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Abstract: Metal–organic frameworks hold immense application potential, but their stability and environmental safety remain barriers to industrial translation. Embracing the ‘safe and sustainable by design’ framework would, however, set a transformative pathway to the development of robust, recyclable metal–organic frameworks, ensuring functionality, minimal ecological impact and alignment with circular economy and chemical sustainability goals.
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Jan 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Prathmesh
Bhadane
,
Dhruv
Menon
,
Prateek
Goyal
,
Mohammad Reza
Alizadeh Kiapi
,
Biraj
Kanta Satpathy
,
Arianna
Lanza
,
Iuliia
Mikulska
,
Rebecca
Scatena
,
Stefan
Michalik
,
Priya
Mahato
,
Mehrdad
Asgari
,
Xu
Chen
,
Swaroop
Chakraborty
,
Abhijit
Mishra
,
Iseult
Lynch
,
David
Fairen-Jimenez
,
Superb K.
Misra
Diamond Proposal Number(s):
[39677, 38403]
Abstract: Recycling and recovery of rare earth elements (REEs) from electronic wastes can accelerate efforts to mitigate the environmental burden associated with their excessive mining, while catering for their growing demand. Contemporary recovery strategies are yet to make an impact at an industrial scale due to low REE uptakes, complex mechanisms, and high regeneration energies, leading to an overall poor scalability. Here, we report a two-dimensional metal–organic framework (BNMG-1) featuring a dense arrangement of active adsorption sites for the high uptake of heavy and light REEs. BNMG-1 with a lateral dimension of ca. 350 nm and a thickness of 14 nm was synthesized via a facile one-pot reaction using a green solvent under room temperature and atmospheric pressure. The two-dimensional structure of BNMG-1 was resolved using three-dimensional electron diffraction and EXAFS analysis. Batch experiments showed BNMG-1 to have an adsorption capacity of 355.8 mg/g for Nd3+, 323.1 mg/g for Y3+, 331 mg/g for Dy3+, 329mg/g for Tb3+ and 333 mg/g for Eu3+, which is a near-benchmark performance for a non-functionalised MOF. The adsorption efficiency for Nd3+ reached 99 % by 6 h and 88 % by 48 h for Y3+. The adsorption efficiency did not get affected over a pH range of 3 to 6 and retained > 99 % of its adsorption capacity for up to 4 cycles. For application on real-life samples, CFL lamp waste and waste magnets were used as a reservoir of heavy (Yttrium) and light (Neodymium) REEs. BNMG-1 demonstrates an efficient recovery of 57 % for Neodymium from scrap magnets and 27 % for Yttrium from waste fluorescent lamps. This performance, which is maintained under acidic conditions and over multiple cycles, highlights the competitiveness of BNMG-1 for the economic large-scale recovery of REEs.
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Dec 2024
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[33172, 34243]
Open Access
Abstract: We investigate magnesium–iron pyroborate MgFeB2O5 as a potential cathode material for rechargeable magnesium-ion batteries. Synchrotron powder X-ray diffraction and Mössbauer spectroscopy confirm its successful synthesis and iron stabilization in the high-spin Fe(II) state. Initial electrochemical testing against a lithium metal anode yields a first charge capacity near the theoretical value (147.45 mAh·g–1), suggesting MgFeB2O5 as a promising cathode candidate. However, multimodal analyses, including scanning electron microscopy energy-dispersive X-ray (SEM-EDS) analysis, operando X-ray absorption near edge spectroscopy (XANES), and Mössbauer spectroscopy, reveal the absence of any Fe redox reactions. Instead, we propose that the source of the observed capacity involves the irreversible reaction of a small (4–7 wt%) Fe metal impurity. These findings highlight the need for diverse characterization techniques in evaluating the performance of new Mg cathode materials, since promising initial cycling may be caused by competing side reactions rather than Mg (de)intercalation.
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Dec 2024
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B18-Core EXAFS
E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[35687, 38973]
Open Access
Abstract: The induction of structural distortion in a controlled manner through tilt engineering emerges as a potent method to finely tune the physical characteristics of Prussian blue analogues. Notably, this distortion can be chemically induced by filling their pores with cations that can interact with the cyanide ligands. With this objective in mind, we optimized the synthetic protocol to produce the stimuli-responsive Prussian blue analogue AxMn[Fe(CN)6] with A = K+, Rb+, and Cs+, to tune its stimuli-responsive behavior by exchanging the cation inside pores. Our crystallographic analyses reveal that the smaller the cation, the more pronounced the structural distortion, with a notable 20-degree Fe-CN bending when filling the cavities with K+, 10 degrees with Rb+, and 2 degrees with Cs+. Moreover, this controlled distortion offers a means to switch on/off its stimuli-responsive behavior, while modifying its magnetic response. Thereby empowering the manipulation of the PBA's physical properties through cationic exchange.
