B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Boya
Tang
,
David
Brooks
,
Meng
He
,
Yinlin
Chen
,
Zhaozhao
Hu
,
Xue
Han
,
Jiangnan
Li
,
Siyu
Zhao
,
Jiarui
Fan
,
Yukun
Ye
,
Ivan
Da Silva
,
Cheng
Li
,
Zi
Wang
,
Lutong
Shan
,
Bing
Han
,
Weiyao
Li
,
Daniil
Polyukhov
,
Bing
An
,
Catherine
Dejoie
,
Martin
Wilding
,
Shaojun
Xu
,
Meredydd
Kippax-Jones
,
Zhaodong
Zhu
,
Yujie
Ma
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Mark D.
Frogley
,
Louise S.
Natrajan
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[37900, 37887, 36450]
Abstract: Photocatalytic synthesis of hydrogen peroxide (H2O2) from oxygen (O2) is a challenging process. Metal–organic framework (MOF) materials are emerging photocatalysts with potential tunable light absorption properties. Herein, we report a rhenium (Re) modified Zr-based MOF, Re10-MFM-67, in which active Re sites are incorporated into MFM-67 by partial replacement of 9,9′-bianthracene-10,10′-dicarboxylic acid (H2L1) with a [(H2L2)ReI(CO)3Cl] (H2L2 = 2,2′-bipyridine-5,5′-dicarboxylic acid) moiety. Re10-MFM-67 (10 refers to the molar percentage content of Re complex within the material) exhibits broadband light absorption with an exceptional rate of formation of H2O2 from O2 of 8.50 mmol gcat–1 h–1 and a record turnover frequency (TOF) of 28.7 h–1 under visible light irradiation (λ > 400 nm). Synchrotron powder X-ray diffraction (SPXRD) and neutron powder diffraction (NPD) confirm the structure of Re10-MFM-67, and together with extended X-ray absorption fine structure (EXAFS) analysis establish the coordination environment and binding of the [ReI(CO)3Cl] moiety within the framework structure. In situ electron paramagnetic resonance (EPR) spectroscopy suggests that photocatalytic H2O2 generation on Re10-MFM-67 occurs via a two-step oxygen reduction reaction (ORR) pathway with the superoxide anion formed as an intermediate. This study promotes the design of MOF-based photocatalysts with conjugated ligands for efficient photosynthesis.
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Jul 2025
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I11-High Resolution Powder Diffraction
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Open Access
Abstract: This work presents the synthesis and characterization of a new neutral mononuclear Fe(II) spin transition (ST) complex, [FeII(L)2]0 (4Cl), where L is an asymmetrically substituted tridentate ligand 2-(3-(4-chlorophenyl)-(1H-1,2,4-triazol-5-yl)-6-(1H-pyrazol-1-yl)pyridine. 4Cl exhibits a remarkably wide stable ST hysteresis loop ca. 60 K wide embracing room temperature (T1/2↑ = 308 K and T1/2↓ = 248 K). Detailed structural, calorimetric and spectroscopic investigations, including X-ray diffraction with Rietveld analysis, Raman spectroscopy, and photoluminescence, reveal the crucial role of subtle structural changes within the crystal lattice in driving the cooperative spin transition. The DFT energy framework analysis highlights the interplay of balanced stabilizing and destabilizing intermolecular interactions that contribute to the observed hysteresis. Furthermore, the fluorescent properties of 4Cl exhibit distinct changes in emission intensity and wavelength upon spin state switching with emission color change from sky blue in the high spin state to violet in the low spin state. The compound is the first example of the spin transition compound with bistable fluorescence response at room temperature.
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Jun 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
I14-Hard X-ray Nanoprobe
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Lotfi
Boudjema
,
Anil Kumar
Dahiya
,
Ivan
Da Silva
,
Diego
Gianolio
,
Izuchika
Nduka
,
Manfred Erwin
Schuster
,
Gea T.
Van De Kerkhof
,
Paulina
Kalinowska
,
Emilio
Borrego-Marin
,
Jorge A. R.
