I22-Small angle scattering & Diffraction
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María Calles
García
,
Hugo
Salazar
,
Sylvia
Britto
,
Oleksandr
Tomchuk
,
Pedro M.
Martins
,
Arunava
Pradhan
,
Fernanda
Cássio
,
Senentxu Lanceros
Mendez
,
Koro
De La Caba
,
Pedro
Guerrero
,
Viktor
Petrenko
,
Roberto Fernández
De Luis
Diamond Proposal Number(s):
[42059]
Open Access
Abstract: Access to clean water in isolated regions remains a major challenge, particularly due to contamination by the five most prevalent heavy metals: Hg(II), Pb(II), Cd(II), As(III/V), and Cr(VI). Traditional sorbents are limited in their ability to capture all the “big five” heavy metals, since they occur as cationic, neutral, or anionic species under standard conditions. To address this challenge, we have integrated a thiol rich Zr(IV)- Metal-Organic Framework (MOF), namely BCM-1, into a soy protein (SPI) and chitin (CHI) sponge in order to engineer a 3D-hybrid water filter. The components and the composite systems were thoroughly characterised by conventional means. Additionally, neutron imaging was used to reveal the 3D-interconnected micro- to macroporous structure of the filters, while Small-Angle X-ray Scattering (SAXS) confirmed the presence of BCM-1 as monodisperse nanoparticles. The 3D-sponge combines mechanical stability, high permeability, and broad chemical affinity, allowing the efficient removal of all five heavy metals through simple adjustments of its activation conditions. Adsorption experiments demonstrated over 90 % removal for most target metals depending if the hybrid-sponge is employed as synthesised, or after activating at pH = 1. When tested with 1 ppm solutions, they exhibit adsorption efficiencies for Hg(II), Pb(II), Cd(II), As(V), and Cr(VI) of 60.8/100 %, 94.4/74.8 %, 15.7/69.1 %, 100/38.2 %, 5.7/100 %, and 13.5/97.4 %, before and after the activation of the 3D-sponge, respectively. The metrics are consistently maintained over three adsorption/desorption cycles in surface water samples. On the whole, this work provides a scalable and sustainable approach to combine biopolymers and MOFs for real-world water remediation applications and highlights the key role of their protonation state on their absorptive properties.
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Oct 2025
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B18-Core EXAFS
I14-Hard X-ray Nanoprobe
I18-Microfocus Spectroscopy
I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[33674, 35117, 35776, 40942, 37789]
Open Access
Abstract: Achieving safe and sustainable nanomaterials remains challenging—not necessarily from limited synthetic innovation but due to gaps in observing structural and chemical transformations under environmental conditions. Here, we make a call for a tri-beam operando characterization strategy, integrating synchrotron, neutron, and X-ray free-electron laser (XFEL) techniques into one synergistic experimental framework. Unlike traditional methods providing disconnected snapshots, tri-beam analysis dynamically tracks nanomaterial evolution from atomic-scale changes to structural collapse under near-real-world/quasi-realistic conditions. This holistic approach reveals previously hidden degradation pathways, transient states, and physicochemical thresholds that reshape definitions of material safety. Enhanced by robotic automation, machine learning, and findable, accessible, interoperable, and reusable (FAIR) data principles, our method directly supports Europe’s safe and sustainable by design (SSbD) initiative. We propose embedding tri-beam datasets into regulatory standards, predictive models, and AI-driven screening workflows. Ultimately, tri-beam operando characterization represents a transformative platform for designing resilient, high-performance nanomaterials that meet the environmental and societal demands of the 21st century.
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Sep 2025
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I18-Microfocus Spectroscopy
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Thomas
Barthelay
,
Robert
Gray
,
Howard
Richards
,
Paloma
Rodriguez Santana
,
Sylvia
Britto
,
Kalotina
Geraki
,
Zhenyuan
Xia
,
Johanna
Xu
,
Leif E.
