I15-1-X-ray Pair Distribution Function (XPDF)
I20-EDE-Energy Dispersive EXAFS (EDE)
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Diamond Proposal Number(s):
[30676, 30178]
Abstract: Zeolitic imidazolate frameworks (ZIFs), a subclass of metal–organic frameworks (MOFs), combine high porosity and chemical tunability with a resistance to harsh conditions. Understanding their response to extreme pressure and heat is critical for application development due to the conditions under which they may be required to work or for predicting their response to any processing before use. In this study, we characterize long- and short-range order in ZIF-8 and ZIF-62 under compression using Bragg X-ray diffraction and pair distribution function (PDF) analysis for a large pressure range (up to ∼5 GPa) previously attempted in very few works. X-ray absorption fine structure analysis was carried out under high-pressure-temperature conditions to probe the medium-range order, a novelty in MOFs. ZIF-8 demonstrated a crystalline–crystalline phase transition above 0.36 GPa but no full amorphization. In ZIF-62, pore intrusion of the silicone oil pressure-transmitting medium (PTM) was observed through negative compressibility and by retention of its open-pore configuration. Full amorphization was achieved, with heating lowering the amorphization threshold. Finally, a unique distortion in both MOFs was suggested by the spectroscopic data. These results provide insight into the thermomechanical stability of crystalline ZIFs and the mechanism underlying their amorphization.
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Dec 2025
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Open Access
Abstract: Understanding the relationship between crystal structure, bonding and thermal transport is critical for the discovery of materials with ultralow thermal conductivities. Materials in the bismuthinite–aikinite series, Cu1–x□xPb1–xBi1+xS3 (0 ≤ x ≤ 1), in which a Bi3+ cation and a vacancy (□) are progressively substituted by a Pb2+ and a Cu+ cation, exhibit ultralow thermal conductivities (∼0.5 W m−1K–1 for x < 1). Here, we investigate the effect of decreasing the Pb2+ and Cu+ content on the crystal structure and properties of Cu1–x□xPb1–xBi1+xS3 (x = 0, 0.33, 0.6 and 0.83). These materials exhibit two-channel thermal transport, with non-propagating phonons being the dominant contribution. Neutron diffraction data reveal that intermediate compositions crystallize in the krupkaite structure (x = 0.5, P21ma), instead of the end-member aikinite structure (x = 0, Pnma). Pair distribution function (PDF) analysis reveals that the disordering of vacancies and cations deviates significantly from that expected for a statistical distribution and that, at a local level, copper-rich and copper-poor regions occur. Reducing the Pb2+ and Cu+ content results in lattice softening, which may be attributed to the increased concentration of vacancies in copper-poor regions. Moreover, the persistence of short Pb2+–Cu+ distances in the copper-rich regions is likely to facilitate the cooperative interaction between lone pairs and rattling Cu+ cations that leads to phonon scattering. These findings provide crucial insights into the effect of the local structure on the phonon transport and highlight the potential of local-structure design to achieve high thermoelectric performance in crystalline solids.
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Oct 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Adam F.
Sapnik
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Philip A.
Chater
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Dean S.
Keeble
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John S. O.
Evans
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Federica
Bertolotti
,
Antonietta
Guagliardi
,
Lise J.
Støckler
,
Elodie A.
Harbourne
,
Anders B.
Borup
,
Rebecca S.
Silberg
,
Adrien
Descamps
,
Clemens
Prescher
,
Benjamin D.
Klee
,
Axel
Phelipeau
,
Imran
Ullah
,
Kárel G.
Medina
,
Tobias A.
Bird
,
Viktoria
Kaznelson
,
William
Lynn
,
Andrew L.
Goodwin
,
Bo B.
Iversen
,
Celine
Crepisson
,
Emil S.
Bozin
,
Kirsten M. Ø.
Jensen
,
Emma E.
Mcbride
,
Reinhard B.
Neder
,
Ian
Robinson
,
Justin S.