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Aug 2024
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
E02-JEM ARM 300CF
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Longxiang
Liu
,
Liqun
Kang
,
Jianrui
Feng
,
David G.
Hopkinson
,
Christopher S.
Allen
,
Yeshu
Tan
,
Hao
Gu
,
Iuliia
Mikulska
,
Veronica
Celorrio
,
Diego
Gianolio
,
Tianlei
Wang
,
Liquan
Zhang
,
Kaiqi
Li
,
Jichao
Zhang
,
Jiexin
Zhu
,
Georg
Held
,
Pilar
Ferrer
,
David
Grinter
,
June
Callison
,
Martin
Wilding
,
Sining
Chen
,
Ivan
Parkin
,
Guanjie
He
Diamond Proposal Number(s):
[30614, 32058, 32035, 32117, 33466, 29271]
Open Access
Abstract: Electrochemical hydrogen peroxide (H2O2) production (EHPP) via a two-electron oxygen reduction reaction (2e- ORR) provides a promising alternative to replace the energy-intensive anthraquinone process. M-N-C electrocatalysts, which consist of atomically dispersed transition metals and nitrogen-doped carbon, have demonstrated considerable EHPP efficiency. However, their full potential, particularly regarding the correlation between structural configurations and performances in neutral media, remains underexplored. Herein, a series of ultralow metal-loading M-N-C electrocatalysts are synthesized and investigated for the EHPP process in the neutral electrolyte. CoNCB material with the asymmetric Co-C/N/O configuration exhibits the highest EHPP activity and selectivity among various as-prepared M-N-C electrocatalyst, with an outstanding mass activity (6.1 × 105 A gCo−1 at 0.5 V vs. RHE), and a high practical H2O2 production rate (4.72 mol gcatalyst−1 h−1 cm−2). Compared with the popularly recognized square-planar symmetric Co-N4 configuration, the superiority of asymmetric Co-C/N/O configurations is elucidated by X-ray absorption fine structure spectroscopy analysis and computational studies.
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May 2024
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B18-Core EXAFS
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Diamond Proposal Number(s):
[30136]
Open Access
Abstract: CuFeS2 (chalcopyrite) is a promising n-type thermoelectric candidate for low-grade waste heat recovery. In this work, chromium-containing CuFeS2 materials of general formula Cu1−xCrxFeS2 (0.0 ≤ x ≤ 0.1) were prepared via solid-state synthesis. Efforts to substitute chromium in CuFeS2 leads to the preferential formation of a composite, in which lamellar precipitates of a Cr-rich, spinel-type [Cu,Fe,Cr]3S4 phase, are embedded in the unsubstituted CuFeS2 matrix. X-ray absorption near-edge spectroscopy (XANES) reveals that the electronic structure of copper, iron and sulfur in the principal CuFeS2 phase remains unaltered by chromium incorporation. However, the formation of [Cu,Fe,Cr]3S4 precipitates alters the Cu[thin space (1/6-em)]:[thin space (1/6-em)]Fe ratio of the CuFeS2 phase, producing a change in the net carrier concentration through reduction of a portion of Fe3+ ions to Fe2+. The chromium content of the spinel precipitates determines the extent of the change in the Cu[thin space (1/6-em)]:[thin space (1/6-em)]Fe ratio of the main CuFeS2 phase, and hence, indirectly affects the electrical properties. The micro/nanometre-sized [Cu,Fe,Cr]3S4 precipitates and nanoscale dislocations enable a broad spectrum of heat-carrying acoustic phonons to be scattered, resulting in a significantly reduced lattice thermal conductivity. Combined with an enhanced power factor, a maximum thermoelectric figure-of-merit, zT of 0.31 at 673 K is achieved for the x = 0.08 sample; a three-fold increase over that of the pristine phase.