Asp
,
Chris
Bowen
,
Frank
Marken
,
Alexander
Lunt
,
Andrew
Rhead
Diamond Proposal Number(s):
[30127]
Open Access
Abstract: Structural batteries utilise the bifunctionality of carbon fibres to act as a load-bearing structure, but also as a conductive current collector for a battery electrode. Lithium-ion transport during the cycling of structural battery cathodes coated with different morphologies is investigated using Iron X-Ray Absorption Near Edge Spectroscopy (Fe XANES) and correlated to electrochemical performance. Two contrasting morphologies were produced using slurry coating and electrophoretic deposition (EPD) of lithium-iron phosphate (LFP) onto continuous carbon fibres. The ability to study the different structural battery cathode morphologies operando allows for a comparative analysis of their impact on cycling performance. The EPD-coated fibres exhibited a more homogeneous, thinner coating around the fibre compared to the thick, one-sided coating produced using slurry coating. Despite a lower initial capacity and 30 % lithium re-intercalation loss in the first cycle, EPD-coated fibres exhibited more stable capacity retention over time compared to slurry-coated counterparts. Electrochemical Impedance Spectroscopy (EIS) revealed initially high ionic resistance for the EPD-coated fibres, but a larger increase in resistance in the slurry coated electrodes over multiple cycles. This study demonstrated an innovative and novel method of analysing in greater detail, the cycling ability of the coated cathode material on carbon fibres using synchrotron radiation.
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Feb 2025
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I18-Microfocus Spectroscopy
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Yuan
Wang
,
Hamidreza
Arandiyan
,
Sajjad S.
Mofarah
,
Xiangjian
Shen
,
Stuart A.
Bartlett
,
Pramod
Koshy
,
Charles C.
Sorrell
,
Hongyu
Sun
,
Cristina
Pozo-Gonzalo
,
Kamran
Dastafkan
,
Sylvia
Britto
,
Suresh K.
Bhargava
,
Chuan
Zhao
Abstract: Producing green hydrogen in a cost-competitive manner via water electrolysis will make the long-held dream of hydrogen economy a reality. Although platinum-based catalysts show good performance towards hydrogen evolution reaction (HER), the high cost and scarce abundance challenge their economic viability and sustainability. Here, we show a non-platinum, high-performance electrocatalyst for HER achieved by engineering high fractions of stacking fault defects for MoNi4/MoO2 nanosheets (d-MoNi) through a combined chemical and thermal reduction strategy. The d-MoNi catalyst offers ultralow overpotentials of 78 and 121 mV for HER at current densities of 500 and 1000 mA cm−2 in 1 M KOH, respectively. The defect-rich d-MoNi exhibits 4 times higher turnover frequency than the benchmark 20% Pt/C, together with its excellent durability (>100 h), making it one of the best-performing non-platinum catalysts for HER. The experimental and theoretical results reveal that the abundant stacking faults in d-MoNi induce a compressive strain, decreasing the proton adsorption energy and promoting the associated combination of *H into hydrogen and molecular hydrogen desorption, enhancing the HER performance. This work provides a new synthetic route to engineer defective metal and metal alloy electrocatalysts for emerging electrochemical energy conversion and storage applications.
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Jun 2024
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[21484]
Open Access
Abstract: Using operando X-ray absorption spectroscopy in a continuous-flow microfluidic cell, we have investigated the nucleation of platinum nanoparticles from aqueous hexachloroplatinate solution in the presence of the reducing agent ethylene glycol. By adjusting flow rates in the microfluidic channel, we resolved the temporal evolution of the reaction system in the first few seconds, generating the time profiles for speciation, ligand exchange, and reduction of Pt. Detailed analysis of the X-ray absorption near-edge structure and extended X-ray absorption fine structure spectra with multivariate data analysis shows that at least two reaction intermediates are involved in the transformation of the precursor H2PtCl6 to metallic platinum nanoparticles, including the formation of clusters with Pt–Pt bonding before complete reduction to Pt nanoparticles.
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May 2023
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I18-Microfocus Spectroscopy
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Abstract: Platinum nanoparticles exhibit unique catalytic properties and have a number of important applications: as an industrial catalyst for fuel cells, in the synthesis of nitric acid, as well as in the reduction of exhaust gases from vehicles. While there have been many studies demonstrating size and morphology control of platinum nanoparticles, a molecular level understanding of the nucleation and growth mechanisms underlying nanoparticle formation, which is crucial for efficient optimization of size controlled synthesis, is lacking in the literature. Structurally incisive experimental in situ probes with enough spatial and temporal resolution are needed to monitor nucleation and growth processes.