Wark
,
Michał
Andrzejewski
,
Ulrike
Boesenberg
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Erik
Brambrink
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Carolina
Camarda
,
Valerio
Cerantola
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Sebastian
Goede
,
Hauke
Höppner
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Oliver S.
Humphries
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Zuzana
Konopkova
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Naresh
Kujala
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Thomas
Michelat
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Motoaki
Nakatsutsumi
,
Alexander
Pelka
,
Thomas R.
Preston
,
Lisa
Randolph
,
Michael
Roeper
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Andreas
Schmidt
,
Cornelius
Strohm
,
Minxue
Tang
,
Peter
Talkovski
,
Ulf
Zastrau
,
Karen
Appel
,
David A.
Keen
Diamond Proposal Number(s):
[39017]
Open Access
Abstract: High-quality total scattering data, a key tool for understanding atomic-scale structure in disordered materials, require stable instrumentation and access to high momentum transfers. This is now routine at dedicated synchrotron instrumentation using high-energy X-ray beams, but it is very challenging to measure a total scattering dataset in less than a few microseconds. This limits their effectiveness for capturing structural changes that occur at the much faster timescales of atomic motion. Current X-ray free-electron lasers (XFELs) provide femtosecond-pulsed X-ray beams with maximum energies of ∼24 keV, giving the potential to measure total scattering and the attendant pair distribution functions (PDFs) on femtosecond timescales. We demonstrate that this potential has been realized using the HED scientific instrument at the European XFEL and present normalized total scattering data for 0.35 Å−1 < Q < 16.6 Å−1 and their PDFs from a broad spectrum of materials, including crystalline, nanocrystalline and amorphous solids, liquids and clusters in solution. We analyzed the data using a variety of methods, including Rietveld refinement, small-box PDF refinement, joint reciprocal–real-space refinement, cluster refinement and Debye scattering analysis. The resolution function of the setup is also characterized. We conclusively show that high-quality data can be obtained from a single ∼30 fs XFEL pulse for multiple different sample types. Our efforts not only significantly increase the existing maximum reported Q range for an S(Q) measured at an XFEL but also mean that XFELs are now a viable X-ray source for the broad community of people using reciprocal-space total scattering and PDF methods in their research.
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Sep 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Chumei
Ye
,
Lauren N.
Mchugh
,
Pierre
Florian
,
Ruohan
Yu
,
Celia
Castillo-Blas
,
Celia
Chen
,
Arad
Lang
,
Yuhang
Dai
,
Jingwei
Hou
,
David A.
Keen
,
Sian E.
Dutton
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[35405]
Open Access
Abstract: Hybrid organic-inorganic perovskites (HOIPs) have garnered significant attention for their crystalline properties, yet recent findings reveal that they can also form liquid and glassy phases, offering an alternative platform for understanding non-crystalline materials. In this study, we present a detailed investigation into the structural dynamics of the melting and glass formation process of a two-dimensional (2D) HOIP, (S−(−)−1-(1−naphthyl)ethylammonium)2PbBr4. Compared to its crystalline counterpart, the glass exhibits superior mechanical properties, including higher Young’s modulus and hardness. Our structural studies reveal that the liquid and glass formed from the 2D HOIP exhibit network-forming behaviour, featuring limited short-range order within individual octahedra, partial retention of metal-halide-metal connectivity between neighbouring octahedra, and residual structural correlations mediated by organic cations. We then combine in situ variable-temperature X-ray total scattering experiments, terahertz far-infrared absorption spectroscopy and solid-state nuclear magnetic resonance techniques to study the melting mechanism and the nature of the HOIP liquid obtained. Our results deepen the understanding of the structural evolution and property relationships in HOIP glasses, providing a foundation for their potential applications in advanced phase-change material technologies.
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Aug 2025
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I11-High Resolution Powder Diffraction
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George S.
Phillips
,
James M. A.
Steele
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Farheen N.
