I22-Small angle scattering & Diffraction
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María Calles
García
,
Hugo
Salazar
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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
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Aysun Ipek
Paksoy
,
Luis Francisco
Bobadilla
,
Rubén
Blay-Roger
,
Loukia-Pantzechroula
Merkouri
,
Victor
López-Flores
,
Claude
Coppex
,
Jelena
Jelic
,
Felix
Studt
,
Tomas
Ramirez Reina
,
José Antonio
Odriozola
,
Melis Seher
Duyar
Diamond Proposal Number(s):
[29271]
Abstract: This study reports a dual function material (DFM) composed entirely of non-precious metals for methanol production (13.8 μmol/g material) at ambient pressure from passively captured CO2 from the air. While state of the art carbon capture and utilisation (CCU) processes rely on expensive CO2 capture systems and a high-pressure catalytic reactor for methanol synthesis, this Ni-Ga-Ca DFM can be an enabler for significant energy efficiency gains in methanol synthesis from CO2 through the direct utilisation of dilute emissions and substantially lower operating pressures. Using operando DRIFT spectroscopy coupled with density functional theory, XAFS, XRD, and TEM-HAADF, a combination of Ni-Ga intermetallic species and their oxides are identified as the active sites. During cyclic operation a shift in selectivity towards methane is observed, which is associated with dynamic restructuring of the DFM. Guided by mechanistic and structural understanding, a synthesis strategy is developed to enhance cyclic stability by mitigating dealloying and Ni particle agglomeration. It is indicated that cyclic stability can be achieved by strengthening the Ni-Ga-Ca interaction, however, there remains a gradual shift in selectivity towards methane which highlights the need for further material optimisation.
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Sep 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Diamond Proposal Number(s):
[40403]
Open Access
Abstract: This study explores the effect of CeO2 doping on the catalytic performance of Fe, Co, and Ni catalysts supported on carbon nanofibers (CNFs) for hydrogen production via ammonia decomposition. Incorporating CeO2 significantly enhanced catalytic activity, achieving 90 % ammonia conversion at 600 °C. Stability tests confirmed sustained performance, maintaining high activity for at least 30 h on stream. A deep surface characterization revealed that the incorporation of Ni after the CeO2 doping created nanocatalytic portions of highly dispersed Ni/CeO2 on the CNFs structure. This guaranteed an intimate contact between the Ni and the CeO2, resulting in an increase in the H2 production rate. Notably, Ni catalysts directly supported on bulk CeO2 exhibited inferior performance, likely due to low relative surface of available ceria. These findings highlight CeO2-doped CNFs as a promising platform for scalable, high-performance hydrogen production from ammonia.
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Sep 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[34632]
Open Access
Abstract: An acetylene impurity of 0.5-3 % is present in ethylene produced from steam cracking, disrupting the polymerisation process by causing harm to the Ziegler-Natta catalyst. Achieving polymer-grade ethylene requires the removal of acetylene through chemoselective hydrogenation to ethylene, preventing over‑hydrogenation to ethane. The current state-of-the-art process employs expensive, scarce Pd nanoparticles with low selectivity. Single-atom catalysts (SACs) enhance selectivity by preferentially desorbing ethylene. Single atoms of earth-abundant iron can improve selectivity and reduce costs. Here, we introduce zeolite Y-supported single-atom iron (Fe1@Y) catalyst, prepared through in-situ hydrothermal method, which efficiently catalyses semi‑hydrogenation of acetylene to ethylene. Characterisation techniques confirm absence of Fe nanoparticles and presence of single-atom Fe sites. Fe1@Y achieves a remarkable ethylene selectivity of 93 % ± 2 % at full acetylene conversion, following a dissociative mechanism and stable operation for over 600 h. Under industrial conditions with excess ethylene in the feed, ethylene selectivity of 91 % ± 2 % was maintained at full acetylene conversion. The
of 711
achieved by Fe1@Y is ~14 times greater than previously reported zeolite-supported SACs. Changing iron dispersion from nanoparticles to single atoms significantly enhanced catalytic activity and selectivity, a strategy extendable to other moderately active metals and hydrogenation reactions.