Navarro
,
Valentina
Colombo
,
June
Mccorquodale
,
David C.
Grinter
,
Pilar
Ferrer
,
Georg
Held
,
C. Richard A.
Catlow
,
Rosa
Arrigo
Diamond Proposal Number(s):
[28630]
Open Access
Abstract: We investigate the rapid microwave-assisted solvothermal synthesis of a Cu-MOF (Metal-Organic Framework) with open metal sites, with a focus on understanding its CO2 capture properties in relation to phase purity and stability. A combined experimental and theoretical approach is used to identify the MOF structural features involved in the adsorption process. Specifically, Cu(I) defects are found playing an important role in the CO2 adsorption process, with the Cu-1 sample, synthesized using an optimized ligand/Cu precursor ratio for highest phase purity, exhibiting more abundant Cu(I) defects as well as highest adsorption capacity. Grand Canonical Monte Carlo simulations show that the Cu(I) sites exhibit a greater affinity for CO2 adsorption compared to the Cu(II) sites. In situ spectroscopic soft and hard X-ray absorption fine structure spectroscopy confirm the conversion of Cu(I) to Cu(II) upon CO2 chemisorption, with this conversion being more pronounced in the core of the particles. The simulations are used to estimate the fraction of Cu(I) defects and Cu(II) sites present within the Cu-1 MOF and to validate the experimental isotherm. Overall, this study provides insights into the CO2 capture properties of GIF-KUC Cu-MOFs and highlights the importance of phase purity for achieving high adsorption performance.
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Jun 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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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[32893]
Open Access
Abstract: Reversible lithium intercalation into the van der Waals phase V2Te2O, forming new phases LixV2Te2O with x approaching 2, is reported using both chemical and electrochemical methods. The progress of each reaction was followed using powder X-ray diffraction and the crystal structure of the intercalated phase with x = 1, LiV2Te2O, was refined using powder neutron diffraction. The intercalated Li ions occupy vacant pseudo-octahedral sites and the unit cell expands on reduction with no change in symmetry. The lithium ions can be removed chemically or electrochemically, making this the first known oxytelluride to undergo reversible lithium intercalation.
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Feb 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[33639, 34919, 36558]
Open Access
Abstract: Spinel ferrites exhibit significant promise in photocatalysis and other applications due to their compositional diversity and favourable electronic structure, magnetism, and partially tuneable cation distribution. However, their complex properties, for example, the different behaviour of bulk and nanostructured materials, are not well understood. Here, we combine advanced computational and experimental methods with reactivity measurements to explore the inversion degrees, electronic structures, and photocatalytic activities of MFe2O4 spinels (M = Co, Cu, Zn). X-ray diffraction and anomalous X-ray scattering measurements determined bulk inversion degrees of 0.81, 0.91, and 0.26 for CoFe2O4, CuFe2O4, and ZnFe2O4, respectively. Photocatalytic tests showed that only ZnFe2O4 is active in the oxygen evolution reaction (OER), which correlates with its favourable band alignment, as determined through electronic structure simulations. Surface-sensitive X-ray Absorption Spectroscopy (XAS) measurements provided insights into the cation distributions at the surfaces, showing significant deviations from bulk properties, particularly in ZnFe2O4 in which 52% of the near-surface tetrahedral sites are occupied by Fe cations, compared to 26% in the bulk. DFT simulations of ZnFe2O4 illustrated how the surface terminations can alter the thermodynamic preference for cation distribution in comparison with the bulk. Our findings illustrate the complex interplay between surface and bulk properties in spinel ferrites.
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Sep 2024
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I11-High Resolution Powder Diffraction
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Martin
Schroeder
,
Christopher
Marsh
,
Xue
Han
,
Zhenzhong
Lu
,
Ivan
Da Silva
,
Yongqiang
Chen
,
Luke L.
Daemen
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Anibal Javier
Ramirez-Cuesta
,
Sihai
Yang
Open Access
Abstract: The functionalisation of organic linkers in metal-organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible –COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO2 and C2H2 molecules to the free -COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO2 and C2H2 with a high selectivity for C2H2 over C2H4. In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO2 and C2H2 molecules with free -COOH and -OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.