Sayed
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Leonhard
Karger
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Liam A. V.
Nagle-Cocco
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Annalena R.
Genreith-Schriever
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Gabriel E.
Perez
,
David A.
Keen
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Jürgen
Janek
,
Torsten
Brezesinski
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Joshua D.
Bocarsly
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Sian E.
Dutton
,
Clare P.
Grey
Diamond Proposal Number(s):
[34243]
Open Access
Abstract: Lithium nickel oxide, LiNiO2 (LNO), and its doped derivatives are promising battery cathode materials with high gravimetric capacity and operating voltages. They are also of interest to the field of quantum magnetism due to the presumed S = 1/2 triangular lattice and associated geometric frustration. However, the tendency for Li/Ni substitutional defects and off-stoichiometry makes fundamental studies challenging. In particular, there is still a discrepancy between the rhombohedral (R3̅m) bulk structure and the Jahn–Teller (JT) distortions of the NiO6 octahedra inferred on the basis of local structural probes. Karger et al. (Chem. Mater. 2023, 35, 648–657) recently used Na/Li ion exchange to synthesize “defect-free” LNO by exploiting the absence of antisite disorder in NaNiO2 (NNO). Here we characterize the short- and long-range structure of this ion-exchanged material and observe splittings of key Bragg reflections at 100 K in X-ray and neutron diffraction (XRD and NPD), indicative of a monoclinic distortion induced by a cooperative collinear JT distortion, similar to that seen in NNO. Variable temperature XRD reveals a second-order phase transition from the monoclinic (C2/m) low-temperature structure to a rhombohedral (R3̅m) structure above ∼400 K. We propose that this collinear JT ordering is also present in solid-state synthesized LNO with the domain size and extent of monoclinic distortion controlled by defect concentration. This new structural description of LNO will help advance our understanding of its electronic and magnetic properties and the series of phase transformations that this material undergoes upon electrochemical cycling in Li-ion batteries.
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Jul 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[29957]
Open Access
Abstract: The development of metal-organic framework (MOF) crystal-glass composites (CGCs) has been hindered by the scarcity of MOF glass matrices with low glass transition temperatures (Tgs). Here, we investigate a CGC consisting of a low-Tg MOF glass, (agZIF-UC-7) and UiO-66. Powder X-ray diffraction and stability tests in phosphate buffer saline solution showed UiO-66 was stabilised in the glass matrix. Additionally, the composite exhibited enhanced dye uptake and gas adsorption relative to agZIF-UC-7.
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Jul 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[29957]
Open Access
Abstract: We report the solvent-free synthesis of a crystalline heterometallic imidazolate derivative with formula [Fe1Zn2(im)6(Him)2], designated MUV-25, incorporating both iron and zinc. The structure imposes strict positional constraints on the metal centres due to the lattice containing distinct geometric coordination sites, tetrahedral and octahedral. As a consequence, each metal is exclusively directed to its specific coordination site, ensuring precise spatial organization within the lattice. Atom locations were meticulously monitored utilizing X-ray diffraction (single crystal and total scattering) and XAS techniques, demonstrating that the tetrahedral sites are occupied exclusively by zinc, and the octahedral sites are occupied by iron. This combination of metal centres results, upon heating, in a structural phase transformation to the zni topology at a very low temperature. Further heating causes the melting of the solid, yielding a heterometallic MOF-derived glass. The methodology lays the groundwork for tailoring crystalline structures to advance the development of novel materials capable of melting and forming glasses upon cooling.
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Mar 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Celia
Castillo-Blas
,
Montaña J.
García
,
Ashleigh M.
Chester
,
Matjaž
Mazaj
,
Shaoliang
Guan
,
Georgina P.
Robertson
,
Ayano
Kono
,
James M. A.
Steele
,
Luis
León-Alcaide
,
Bruno
Poletto-Rodrigues
,
Philip A.
