the optimization of iron(III) fumarate nano- and microparticle synthesis by surfactant-free methods, including room temperature, solvothermal, microwave, and microfluidic conditions. Four variants of iron(III) fumarate with distinct morphologies were isolated and are characterized in detail. Structural characterization shows that all iron(III) fumarate variants exhibit the metal–organic framework (MOF) structure of MIL-88A. Nanoparticles with a diameter of 50 nm were produced, which contain crystalline areas not exceeding 5 nm. Solvent-dependent swelling of the crystalline particles was monitored using in situ X-ray diffraction. Cytotoxicity experiments showed that all iron(III) fumarate variants feature adequate biotolerability and no distinct interference with cellular metabolism at low concentrations. Magnetic resonance relaxivity studies using clinical MRI equipment, on the other hand, proved that the MRI contrast characteristics depend on particle size and morphology. All in all, this study demonstrates the possibility of tuning the morphological appearance of iron(III) fumarate particles and illustrates the importance of optimizing synthesis conditions for the development of new biomedical materials.
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Mar 2020
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I15-1-X-ray Pair Distribution Function (XPDF)
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Jingwei
Hou
,
María Laura
Ríos Gómez
,
Andraž
Krajnc
,
Aoife
Mccaul
,
Shichun
Li
,
Alice M.
Bumstead
,
Adam F.
Sapnik
,
Zeyu
Deng
,
Rijia
Lin
,
Philip A.
Chater
,
Dean S.
Keeble
,
David A.
Keen
,
Dominique
Appadoo
,
Bun
Chan
,
Vicki
Chen
,
Gregor
Mali
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Abstract: The synthesis of four novel crystalline zeolitic imidazolate framework (ZIF) structures using a mixed-ligand approach is reported. The inclusion of both imidazolate and halogenated benzimidazolate-derived linkers leads to glass-forming behavior by all four structures. Melting temperatures are observed to depend on both electronic and steric effects. Solid-state NMR and terahertz (THz)/Far-IR demonstrate the presence of a Zn-F bond for fluorinated ZIF glasses. In situ THz/Far-IR spectroscopic techniques reveal the dynamic structural properties of crystal, glass and liquid phases of the halogenated ZIFs, linking the melting behavior of ZIFs to the propensity of the ZnN4 tetrahedra to undergo thermally-induced deformation. The inclusion of halogenated ligands within MOF-glasses improves their gas uptake properties.
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Jan 2020
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E02-JEM ARM 300CF
I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[20038, 20195]
Abstract: Metal-organic framework crystal-glass composites (MOF-CGCs) are materials in which a crystalline MOF is dispersed within a MOF glass. In this work, we explore the room temperature stabilization of the open-pore form of MIL-53(Al), usually observed at high-temperature, which occurs upon encapsulation within a ZIF-62(Zn) MOF glass matrix. A series of MOF-CGCs containing different loadings of MIL-53(Al) were synthesized and characterized using X-ray diffraction and nuclear magnetic resonance spectroscopy. An upper limit of MIL-53(Al) that can be stabilized in the composite was determined for the first time. The nanostructure of the composites was probed using pair distribution function analysis and scanning transmission electron microscopy. Notably, the distribution and integrity of the crystalline compo-nent in a sample series was determined, and these findings related to the MOF-CGC gas adsorption capacity in order to identify the optimal loading necessary for maximum CO2 sorption capacity.
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Sep 2019
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