Here we use operando X-ray Absorption Spectroscopy (XAS) coupled with continuous flow microfluidics to study the mechanisms of platinum nanoparticle formation by reduction of H2PtCl6 using ethylene glycol as a reducing agent. In contrast to a batch synthesis, a continuous flow device allows for rapid and efficient mixing of precursors and fine control over the synthesis parameters such as concentration, flow rate and temperature. The XAS results capture the intermediate stages of nanoparticle formation through to complete reduction to Pt nanoparticles. The setup described here can, in principle, be used to study nanoparticle nucleation and growth mechanisms of a wide range of nanoparticles that occur at fast (microsecond) timescales.
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Jul 2021
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B18-Core EXAFS
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Jamie W.
Gittins
,
Chloe J.
Balhatchet
,
Yuan
Chen
,
Cheng
Liu
,
David G.
Madden
,
Sylvia
Britto
,
Matthias J.
Golomb
,
Aron
Walsh
,
David
Fairen-Jimenez
,
Sian E.
Dutton
,
Alexander C.
Forse
Diamond Proposal Number(s):
[14239]
Open Access
Abstract: Two-dimensional electrically conductive metal–organic frameworks (MOFs) have emerged as promising model electrodes for use in electric double-layer capacitors (EDLCs). However, a number of fundamental questions about the behaviour of this class of materials in EDLCs remain unanswered, including the effect of the identity of the metal node and organic linker molecule on capacitive performance, and the limitations of current conductive MOFs in these devices relative to traditional activated carbon electrode materials. Herein, we address both these questions via a detailed study of the capacitive performance of the framework Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) with an acetonitrile-based electrolyte, finding a specific capacitance of 110–114 F g−1 at current densities of 0.04–0.05 A g−1 and a modest rate capability. By directly comparing its performance with the previously reported analogue, Ni3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene), we illustrate that capacitive performance is largely independent of the identity of the metal node and organic linker molecule in these nearly isostructural MOFs. Importantly, this result suggests that EDLC performance in general is uniquely defined by the 3D structure of the electrodes and the electrolyte, a significant finding not demonstrated using traditional electrode materials. Finally, we probe the limitations of Cu3(HHTP)2 in EDLCs, finding a limited stable double-layer voltage window of 1 V and only a modest capacitance retention of 81% over 30 000 cycles, both significantly lower than state-of-the-art porous carbons. These important insights will aid the design of future conductive MOFs with greater EDLC performances.
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Jun 2021
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B18-Core EXAFS
I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[22856, 22930, 24676]
Open Access
Abstract: For magnesium ion batteries (MIBs) to be used commercially, new cathodes must be developed that show stable reversible Mg intercalation. VS4 is one such promising material, with vanadium and disulfide anions [S2]2– forming one-dimensional linear chains, with a large interchain spacing (5.83 Å) enabling reversible Mg insertion. However, little is known about the details of the redox processes and structural transformations that occur upon Mg intercalation and deintercalation. Here, employing a suite of local structure characterization methods including X-ray photoelectron spectroscopy (XPS), V and S X-ray absorption near-edge spectroscopy (XANES), and 51V Hahn echo and magic-angle turning with phase-adjusted sideband separation (MATPASS) NMR, we show that the reaction proceeds via internal electron transfer from V4+ to [S2]2–, resulting in the simultaneous and coupled oxidation of V4+ to V5+ and reduction of [S2]2– to S2–. We report the formation of a previously unknown intermediate in the Mg–V–S compositional space, Mg3V2S8, comprising [VS4]3– tetrahedral units, identified by using density functional theory coupled with an evolutionary structure-predicting algorithm. The structure is verified experimentally via X-ray pair distribution function analysis. The voltage associated with the competing conversion reaction to form MgS plus V metal directly is similar to that of intermediate formation, resulting in two competing reaction pathways. Partial reversibility is seen to re-form the V5+ and S2– containing intermediate on charging instead of VS4. This work showcases the possibility of developing a family of transition metal polychalcogenides functioning via coupled cationic–anionic redox processes as a potential way of achieving higher capacities for MIBs.
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Oct 2020
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I11-High Resolution Powder Diffraction
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Simon J.
Cassidy
,
Michael J.
Pitcher
,
Jared J. K.
Lim
,
Joke
Hadermann
,
Jeremy P.
Allen
,
Graeme W.