Chater
,
Silvia
Cabrera
,
Andraž
Krajnc
,
Lothar
Wondraczek
,
David A.
Keen
,
Jose
Alemán
,
Thomas
Bennett
Diamond Proposal Number(s):
[29957]
Open Access
Abstract: Metal–organic framework (MOF) composites are proposed as solutions to the mechanical instability of pure MOF materials. Here, we present a new compositional series of recently discovered MOF–crystalline inorganic glass composites. In this case, formed by the combination of a photocatalytic titanium MOF (MIL-125-NH2) and a phosphate-based glass (20%Na2O–10%Na2SO4–70%P2O5). This new family of composites has been synthesized and characterized using powder X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and X-ray total scattering. Through analysis of the pair distribution function extracted from X-ray total scattering data, the atom–atom interactions at the MOF–glass interface are described. Nitrogen and carbon dioxide isotherms demonstrate good surface area values despite the pelletization and mixing of the MOF with a dense inorganic glass. The catalytic activity of these materials was investigated in the photooxidation of amines to imines, showing the retention of the photocatalytic effectiveness of the parent pristine MOF.
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Mar 2025
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Emily V.
Shaw
,
Celia
Castillo Blas
,
Timothy
Lambden
,
Beatriz
De Santos
,
Bethan
Turner
,
Giulio I.
Lampronti
,
Joonatan E. M.
Laulainen
,
Georgina
Robertson
,
Ashleigh M.
Chester
,
Chumei
Ye
,
Shaoliang
Guan
,
Joshua
Karlsson
,
Valentina
Martinez
,
Ivana
Brekalo
,
Bahar
Karadeniz
,
Silvia
Cabrera
,
Lauren N.
Mchugh
,
Krunoslav
Užarević
,
Jose
Aleman
,
Alberto
Fraile
,
Rachel C
Evans
,
Paul
Midgley
,
David A.
Keen
,
Xavier
Moya
,
Thomas D.
Bennett
Open Access
Abstract: In this work, we investigated the response of the metal-organic framework MIL-125-NH2 to ball-milling. Both localised and bulk analyses revealed that prolongued ball-milling results in a complete loss of long-range structural order. Investigation of this disorder revealed partial retention of the local bonding of the secondary building unit, suggesting structure collapse progressed primarily through metal-linker bond breakage. We explored the photocatalytic performance of the materials, and examined the materials’ band gap using UV-Vis reflectance spectroscopy.
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Feb 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Shichun
Li
,
Chao
Ma
,
Jingwei
Hou
,
Shuwen
Yu
,
Aibing
Chen
,
Juan
Du
,
Philip A.
Chater
,
Dean S.
Keeble
,
Zhihua
Qiao
,
Chongli
Zhong
,
David A.
Keen
,
Yu
Liu
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Crystalline metal-organic frameworks (MOFs) exhibit enormous potential application in gas separation, thanks to their highly porous structures and precise pore size distributions. Nevertheless, the inherent limitations in mechanical stability of crystalline MOFs cause challenges in processing MOF powders into bulky structures, particularly for membrane filtrations. Melt-quenched MOF glasses boast excellent processability due to liquid-like properties. However, the melting process diminishes the inherent porosity, leading to reduced gas adsorption capacities and lower gas diffusion coefficients. In this work, we demonstrated that enhancing the porosity of MOF glasses is achievable through topological engineering on the crystalline precursors. Crystalline zeolitic imidazolate frameworks (ZIFs) with large 12-membered rings pores, including AFI and CAN topology, were synthesized by using both structure-directing agents and mixed organic ligands. The large pores are partially preserved in the melt-quenched glass as evidenced by high-pressure CO2 absorption at 3000 kPa. The agAFI-[Zn(Im)1.68(bIm)0.32] glass was then fabricated into self-supported membranes, which shows high gas separation performance, for example, CO2 permeance of 3.7 × 104 GPU with a CO2/N2 selectivity of 14.8.
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Feb 2025
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