B18-Core EXAFS
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Diamond Proposal Number(s):
[34632]
Abstract: Polychlorinated aromatic hydrocarbons (PCAHs) in flue gas seriously threaten the environment and human health, and Ru-based catalysts exhibit efficient oxidation property for PCAHs removal. However, the current Ru catalysts either have high Ru loading/non-stable structure or are developed empirically whilst lack of design mechanism. Herein, a robust Ru single atom catalyst (0.5 Ru1/TiO2) was designed based on metal-support interaction for o-DCB (o-dichlorobenzene, a typical PCAHs) degradation, and it revealed significantly better oxidation activity with T50 = 207.4 °C and T90 = 243.5 °C than its contrast with weak metal-support interaction (0.5 RuNP/TiO2, T50 = 247.4 °C, T90 > 300 °C). In addition, 0.5 Ru1/TiO2 exhibited much better chlorine resistance stability, maintaining >90% o-DCB conversion for 700 min versus∼70% on 0.5 RuNP/TiO2. The superior performance of 0.5 Ru1/TiO2 was attributed to its stronger metal-support interaction between Ru and TiO2, verified by H2-TPR, which offered higher active oxygen species (22.4%), more Lewis acid (0.675 mmol/g) and higher exposed Ru ratio (> 90.0%) than 0.5 RuNP/TiO2 (15.0%, 0.068 mmol/g, 28.6%, respectively). The above properties can not only enhance o-DCB adsorption/activation and weaken its Csingle bondCl bonds but also favor partial/deep oxidation and remove deposited chlorine on 0.5 Ru1/TiO2, proved by in situ FT-IR. Moreover, notable higher water resistance under different water vapor and applicability under varied pollutant concentration were observed on the robust Ru1/TiO2. This work reveals insightful function-property study on Ru single atom catalysts for PCAHs oxidative removal.
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May 2026
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B18-Core EXAFS
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Yingxiang
Zhao
,
Yingjie
Zhao
,
Xinyue
Zhou
,
Haiwei
Guo
,
Qiqi
Yin
,
Yutao
Jiang
,
Haiyan
He
,
Na
Liu
,
Gengbo
Ren
,
Christopher M. A.
Parlett
,
Changzhi
Li
Diamond Proposal Number(s):
[34632]
Abstract: M–N–C single-atom catalysts (SACs) represent promising candidates owing to their atomically dispersed active sites and tunable catalytic properties and have shown broad potential in various catalysis reactions. However, the mechanisms and true active sites involved in lignin conversion, particularly oxidative depolymerization, remain unclear. Herein, a Ru–N–C SAC with a well-defined configuration, including coordination environment and coordination number, was synthesized via a straightforward ball-milling method for lignin oxidation. The Ru–N–C SAC prepared with 12 h of ball milling demonstrated high catalytic performance in the oxidative depolymerization of various β-O-4 model compounds and diverse lignin feedstocks. Structural analysis via X-ray absorption spectroscopy demonstrated that the Ru–N4 motif constitutes the predominant coordination environment in Ru–N–C, which is regarded as the primary active site in activating O2 into superoxide radicals, as confirmed by free-radical quenching experiments and electron paramagnetic resonance analysis; meanwhile, it also served as a basic site in polarizing Cβ–H bonds in β-O-4 that favored C–O/C–C bond cleavage, which was disclosed by CO2 temperature-programmed desorption and electron localization function analysis. The critical role of Ru–N4 in the activation of O2 and C–O/C–C bond cleavage was further confirmed by density functional theory calculation, which indicated that the Ru–N4 center exhibits strong adsorption toward both the O2 and β-O-4 linkages. This work provides a deep understanding on the active sites within Ru–N–C SACs for lignin oxidative cleavage and offers great potential on the rational design of next-generation SACs in biomass valorization.
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Feb 2026
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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
I20-EDE-Energy Dispersive EXAFS (EDE)
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Wenyuan
Huang
,
Bing
An
,
Zeyu
Chen
,
Yu
Han
,
Yinlin
Chen
,
Jiangnan
Li
,
Xue
Han
,
Shaojun
Xu
,
Danielle
Crawshaw
,
Evan
Tillotson
,
Sarah J.
Haigh
,
Bing
Han
,
Christopher M. A.
Parlett
,
Luke
Keenan
,
Svemir
Rudic
,
Yongqiang
Cheng
,
Ben F.