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Sep 2025
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Abstract: Manganese (Mn) is an effective promoter of Fe-based catalysts to increase the production of carbon nanotubes (CNTs) from waste plastics but suffers from the lack of insights into how Mn affects the catalytic performance of CNTs production. Herein, we systematically investigate the promotion mechanism of Mn in Fe-based catalysts by varying the adding order of Mn and Fe during one or two-step impregnation methods. The results show that α-(Fe1-xMnx)2O3 is formed and uniformly distributed in Fe crystals when Mn and Fe are simultaneously added by the one-step impregnation method ((Mn + Fe)/MgO), resulting in the highest gas (66.3 mmol/gplastic), and CNTs (235 mg/gplastic) yields. While α-(Fe1-xMnx)2O3 in FeMn/MgO (Fe is added first and followed by Mn by two-step impregnation method) exhibited a poor distribution resulting in reduced gas and CNTs yields compared to (Mn + Fe)/MgO. For MnFe/MgO prepared by the two-step impregnation method and Mn is added first, the formed α-(Fe1-xMnx)2O3 is entirely not inserted into Fe crystals, and the corresponding catalyst exhibits lower gas and CNTs yields. The best catalytic performance of (Mn + Fe)/MgO is owing to the well-dispersed α-(Fe1-xMnx)2O3, which increases the carbon solubility capacity of the Fe crystals and regulates the equilibrium of carbon dissolution and precipitation, promoting the thermal cracking and carbon formation reactions, thereby improving the catalytic performance of CNTs and gas production.
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May 2024
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[25932, 30031]
Open Access
Abstract: The application of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) addresses challenges in water management, fuel purity, and overheating under high current density. However, phosphoric acid (PA) migration hinders their development. This study uses synchrotron-based X-ray fluorescence spectroscopy to investigate PA and catalyst migration. Interventions with single-layer graphene and electrochemically exfoliated graphene oxide improve performance and durability. X-ray absorption spectroscopy provides insights into relevant mechanisms, advancing understanding of membrane electrode assembly preparation and the intricate influences of PA and catalyst migration on performance and durability in HT-PEMFCs.
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Mar 2024
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B22-Multimode InfraRed imaging And Microspectroscopy
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Diamond Proposal Number(s):
[25407]
Open Access
Abstract: Organic photoswitchable molecules have struggled in solid-state form to fulfill their remarkable potential, in terms of photoswitching performance and long-term stability when compared to their inorganic counterparts. We report the concept of non-electron deficient host’s surface with optimal porosity and hydrophobicity, as a priori strategy to design photoefficient organic solid-state photochromic materials with outstanding mechanical robustness. It is realized by the nanoconfinement of photochromes in a host matrix possessing optimal porosity and hydrophobicity. The resulting photochromic nanocomposites can be prepared in multigram scale employing a one-pot reaction under ambient conditions. When exposed to a light stimulus including natural sunlight, the photoswitchable nanocomposite powder changes color promptly and reversibly, in a matter of seconds (5 s and 30 s under UV irradiation and sunlight, respectively) along with excellent photo-fatigue resistance, which are on a par with inorganic photochromes. Exemplars of commercially viable prototypes that are optically clear, comprising smart windows, complex photochromic sculptures, and self-erasing rewritable devices, were engineered by direct blending with resilient polymers. Notably, the use of high-stiffness polymers (Young’s modulus > 2 GPa) is no longer considered an insurmountable challenge. Finally, photochromic films with anticounterfeiting features could be manufactured through precision printing of nanocrystals by drop-on-demand inkjet printing technology.
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Oct 2023
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I11-High Resolution Powder Diffraction
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Open Access
Abstract: Efficient nitrogen oxides (NOx) removal from the urban atmosphere is still a target for the researchers. Herein, a Zn2Al-CO3 based layered double hydroxide (LDH) was doped with increasing amounts of Eu3+ (0.01–0.04) and the photocatalytic oxidation of NOx gases was investigated. The LDHs were synthesized by a facile coprecipitation method at room temperature and ambient pressure. The successful Eu3+ substitution in the LDH layers induces a shift in the M−O bonds that modifies the electronic band structure of the doped photocatalysts. Compared to the undoped LDH, the NOx removal efficiency was enhanced by ∼ 17–25 % under UV–Vis light irradiation. Remarkably, a NOx removal efficiency of ∼ 47 % was attained by the optimally doped LDH under Visible irradiation (420 nm), surpassing raw LDH (∼ 9 %). Moreover, the Eu3+ doped LDHs retained its photocatalytic efficiency during long periods of irradiation during consecutive tests with high selectivity (>90 %). Photoluminescence studies indicated that Eu3+ was located in a non-centrosymmetric position, thereby producing structural disorder within the lattice. Eu doping promoted charge separation and a higher production of ⋅OH radicals as verified by time-resolved photoluminescence and electron paramagnetic resonance, respectively. We believe this work reports unprecedent results obtained by Eu-doping of Zn2Al-based LDHs under visible light for NOx photooxidation and serves as a new strategy to prepare functional LDHs for other photocatalytic applications.