Watson
,
Sylvia
Britto
,
Elena J.
Chong
,
David G.
Free
,
Clare P.
Grey
,
Simon J.
Clarke
Diamond Proposal Number(s):
[13284, 18786]
Open Access
Abstract: The chemical accessibility of the CeIV oxidation state enables redox chemistry to be performed on the naturally coinage-metal-deficient phases CeM1–xSO (M = Cu, Ag). A metastable black compound with the PbFCl structure type (space group P4/nmm: a = 3.8396(1) Å, c = 6.607(4) Å, V = 97.40(6) Å3) and a composition approaching CeSO is obtained by deintercalation of Ag from CeAg0.8SO. High-resolution transmission electron microscopy reveals the presence of large defect-free regions in CeSO, but stacking faults are also evident which can be incorporated into a quantitative model to account for the severe peak anisotropy evident in all the high-resolution X-ray and neutron diffractograms of bulk CeSO samples; these suggest that a few percent of residual Ag remains. A straw-colored compound with the filled PbFCl (i.e., ZrSiCuAs- or HfCuSi2-type) structure (space group P4/nmm: a = 3.98171(1) Å, c = 8.70913(5) Å, V = 138.075(1) Å3) and a composition close to LiCeSO, but with small amounts of residual Ag, is obtained by direct reductive lithiation of CeAg0.8SO or by insertion of Li into CeSO using chemical or electrochemical means. Computation of the band structure of pure, stoichiometric CeSO predicts it to be a Ce4+ compound with the 4f-states lying approximately 1 eV above the sulfide-dominated valence band maximum. Accordingly, the effective magnetic moment per Ce ion measured in the CeSO samples is much reduced from the value found for the Ce3+-containing LiCeSO, and the residual paramagnetism corresponds to the Ce3+ ions remaining due to the presence of residual Ag, which presumably reflects the difficulty of stabilizing Ce4+ in the presence of sulfide (S2–). Comparison of the behavior of CeCu0.8SO with that of CeAg0.8SO reveals much slower reaction kinetics associated with the Cu1–xS layers, and this enables intermediate CeCu1–xLixSO phases to be isolated.
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Feb 2019
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B18-Core EXAFS
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Abstract: The properties of mixed ionic–electronic conductors (MIECs) are most conveniently controlled through site-specific aliovalent substitution, yet few techniques can report directly on the local structure and defect chemistry underpinning changes in ionic and electronic conductivity. In this work, we perform high-resolution 17O (I = 5/2) solid-state NMR spectroscopy of La2-xSrxNiO4+δ, a MIEC and prospective solid oxide fuel cell (SOFC) cathode material, showing the sensitivity of 17O hyperfine (Fermi contact) shifts and quadrupolar coupling constants due to local structural changes arising from Sr substitution (x). Previously, we resolved resonances from three distinct oxygen sites (interstitial, axial, and equatorial) in the unsubstituted x = 0 material (Halat et al., J. Am. Chem. Soc. 2016, 138, 11958). Here, substitution-induced changes in these three spectral features indirectly report on the ionic conductivity, local octahedral tilting, and electronic conductivity, respectively, of the (substituted) materials. In particular, the intensity of the 17O resonance arising from mobile interstitial defects decreases, and then disappears, at x = 0.5, consistent with reports of lower bulk ionic conductivity in Sr-substituted phases. Secondly, local distortions among the split axial oxygen sites diminish, even on modest incorporation of Sr (x < 0.1), which is also accompanied by faster spin-lattice (T1) relaxation of the interstitial 17O resonances, indicating increased mobility of the associated sites. Finally, the hyperfine shift of the equatorial oxygen resonance decreases due to conversion of Ni2+ (d8) to Ni3+ (d7) by charge compensation, a mechanism associated with improved electronic conductivity in the Sr-substituted phases. Valence and coordination changes of the Ni cations are further supported by Ni K-edge X-ray absorption near edge structure (XANES) measurements, which show a decrease in the Jahn-Teller distortion of the Ni3+ sites and a Ni coordination change consistent with the formation of oxygen vacancies. Ultimately, these insights into local atomic and electronic structure that rely on 17O solid-state NMR spectroscopy should prove relevant for a broad range of aliovalently-substituted functional paramagnetic oxides.
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Jun 2018
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