B18-Core EXAFS
|
Open Access
Abstract: Metal nanoparticles are widely considered for heterogeneous catalysis due to their high atomic efficiency and tunable active microenvironment, but their specific functional tendencies are still unclear. Here, we report that a Rh@ZrO2/NC catalyst with only 0.1 wt% Rh exhibits exceptional catalytic performance and high selectivity (p-nitroacetophenone conversion-98.6 %, p-aminoacetophenone selectivity-100 %, r-56.4 molp-nitroacetophenone/(molRh·min)) towards the hydrogenation of the -NO2 group in nitroarene to -NH2. This is because the interaction between Rh species and “ZrO2-N” results in significant hydrogen spillover in the catalyst, as supported by DFT calculations. Extensive characterizations from TG, DTG, NAP-XPS, in-situ Raman spectroscopy, in-situ DRIFT spectroscopy and DFT calculations further confirm the adsorption, activation and dissociation of hydrogen on Rh nanoparticles. The H* species migrate readily over ZrO2-NC, to facilitate the catalytic activity and selectivity for the hydrogenation of nitroarene. This study presents a new approach to develop highly efficient and selective metal nanoparticle-catalysts for cost-effective hydrogenation reactions.
|
Dec 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[36598]
Open Access
Abstract: O3 phase NiFeMn- based layered transition metal oxides have attracted interest for positive electrode materials for Na-ion batteries. However, they generally suffer from challenges like phase transitions and Fe migration. Recently, the substitution of Ca into the Na layer, serving as a ‘pillar’, has proven to be an effective approach to overcome these challenges. Here, we systematically studied the composition-dependent Ca pillaring effect on the electrochemical performance and structure evolution of two O3 phase NiFeMn-based layered transition metal oxides. It is found that, although moderate Ca doping in high-Ni system - Na1-2xCaxNi0.25Mn0.25Fe0.5O2 (x = 0.00, 0.03) enhances cycling stability and reduces polarization, excessive doping compromises rate capability and does not effectively prevent Fe migration. Conversely, high-Mn system - Na1-2xCaxNi0.17Mn0.33Fe0.5O2 (x = 0.00, 0.04) exhibits a more robust and beneficial response to Ca incorporation, showing enhanced structural integrity, improved redox reversibility, and effective suppression of Fe migration. This study provides insights into the tunable chemical environments of transition metal oxides, thereby advancing the design of high-performance positive electrode materials and contributing to the development of next-generation sodium-ion batteries.
|
Dec 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[32381]
Abstract: This study aimed at determining Ni and Co leaching kinetics from a New Caledonian laterite in an acidic medium (H2SO4 pH 1.5) and in a reductive environment (addition of SO32− or Fe(II)) at 46 °C. The mineralogical study revealed that Co was mainly carried by Mn oxyhydroxides in the limonite sample. Conversely, Ni was hosted by both Fe and Mn oxyhydroxides. In the presence of a reductive reagent, Mn oxyhydroxides dissolved rapidly compared to goethite, the main Fe oxyhydroxide in the sample. Co, Mn and Ni reductive leaching yields reached 79 %, 83 % and 9 % respectively after 2 days. Based on these results, a Mn oxides concentrate was produced in order to efficiently leach Co while limiting Fe oxyhydroxide dissolution. This concentrate resulted from a combination of particle size and gravity separation steps. The volume/mass of sample was drastically decreased since the mass of the final sample was only 3.3 % of the initial one. Co content increased from 0.16 wt% in the limonite to 2.3 wt% in the concentrate, representing an enrichment factor of 13.8 and recovery yield of 60 %. Co, Mn and Ni leaching yields reached 87 %, 95 % and 80 % respectively in the Mn oxides concentrate leaching experiment. The difference in Ni behaviour was consistent with the mineralogical composition: Ni was mainly carried by the goethite in the laterite, while it was hosted mainly by the Mn oxyhydroxides in the Mn oxides concentrate. This study gives a proof of concept for the development a robust pre-concentration process to recover Co.
|
Nov 2025
|
|
E01-JEM ARM 200CF
E02-JEM ARM 300CF
I18-Microfocus Spectroscopy
|
N.
Topping
,
J. C.
Bridges
,
L. J.
Hicks
,
L.
Petera
,
C. S.
Allen
,
J.
Ryu
,
D. G.
Hopkinson
,
M.
Danaie
,
L.
Blase
,
F. M.
Willcocks
,
G.
Douglas
,
H. G.
Changela
,
T.