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Apr 2024
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B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[22137, 30398]
Open Access
Abstract: Metal–organic framework (MOF) materials are attracting increasing interest in the field of electronics due to their structural diversity, intrinsic porosity, and designable host–guest interactions. Here, we report the dielectric properties of a series of robust materials, MFM-300(M) (M = Al, Sc, Cr, Fe, Ga, In), when exposed to different guest molecules. MFM-300(Fe) exhibits the most notable increase in dielectric constant to 35.3 ± 0.3 at 10 kHz upon adsorption of NH3. Structural analysis suggests that the electron delocalization induced by host–guest interactions between NH3 and the MOF host, as confirmed by neutron powder diffraction studies, leads to structural polarization, resulting in a high dielectric constant for NH3@MFM-300(Fe). This is further supported by ligand-to-metal charge-transfer transitions observed by solid-state UV/vis spectroscopy. The high detection sensitivity and stability to NH3 suggest that MFM-300(Fe) may act as a powerful dielectric-based sensor for NH3.
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Oct 2023
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B18-Core EXAFS
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Yujie
Ma
,
Xue
Han
,
Shaojun
Xu
,
Zhe
Li
,
Wanpeng
Lu
,
Bing
An
,
Daniel
Lee
,
Sarayute
Chansai
,
Alena M.
Sheveleva
,
Zi
Wang
,
Yinlin
Chen
,
Jiangnan
Li
,
Weiyao
Li
,
Rongsheng
Cai
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Lewis
Hughes
,
Pascal
Manuel
,
Anibal J.
Ramirez-Cuesta
,
Sarah J.
Haigh
,
Christopher
Hardacre
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[19850]
Open Access
Abstract: Conversion of methane (CH4) to ethylene (C2H4) and/or acetylene (C2H2) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH4 controllably, and separating C2+ products from unreacted CH4 can be challenging. Here, we report the direct conversion of CH4 to C2H4 and C2H2 driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal–organic framework material, MFM-300(Fe). The selectivity for the formation of C2H4 and C2H2 reaches 96% with a high time yield of 334 μmol gcat–1 h–1. At a conversion of 10%, the selectivity to C2+ hydrocarbons and time yield exceed 98% and 2056 μmol gcat–1 h–1, respectively, representing a new benchmark for conversion of CH4. In situ neutron powder diffraction, inelastic neutron scattering and solid-state nuclear magnetic resonance, electron paramagnetic resonance (EPR), and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modeling studies, reveal the crucial role of Fe–O(H)–Fe sites in activating CH4 and stabilizing reaction intermediates via the formation of an Fe–O(CH3)–Fe adduct. In addition, a cascade fixed-bed system has been developed to achieve online separation of C2H4 and C2H2 from unreacted CH4 for direct use. Integrating the processes of CH4 activation, conversion, and product separation within one system opens a new avenue for natural gas utility, bridging the gap between fundamental studies and practical applications in this area.
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Sep 2023
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I11-High Resolution Powder Diffraction
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Michael F.
Thorne
,
Celia
Castillo Blas
,
Lauren N.
Mchugh
,
Alice M.
Bumstead
,
Georgina
Robertson
,
Adam F.
Sapnik
,
Chloe S.
Coates
,
Farheen N.
Sayed
,
Clare P.
Grey
,
David A.
Keen
,
Martin
Etter
,
Ivan
Da Silva
,
Krunoslav
Užarević
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[28349]
Open Access
Abstract: The structure of a new ZIF-8 polymorph with quartz topology (qtz) is reported. This qtz-[Zn(mIm)2] phase was obtained by mechanically amorphising crystalline ZIF-8, before heating the resultant amorphous phase to between 282 and 316 °C. The high temperature phase structure was obtained from X-ray powder diffraction, and its thermal behaviour, CO2 gas sorption properties and dye adsorption ability were investigated.
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Sep 2022
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