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Oct 2023
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B18-Core EXAFS
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Diamond Proposal Number(s):
[32410]
Open Access
Abstract: Ir1–xCoxO2 thin films have been prepared by reactive co–sputtering deposition at room temperature. Composition, structure, electronic properties and electric and magnetic behavior have been analyzed by different techniques including XRR, XRD, TEM microscopy, SQUID magnetometry, electrical resistivity and XAS spectroscopy. After annealing, an Ir1–xCoxO2 substitutional solid solution phase with rutile crystal structure was achieved for a wide Co-doping range 0 ≤ x ≤ 0.6. Starkly departing from the highly insulating behavior of CoO and Co3O4, the electrical resistivity at room temperature of our films is only slightly higher than that of IrO2. Likewise, our work shows that the magnetic response of the doped films is very similar to that of the paramagnetic parent IrO2. Neither ferromagnetism nor enhanced paramagnetism is observed. XAS spectra indicate a Co3+ oxidation state and, correspondingly, an oxidation state of ∼5+ for Ir ions in the polycrystalline Ir0.6Co0.4O2 film. By application of sum rules, a 13% increase in the spin–orbit coupling is found despite the lattice shrinkage causes a detrimental bandwidth broadening.
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Sep 2023
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Anokhi
Shah
,
Michael J.
Taylor
,
Giulia
Molinaro
,
Sellamuthu
Anbu
,
Margaux
Verdu
,
Lucy
Jennings
,
Iuliia
Mikulska
,
Sofia
Diaz-Moreno
,
Hassane
El Mkami
,
Graham M.
Smith
,
Melanie M.
Britton
,
Janet E.
Lovett
,
Anna F. A.
Peacock
Diamond Proposal Number(s):
[18941]
Open Access
Abstract: We report the preparation and spectroscopic characterization of a highly elusive copper site bound exclusively to oxygen donor atoms within a protein scaffold. Despite copper generally being considered unsuitable for use in MRI contrast agents, which in the clinic are largely Gd(III) based, the designed copper coiled coil displays relaxivity values equal to, or superior than, those of the Gd(III) analog at clinical field strengths. The creation of this new-to-biology proteinaceous CuOx-binding site demonstrates the power of the de novo peptide design approach to access chemistry for abiological applications, such as for the development of MRI contrast agents.
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Jul 2023
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I20-EDE-Energy Dispersive EXAFS (EDE)
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Abstract: Cu-BTC metal-organic framework (MOF) has been found to be a promising candidate for removing hazardous substances from air via adsorption1. To understand the role that the copper sites in Cu-BTC play in the adsorption process, we have performed a detailed X-ray absorption spectroscopy (XAS) study. Conventional XAS and high energy resolution fluorescence detection XAS (HERFD-XAS) were collected on degassed Cu-BTC, and after being exposed to CO2, water and benzene. The EXAFS analysis reveals that, although the local environment around the copper centers in all samples is similar, differences can be found in the first and second coordination shells. We have found that the Cu-O distance in the first coordination shell is slightly larger when the sample is immersed in water and benzene than in the degassed sample, while it does not change for the sample exposed to CO2. Small differences are also observed in the Cu-Cu distance, gradually increasing from 2.49 Å in the degassed sample, to 2.52 Å, 2.58 Å and 2.63 Å upon adsorption of CO2, benzene and water, respectively. HERFD-XAS has been used to obtain information about the electronic and geometric structure around the copper metal centers, as the use of high energy resolution enhances the features in the XANES spectrum enabling the detection of subtle changes2. We have observed differences in the intensity and the energy position of some of the XANES spectral features upon adsorption of different adsorbates that can be attributed to changes in the local environment around the copper centers, as detected in the EXAFS analysis.
In this study we show that XAS is a powerful and very sensitive tool for studying host-guest interactions in MOFs, providing atomic-level insights into adsorption mechanisms.
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Jul 2021
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I20-Scanning-X-ray spectroscopy (XAS/XES)
Detectors
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Open Access
Abstract: Diamond Light Source (DLS) I20-Scanning is a high flux X-ray Absorption Spectroscopy (XAS) beamline optimized for challenging samples, operating between 4keV and 20keV. The principal detector used for collecting XAS in fluorescence mode is a Canberra 64-pixel Monolithic Segmented Hyper Pure Germanium Detector (HPGe) historically partnered with the STFC Xspress2 Digital Pulse Processor (DPP). Prior signal analysis had shown that key parameters such as Energy Resolution and Peak-to-Background ratio are compromised by pixel-to-pixel crosstalk within the detector, especially at higher count rates (>250kcps per pixel). The DLS Detector Group have developed the new Xspress4 DPP to address such issues. This results in typically a factor 3-7 increase in detector system count rate for the same Energy Resolution and Peak-to-Background ratio compared to the previous state-of-the-art DPP. An overview of the complete detector system is given and recent results obtained during the commissioning on the beamline are shown. Further, comparative results from challenging experiments are also shown, demonstrating the improved performance attainable at the previous high count rate by partnering legacy HPGe Detectors with the latest DPP technology.
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Jan 2019
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