Noguchi
,
T.
Matsumoto
,
A.
Miyake
Diamond Proposal Number(s):
[30752, 31953, 32874, 35976, 29615, 31641, 35046]
Open Access
Abstract: A correlative multi-technique approach, including electron microscopy and X-ray synchrotron work, has been used to obtain both structural and compositional information of a sulfur-bearing serpentine identified in several carbonaceous chondrites (Winchcombe CM2, Aguas Zarcas CM2, Ivuna CI, and Orgueil CI), and in Ryugu samples returned by the Hayabusa2 mission. S-K edge X-ray absorption spectroscopy was used to determine the oxidation state of sulfur in the serpentine in all samples except Ryugu. The abundance of this phase varies across these samples, with the largest amount in Winchcombe; ~12 vol% of phyllosilicates are identified as sulfur-bearing serpentine characterized by ~10 wt% SO3 equivalent. HRTEM studies reveal a d001-spacing range of 0.64–0.70 nm across all sulfur-bearing serpentine sites, averaging 0.68 nm, characteristic of serpentine. Sulfur-serpentine has variable S6+/ΣStotal values and different sulfur species dependent on specimen type, with CM sulfur-bearing serpentine having values of 0.1–0.2 and S2− as the dominant valency, and CIs having values of 0.9–1.0 with S6+ as the dominant valency. We suggest sulfur is structurally incorporated into serpentine as SH− partially replacing OH−, and trapped as SO42− ions, with an approximate mineral formula of (Mg Fe2+ Fe3+ Al)2-3(Si Al)2O5(OH)5-6(HS−)1-2(SO4)2−0.1-0.7. We conclude that much of the material identified in previous studies of carbonaceous chondrites as TCI-like or PCPs could be sulfur-bearing serpentine. The relatively high abundance of sulfur-bearing serpentine suggests that incorporation of sulfur into this phase was a significant part of the S-cycle in the early Solar System.
|
Nov 2025
|
|
B18-Core EXAFS
|
Jingwei
Wang
,
Kaiyang
Xu
,
Zhipeng
Yu
,
Hang
Cui
,
Haoliang
Huang
,
Chenyue
Zhang
,
Run
Ran
,
Liyuan
Zeng
,
Yang
Zhao
,
Xinyi
Xiang
,
Weifeng
Su
,
Yaowen
Xu
,
Sitaramanjaneya
Mouli Thalluri
,
Fei
Lin
,
Lifeng
Liu
Diamond Proposal Number(s):
[36104]
Open Access
Abstract: Widespread deployment of proton exchange membrane water electrolyzers (PEMWE) relies on acidstable oxygen evolution reaction (OER) catalysts capable of operating at high current densities.Inspired by the robust chemistry of lead-acid batteries, we introduce lead (Pb) into ruthenium-iridium mixed oxide (RuIrO x ) through a facile sol-gel method. The as-prepared RuIrPbO x nanoparticulate catalysts with the optimal composition (Ru 0.5 Ir 0.4 Pb 0.1 O x ) achieve an overpotential of 241 mV at 10 mA cm -2 and exceptional stability of 1000 hours at a high current density of 100 mA cm -2 without degradation. In-situ differential electrochemical mass spectrometry (DEMS) indicates that doping RuIrO x with an appropriate amount of Pb helps to suppress the participation of lattice oxygen during OER, contributing to structural preservation and long-term stability. Density functional theory (DFT) calculations reveal that Pb doping effectively modulates the electronic structure of Ru sites, reducing Ru-O covalency, which in turn increases Ru dissolution energy and therefore prevents Ru leachinga key degradation pathway for Ru-containing OER catalysts. When integrated into a membrane electrode assembly (MEA), the PEMWE cell can operate at a large current density of 3.0 A cm -2 under 1.96 V (@60°C) for 400 hours with minimal performance degradation, demonstrating significant potential of the Ru 0.5 Ir 0.4 Pb 0.1 O x as an efficient and durable OER catalyst for practical applications under demanding conditions.
|
Nov 2025
|
|
I18-Microfocus Spectroscopy
|
Ian T.
Burke
,
Patrizia
Onnis
,
Alex L.
Riley
,
Catherine J.
Gandy
,
Violeta
Ramos
,
Gavyn K.
Rollinson
,
Patrick
Byrne
,
Richard A.
Crane
,
Karen A.
Hudson-Edwards
,
Elin
Jennings
,
William M.
