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):
[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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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Abstract: Biocatalytic hydrogen atom transfer (HAT) holds the potential to help address some long-standing challenges in organic synthesis. Although several families of enzymes rely on cysteine to perform HAT, these enzymes are rather impractical for synthetic purposes. To circumvent possible side reactions associated with cysteinyl radicals, we report herein artificial hydrogen atom transferases (AHATases) with an abiological thiophenol cofactor, capitalizing on biotin–streptavidin technology. Chemogenetic optimization afforded an AHATase with good reactivity and high enantioselectivity (er up to 93:7) for the photoinduced radical hydroamination of alkenes. Crystal structures suggest that aromatic-sulfur interactions are key contributing factors to cofactor anchoring and enantioinduction. Mechanistic studies support H atom abstraction and donation processes, both of which are catalyzed by the AHATase. Our work highlights the synthetic potential of thiol-based biocatalytic HAT and expands the repertoire of HAT biocatalysis.
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Nov 2025
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Open Access
Abstract: Biofuels are critical drop-in replacement energy sources to support the decarbonisation of hard-to-abate sectors such as aviation and marine shipping. Transesterification of non-edible oils is a well-established route to biodiesel as a versatile liquid transport fuel, but is challenging to scale using existing homogeneous liquid base catalysts. In this work, we report the synthesis, characterisation, and application of silica-supported MgO solid base catalysts for triglyceride transesterification with methanol and highlight the impact of silica pore structure on performance. True liquid crystal templating enables the one-pot synthesis of mesoporous MgO/SBA-15 catalysts with variable Mg content, or hierarchical macroporous–mesoporous MgO/SBA-15 analogues through the addition of polystyrene nanospheres. Both MgO/SBA-15 families exhibit highly ordered pore networks; however, ~280 nm macropores stabilise Mg-O-Si interfacial species even at high Mg loading, in contrast to the mesoporous support that permits sintering of ~14 nm MgO nanocrystals. Hierarchical porous MgO/SBA-15 catalysts exhibit higher specific activity and conversion of tributyrin to methyl butyrate than their mesoporous analogues (3 mmol⋅h−1⋅g−1 versus 2 mmol⋅h−1⋅g−1 at 60 °C and 11 wt% Mg). The magnitude of this rate enhancement increases with triglyceride chain length, being approximately three-fold for trilaurin (C12) transesterification at 90 °C, attributed to superior in-pore mass transport of bulky reactants through the hierarchical porous catalyst.
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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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B18-Core EXAFS
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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.
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Oct 2025
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Emma
Van Der Minne
,
Priscila
Vensaus
,
Vadim
Ratovskii
,
Seenivasan
Hariharan
,
Jan
Behrends
,
Cesare
Franchini
,
Jonas
Fransson
,
Sarnjeet S.
Dhesi
,
Felix
Gunkel
,
Florian
Gossing
,
Georgios
Katsoukis
,
Ulrike I.
Kramm
,
Magalí
Lingenfelder
,
Qianqian
Lan
,
Yury V.
Kolen'Ko
,
Yang
Li
,
Ramsundar Rani
Mohan
,
Jeffrey
Mccord
,
Lingmei
Ni
,
Eva
Pavarini
,
Rossitza
Pentcheva
,
David H.
Waldeck
,
Michael
Verhage
,
Anke
Yu
,
Zhichuan J.
Xu
,
Piero
Torelli
,
Silvia
Mauri
,
Narcis
Avarvari
,
Anja
Bieberle-Hütter
,
Christoph
Baeumer
Open Access
Abstract: A central challenge in water electrolysis lies with the oxygen evolution reaction (OER) where the formation of molecular oxygen (O2) is hindered by the constraint of angular momentum conservation. While the reactants OH− or H2O are diamagnetic (DM), the O2 product has a paramagnetic (PM) triplet ground state, requiring a change in spin configuration when being formed. This constraint has prompted interest in spin-selective catalysts as a means to facilitate OER. In this context, the roles of magnetism and chirality-induced spin selectivity (CISS) in promoting the OER reaction have recently been investigated through both theoretical and experimental studies. However, pinpointing the key principles and their relative contribution in mediating spin-enhancement remains a significant challenge. This roadmap offers a forward-looking perspective on current experimental trends and theoretical developments in spin-enhanced OER electrocatalysis and outlines strategic directions for integrating incisive experiments and operando approaches with computational modeling to disentangle key mechanisms. By providing a conceptual framework and identifying critical knowledge gaps, this perspective aims to guide researchers toward dedicated experimental and computational studies that will deepen the understanding of spin-induced OER enhancement and accelerate the development of next-generation catalysts.
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Oct 2025
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[32728]
Open Access
Abstract: Certain members of the bacterial cytochrome P450 152 family (CYP152) are peroxygenases that catalyse the decarboxylation of fatty acids into terminal olefins making them attractive biocatalysts for biofuel production. To date, the characterisation of decarboxylating CYP152s has mainly focused on their reaction with saturated fatty acid substrates. CYP152s are often co-purified with a bound substrate, which is generally removed before further experiments are conducted. In the present work we identified that heterologous over-expressed CYP152 from Staphylococcus aureus (OleTSa) is co-purified with the trans-monounsaturated C18:1 fatty acid, elaidic acid. We report the spectral, thermodynamic and kinetic characteristics of OleTSa bound to both elaidic acid and its saturated counterpart, stearic acid. Despite differing spectral profiles, metabolic and kinetic studies reveal that OleTSa is capable of decarboxylating elaidic acid, converting it to heptadeca-1,8-diene following addition of hydrogen peroxide, at the same rate and chemoselectivity as the conversion of stearic acid to 1-heptadecane. The X-ray crystal structure of the as purified OleTSa in complex with elaidic acid is also presented, allowing for several key residues to be identified for site-directed mutagenesis studies. The influence of the site-directed variants on C18:0 and C18:1 product formation, binding thermodynamics and kinetics have been investigated, showing that while spectral differences occur as a likely result of perturbing the binding pocket, this does not alter the chemoselectivity of the enzyme. Our work provides important insights into the mechanism of decarboxylation of an unsaturated fatty acid substrate by OleTSa potentially expanding the sustainable substrate space available for CYP152s.
Graphical abstract
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Oct 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[23087]
Open Access
Abstract: The utilization of CO2 as a sustainable feedstock for oxygenated polymers offers a promising route to high-performance materials while addressing environmental challenges. This study investigates the synthesis of high-molar-mass, nonlinear polymer architectures using switchable catalysis, focusing on multiarm star block polymers derived from vinyl-cyclohexene oxide (vCHO), CO2, and ε-decalactone (ε-DL). A [Zn(II)Mg(II)] organometallic catalyst and multifunctional chain-transfer agents (CTAs) are employed in a “core-first” approach to produce tri-, tetra-, and hexafunctional star block polymers. Thermomechanical and morphological properties were evaluated as a function of molar mass, number of arms, and architecture, indicating the differences between star and linear structures. Postpolymerization modification of the polycarbonate block, via thiol–ene chemistry, introduced pendant hydroxyl groups, enhancing hydrogen bonding and microphase separation, significantly impacting thermal and mechanical performance. This work highlights the versatility of switchable catalysis in accessing star polymers while underscoring the potential of integrating architectural control and functionalization to enhance the performance and applicability of CO2-derived poly(ester-b-carbonate)s.
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Oct 2025
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
E02-JEM ARM 300CF
I11-High Resolution Powder Diffraction
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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.
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Oct 2025
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