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Sep 2023
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E02-JEM ARM 300CF
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Chao
Sun
,
Matthew
Barton
,
Christopher M.
Pask
,
Mohamed
Edokali
,
Lina
Yang
,
Andrew J.
Britton
,
Stuart
Micklethwaite
,
Francesco
Iacoviello
,
Ali
Hassanpour
,
Maximilian
Besenhard
,
Rik
Drummond-Brydson
,
Ke-Jun
Wu
,
Sean M.
Collins
Diamond Proposal Number(s):
[26822, 30160]
Open Access
Abstract: Metal–organic frameworks (MOFs) have emerged as promising candidate materials for proton exchange membranes (PEMs), due to the control of proton transport enabled by functional groups and the structural order within the MOFs. In this work, we report a millifluidic approach for the synthesis of a MOF incorporating both sulfonate and amine groups, termed Cu-SAT, which exhibits a high proton conductivity. The fouling-free multiphase flow reactor synthesis was operated for more than 5 h with no reduction in yield or change in the particle size distribution, demonstrating a sustained space–time yield up to 131.7 kg m−3 day−1 with consistent particle quality. Reaction yield and particle size were controllably tuned by the adjustment of reaction parameters, such as residence/reaction time, temperature, and reagent concentration. The reaction yields from the flow reactor were 10–20% higher than those of corresponding batch syntheses, indicating improved mass and heat transfer in flow. A systematic exploration of synthetic parameters using a factorial design of experiments approach revealed the key correlations between the process parameters and yields and particle size distributions. The proton conductivity of the synthesized Cu-SAT MOF was evaluated in a mixed matrix membrane model PEM with polyvinylpyrrolidone and polyvinylidene fluoride polymers, exhibiting a promising composite conductivity of 1.34 ± 0.05 mS cm−1 at 353 K and 95% relative humidity (RH).
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Sep 2023
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Clement
Jacquot
,
Antonios
Vamvakeros
,
Andraž
Pavlišič
,
Stephen W. T.
Price
,
Hongyang
Dong
,
Dorota
Matras
,
Lidia
Protasova
,
Blaž
Likozar
,
Simon D. M.
Jacques
,
Andrew M.
Beale
,
Vesna
Middelkoop
Open Access
Abstract: This study demonstrates the characteristics of two model packing configurations: 3D printed catalyst monoliths on the one hand, and their conventional counterparts, packed beds of spheres, on the other. Cobalt deposited on alumina is selected as a convenient model system for this work, due to its wide spread use in many catalytic reactions. 3D printed constructs were produced from alumina powder impregnated with cobalt nitrate while the alumina spheres were directly impregnated with the same cobalt nitrate precursor. The form of the catalyst, the impregnation process, as well as the thermal history, were found to have a significant effect on the resulting cobalt phases. Probing the catalyst bodies in situ by XRD-CT indicated that the level of dispersion of identified Co phases (Co3O4 reduced to CoO) across the support is maintained under reduction conditions. The packed bed of spheres exhibits a non-uniform distribution of cobalt phases, including a core-shell morphology with an average crystallite size of 10-14 nm across the sphere, while the 3DP monolith exhibits a uniform distribution of cobalt phases with an average crystallite size of 5-12 nm upon reduction from Co3O4 to CoO. CFD modelling was carried out to develop digital twins and assess the effect of the geometry of both configurations on the pressure drop and velocity profiles. Finally, the activity of both Cobalt-based catalyst geometries was assessed in terms of their conversion, selectivity and turn over frequencies under model multiphase (selective oxidation) reaction conditions, which showed that the desired 3D printed monolithic geometries can offer distinct advantages to the reactor design.
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Jul 2023
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