Mayes
,
J. Frederick W.
Mosselmans
,
Adam P.
Jarvis
Diamond Proposal Number(s):
[29808, 31675]
Open Access
Abstract: The erosion of legacy coastal municipal solid waste landfill sites will result in the dispersion of particulate material into nearby ecosystems with potential for effects on marine populations. Information on the speciation and solid phase associations of metal(loid) contaminants will help to predict contaminant behaviour and better understand ecosystem risks. Here, we investigate the solid phase composition of, and metal(loid) leaching from, fine fraction materials recovered from three actively eroding coastal landfill sites. High concentrations of a range of potentially toxic elements (As, Cd, Cr, Cu, Pb, Ni and Zn) were present in multiple samples, but metal(loid) leaching rates were very low (≪1 wt%) in both deionised water and seawater solutions. Therefore, particulate dispersion is the most likely mode of contaminant transport occurring at these sites. The fine fraction materials were dominated by fine sand sized (63–180 μm) quartz grains and silt sized (<63 μm) matrix components, which were likely to be poorly retained on beaches and easily transported offshore. Four priority contaminants (As, Cu, Pb and Zn) were found to occur primarily in adsorbed or precipitate forms, as either coatings on other particles or as discrete <10 μm particles. Dilution of these fine-grained contaminated particles within natural pelitic sediments will likely reduce the overall ecosystems impacts; but the risks to filter and bottom feeding organisms, and the potential for biomagnification across trophic levels are poorly understood.
|
Oct 2025
|
|
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
E02-JEM ARM 300CF
I11-High Resolution Powder Diffraction
|
Mengqi
Duan
,
Shuai
Guo
,
Wentian
Niu
,
Hangjuan
Ren
,
Thomas
Dittrich
,
Dongpei
Ye
,
Lucy
Saunders
,
Sarah
Day
,
Veronica
Celorrio
,
Diego
Gianolio
,
Peixi
Cong
,
Robert S.
Weatherup
,
Robert
Taylor
,
Songhua
Cai
,
Yiyang
Li
,
Shik Chi Edman
Tsang
Diamond Proposal Number(s):
[35749, 35750, 35961, 37117]
Open Access
Abstract: Two-dimensional layered perovskite oxides have emerged as promising photocatalysts for solar-driven hydrogen evolution. Although doping has been widely employed to enhance photocatalytic performance, its role in modulating the electronic structure and the local chemical environment of these materials remains poorly understood. Here in this study, we investigate the codoping of Rh and La into exfoliated nanosheets of the Dion–Jacobson perovskite KCa2Nb3O10 to enhance photocatalytic hydrogen evolution reaction (HER) activity. A substantial increase in H2 evolution rate, from 12.3 to 69.0 μmol h–1, was achieved at an optimal doping level of 0.2 wt % Rh and 1.3 wt % La. Comprehensive structural and spectroscopic analyses, including synchrotron techniques and high-resolution microscopy, revealed that Rh3+ substitutes Nb5+ to introduce shallow 4d acceptor states that mediate charge separation, while La3+ substitutes Ca2+, compensates for aliovalent charge imbalance, and modulates local lattice distortions and oxygen vacancy formation. This codoping strategy enhances charge carrier lifetime and separation efficiency through a trap-mediated mechanism. The observed volcano-shaped activity trend highlights a narrow compositional window, where electronic and structural factors are optimally balanced. These findings establish a mechanistic foundation for defect engineering in layered perovskites and offer a pathway for the rational design of photocatalysts.
|
Oct 2025
|
|
I14-Hard X-ray Nanoprobe
|
Gaewyn
Ellison
,
Rhiannon E.
Boseley
,
Meg
Willans
,
Sarah
Williams
,
Evelyn S.
Innes
,
Paige
Barnard
,
Julia
Koehn
,
Somayra S. A.
Mamsa
,
Paul
Quinn
,
Daryl L.
Howard
,
Simon A.
James
,
Mark J.
