B18-Core EXAFS
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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.
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Dec 2025
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B18-Core EXAFS
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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.
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Dec 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[36104]
Abstract: Seawater splitting has been considered an environmentally friendly and cost-effective method for hydrogen production. However, developing efficient electrocatalysts capable of enduring the severe corrosive conditions of natural seawaters for extended durations remains a notable technical challenge. Herein, the Ni3S2 supported NiFe oxalate ((NiFe)C2O4/Ni3S2) nanorod arrays were synthesised through hydrothermal and impregnation precipitation methods. Structural and spectroscopic analyses revealed that the (NiFe)C2O4/Ni3S2 catalyst formed an integrated oxide-sulfide interface with coexisting Ni–O/Ni–S coordination. This dual coordination environment, coupled with the presence of Fe in a higher oxidation state, confirmed interfacial electronic reorganization characterized by directional electron transfer from Ni to Fe. The resulting charge transfer pathway enhanced the electron delocalisation between active centers, thereby improving active site utilization. The obtained (NiFe)C2O4/Ni3S2 demonstrated remarkable catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in a simulated alkaline seawater solution (NaCl + KOH), with overpotentials of 363 mV (HER) and 295 mV (OER) at a current density of 500 mA cm−2 for industrial electrolysis requirements and remarkable stability over 100 h of durability testing. Additionally, the (NiFe)C2O4/Ni3S2 electrode pairs only required a cell voltage of 1.81 V to achieve 100 mA cm−2 with Faradaic efficiency of 98 % in 1.0 M KOH + seawater. This study presents a novel approach for fabricating multifunctional electrocatalysts, providing a promising pathway for advancing seawater electrolysis and supporting the development of cost-effective green hydrogen production technologies.
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Nov 2025
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B22-Multimode InfraRed imaging And Microspectroscopy
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Marta
Morana
,
Lorenzo
Barni
,
Haixing
Fang
,
Giulia
Marras
,
Gianfelice
Cinque
,
Antonio
Angellotti
,
Fabrizio
Nestola
,
Alla
Logvinova
,
Denis
Mikhailenko
,
Luca
Bindi
,
Vincenzo
Stagno
Diamond Proposal Number(s):
[35052]
Open Access
Abstract: The investigation of mineral inclusions in diamonds represents a unique tool to better understand the mineralogy and composition of hidden portions of Earth's mantle and, hence, determine conditions of pressure and temperature at the time of diamond formation. Using a combination of experimental techniques and different geothermobarometric approaches, we characterized a natural diamond from Udachnaya kimberlite pipe entrapping nine inclusions; the inclusions are five garnets, three clinopyroxene and one sulfide and represent an eclogitic paragenesis. Here, we adopted, for the first time, the elastic geobarometry method to the garnet-diamond inclusion-host system to calculate the entrapment conditions for the diamond-garnet pair, resulting in 5.7(±0.3) GPa at 1154 °C. These P-T data are compared with estimates obtained through chemical geothermobarometry, employing T projection onto the local geotherm, a common approach used for eclogite xenoliths in absence of robust calibrated barometers. Our data demonstrate that elastic geobarometry for the garnet-diamond pair results to be a very reliable tool to determine the diamond formation also for eclogitic systems and this will allow to expand our knowledge on eclogitic diamonds in terms of depth of formation.
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Nov 2025
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B18-Core EXAFS
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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.
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Nov 2025
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E01-JEM ARM 200CF
E02-JEM ARM 300CF
I18-Microfocus Spectroscopy
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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.
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Nov 2025
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B22-Multimode InfraRed imaging And Microspectroscopy
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A.
Angellotti
,
M.
Morana
,
L.
Barni
,
G.
Cinque
,
Y.
Lu
,
R.
Tao
,
G.
Marras
,
A.
Logvinova
,
L.
Bindi
,
D.
Mikhailenko
,
V.
Stagno
Diamond Proposal Number(s):
[35052]
Open Access
Abstract: Natural diamonds are exceptional carriers of mineralogical and chemical information from inaccessible depths of our planet. During their crystallization, they can host light elements such as H and N preserving a natural archive of mantle chemistry that, in turn, allows a better understanding of the chemical composition of the growth media, mechanisms of their formation and residence temperatures in the interior of Earth. However, how N and H distribute near entrapped minerals is still unknown. In this study we investigated the effect of chromite mineral inclusions on the spatial distribution of nitrogen and hydrogen in two natural diamonds of peridotitic origin using in situ synchrotron-based Fourier transform infrared microspectroscopy. From the acquisition and optimization of high-resolution maps, we determined the distribution of nitrogen, hydrogen, and nitrogen aggregation state.
Our results reveal a dependence between the absorption of H-related peaks with the incorporation of pairs of nitrogen atoms (NA-centers). We explain it as indication that chemical interactions between chromite and H might be masked by variations in the N aggregation state. We also conclude that synchrotron micro-FTIR is an advanced technique to assist the synthesis of N- (and H-) doped diamonds for industrial applications.
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Nov 2025
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B18-Core EXAFS
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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.
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Nov 2025
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B23-Circular Dichroism
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Leo
Delage-Laurin
,
David
Reger
,
Abdusalom A.
Suleymanov
,
Zachary
Nelson
,
Louis
Minion
,
Steven
Kooi
,
Jochen R.
Brandt
,
Giuliano
Siligardi
,
Robert P.
Cameron
,
Jessica
Wade
,
Timothy M.
Swager
,
Matthew J.
Fuchter
Diamond Proposal Number(s):
[29153, 31975, 33533]
Open Access
Abstract: Connections between magnetic field induced optical activity and chirality have a rich and complicated history. Although the broken inversion symmetry of chiral molecules generates ‘natural’ optical activity, magnetic optical activity is generated by breaking time reversal symmetry. Therefore, molecular chirality is not expected to influence magnetic optical phenomena, such as Faraday rotation. Here we show that the chiral supramolecular assembly of polymers can result in large Faraday effects (Verdet constants = 105 °T–1m–1). This strong Faraday rotation, which is amongst the highest value known for organic materials, originates from the so-called Faraday B term. Typically, B term Faraday responses are weak. We demonstrate large amplification through excitonic coupling within the supramolecular assembly, where the chirality of the system controls the assembly formed. These observations provide an alternative means to enhance the Faraday rotation of low symmetry systems and clarify the role of chirality in previous reported materials.
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Nov 2025
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I09-Surface and Interface Structural Analysis
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Diamond Proposal Number(s):
[29113]
Open Access
Abstract: LiNi0.5Mn1.5O4 (LNMO) cathodes offer a cobalt-free, high-voltage alternative to current state-of-the-art Li-ion battery cathodes, and are particularly well-suited for high-power applications due to their 3D lithium-ion pathways and structural stability. However, degradation of commercial electrolytes at high voltages exacerbates capacity decay, as instability at the cathode surface causes active material loss, surface reconstructions, thickening surface layers, and increases in internal cell resistance. Cationic substitution has been proposed to enhance surface stability, thus limiting capacity decay. Here, we demonstrate the stabilizing effect of Mg on the LNMO cathode surface, which is most evident during the early stages of cycling. This study indicates that improved O 2p-TM 3d hybridization in Mg-substituted LNMO, facilitated by Li-site defects, leads to the formation of a stable surface layer that is corrosion-resistant at high voltage. Examination of Fe-substituted and unsubstituted LNMO further confirms that the surface stability is uniquely enabled by Mg substitution. This work offers valuable insights into surface design for reducing degradation in high-voltage spinel cathodes.
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Nov 2025
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