Hackett
Diamond Proposal Number(s):
[34101]
Open Access
Abstract: Understanding the role of metal ions in normal and abnormal cell function continues to emerge as a critical research area in the biological and biochemical sciences. This is especially true in the context of brain health and neurodegenerative diseases, as the brain is especially enriched in metal ions. A range of microscopy and bioanalytical techniques are available to assist in characterizing and observing changes to the brain metallome. As is the case in many other scientific fields, the integration of multiple analytical methods often yields a more complete chemical picture and deeper biological understanding. Herein, we present a case study applying 4 different analytical methods to provide spatially resolved characterization of chemical and biochemical parameters relating to the iron (Fe) metallome within a specific brain region, cornu ammonis sector 1 (CA1) of the hippocampus. The CA1 hippocampal sector was chosen for investigation due to its known endogenous enrichment in Fe and its selective vulnerability to neurodegeneration. The 4 analytical techniques applied were X-ray fluorescence microscopy (to quantify Fe distribution); X-ray absorption near-edge structure (XANES) spectroscopy to reveal information on Fe oxidation state and coordination environment; immuno-fluorescence to reveal relative abundance of Fe storage proteins (heavy chain ferritin and mitochondrial ferritin); and spatial transcriptomics to reveal gene expression pathways relevant to Fe homeostasis. Collectively, the results highlight that although pyramidal neurons in lateral and medial regions of the hippocampal CA1 sector are morphologically similar, key differences in the Fe metallome are evident. The observed differences within the hippocampal CA1 sector potentially indicate a higher oxidative environment and higher metabolic turnover in medial CA1 neurons relative to lateral CA1 neurons, which may account for the heightened vulnerability to neurodegeneration that is observed in the medial CA1 sector.
|
Oct 2025
|
|
B18-Core EXAFS
|
Diamond Proposal Number(s):
[38597]
Open Access
Abstract: Extra-large-pore Ge-containing GTM chiral zeolite catalysts have recently proved useful asymmetric catalysts, with chirality emerging from their chiral confined nanospace. However, so far these exceptional materials have suffered from low framework stability in the presence of water and moderate catalytic enantioselectivity in the ring-opening of chiral trans-stilbene oxide with 1-butanol used as a test reaction. Here, we report that these chiral zeolite catalysts can be easily stabilized upon exposure of the calcined material to 1-butanol, providing stability against water and, most importantly, prompting a preactivation of the chiral active sites that boosts their enantioselective properties, reaching unprecedented enantiomeric excesses up to 88% where one enantiomer reacts 16 times more than the other. A range of physicochemical studies, including in situ Fourier transform infrared (FTIR) and X-ray absorption spectroscopy, indicates that framework Ge sites increase their coordination environment upon interaction with 1-butanol molecules, which after a thermal treatment above 100 °C remain irreversibly bound to Ge as a consequence of a condensation and dehydration reaction, providing a route to easily functionalize these materials. These preactivated GTM asymmetric catalysts act similarly to enzymes by controlling the confinement of the chiral reactants in particular orientations through coordination with Ge and development of H-bonds with nearby hydroxyl groups, thus attaining enantioselective catalytic activities close to those reached by enzymatic systems but with the crucial advantage associated with heterogeneous catalysts and, notably, the possibility of preparing both enantiomeric versions of the catalyst by using an easily accessible alkaloid.
|
Oct 2025
|
|
B18-Core EXAFS
|
Rachael
Quintin-Baxendale
,
Maria
Sokolikova
,
Yemin
Tao
,
Evan
Fisher
,
Nagaraju
Goli
,
Haoyu
Bai
,
James
Murawski
,
Guangmeimei
Yang
,
Veronica
Celorrio
,
Caiwu
Liang
,
Reshma R.
Rao
,
Ifan E. L.
Stephens
,
Cecilia
Mattevi
Diamond Proposal Number(s):
[34275]
Open Access
Abstract: IrO2 is one of the most widely investigated electrocatalysts for oxygen evolution reaction in an acidic environment. Increasing the mass activity is an effective way of decreasing the loading of Ir, to ultimately reduce costs. Here, we demonstrate the crystal-phase engineering of two different potassium iridate polymorphs obtained by designing a selective solid-state synthesis of either one-dimensional K0.25IrO2 nanowires with a hollandite crystal structure or two-dimensional KIrO2 hexagonal platelets. Both structures present increased specific and mass electrocatalytic activities for the water oxidation reaction in acidic media compared to commercial rutile IrO2 of up to 40%, with the 1D nanowires outperforming the 2D platelets. XANES, extended X-ray absorption fine structure, and X-ray diffraction investigations prove the structural stability of these two different allotropes of KxIrO2 compounds upon electrocatalytic testing. These low-dimensional nanostructured 1D and 2D KxIrO2 compounds with superior mass activity to commercial IrO2 can pave the way toward the design of new electrocatalyst architectures with reduced Ir loading content for proton exchange membrane water electrolyzer (PEMWE) anodes.
|
Oct 2025
|
|