Spencer
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[28575, 31729]
Open Access
Abstract: The development of earth-abundant metal-based catalysts is an important goal for the synthesis of fine chemicals. Here, an active nickel catalyst supported on a robust metal–organic framework, MFM-300(Cr), is reported which shows an exceptional performance for reductive amination, a reaction that has long been dominated by noble metals. Ni/MFM-300(Cr) promotes the synthesis of 38 primary amines via reductive amination of their parent carbonyl compounds, including biomass-derived aldehydes and ketones, using NH3 in the presence of H2 operating under relatively mild conditions (5 bar and 160 °C). X-ray absorption spectroscopy confirms the formation of mixtures of metallic Ni0 and Nin+ active sites, while in situ inelastic neutron scattering, coupled with modeling, reveals details of the mechanism of catalysis involving the formation of N-benzyl-1-phenylmethanediamine (BPDI) as an intermediate species in the generation of benzylamine. Cooperativity between Ni sites and MFM-300(Cr) creates an optimal microenvironment for the efficient activation of carbonyl compounds and the selective production of primary amines using a non-precious metal-based catalyst.
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Oct 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Mark A.
Isaacs
,
Charalampos
Drivas
,
Arthur
Graf
,
Sasha
Kroon
,
Santosh
Kumar
,
Junxi
Liu
,
Antonio
Torres‐lopez
,
Cameron
Price
,
Edward
Garland
,
Ines
Lezcano-Gonzalez
,
Christopher M. A.
Parlett
,
Vannia C.
Dos Santos-Durndell
,
Lee J.
Durndell
Diamond Proposal Number(s):
[40403]
Open Access
Abstract: 2.5% of global carbon emissions result from air travel, underscoring the need for sustainable aviation fuels (SAF) derived from second-generation lignocellulosic biomass to enhance the green credentials of the aviation sector. This study demonstrates the first solvent-free photocatalytic conversion of furfural (FAL) and cyclopentanone (CPO) to produce 2,5-bis(2-furylmethylidene)cyclopentanone (F2Cp), a jet fuel precursor, using Ti-SBA-15 catalysts, synthesized via alkoxide grafting and controlled titanium surface coverage. Sub-monolayer titania films on SBA-15 supports are achieved with tuneable Ti content, confirmed by XPS (X-ray photoelectron spectroscopy), UPS (ultraviolet photoelectron spectroscopy), REELS (reflectance electron energy loss spectroscopy), ISS (ion scattering spectroscopy), and Raman analysis. XPS analyses reveal coverage-dependent Ti speciation, transitioning from isolated Ti atoms to interconnected Ti-O-Ti networks, with corresponding shifts in Auger parameters, indicating increased surface polarizability and Lewis acidity. Optimized Ti-SBA-15 catalysts exhibit a fourfold activity enhancement in photocatalytic activity over bulk TiO₂, attributed to improved mass transport, active site accessibility, and surface stability. This work highlights the potential of rationally designed hierarchical catalysts for scalable, energy-efficient biomass valorization into SAF precursors, offering a scalable, energy-efficient pathway for sustainable jet fuel production. By elucidating the structure-function relationships in sub-monolayer Ti-SBA-15 materials, this study provides critical insights for advancing photocatalytic technologies in renewable energy applications.
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Jul 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[34632]
Abstract: Bimetallic palladium (Pd) and gold (Au) systems are active for promoting the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a key building block for producing polyethylene furanoate, a biobased polymer to substitute poly(ethylene terephthalate). Here, an FDCA yield of ∼99% was achieved over a physical mixture of 1.5 wt % Au/C and 1.5 wt % Pd/C (Pd/Au molar ratio of 5:1) under mild conditions (90 °C, 1 bar O2), outperforming bimetallic core–shell Au@Pd/C (∼90% FDCA yield) or alloyed AuPd/C (∼73% FDCA yield) systems. To gain insights into the synergy between the two monometallic catalysts, a series of kinetic studies were conducted employing either HMF or its intermediates as substrates in catalytic oxidation systems over either Pd/C or Au/C. The results show distinct selectivity preference of the two catalysts: Pd/C favors the 2,5-diformylfuran pathway (DFF), while Au/C follows the 5-hydroxymethyl-2-furancarboxylic acid (HFCA) pathway, as well as the presence of base-induced Cannizzaro disproportionation (CD) reactions. The advantage of the physical mixture system is largely attributed to the synergy between the two metals, which promotes the DFF pathway (over the HFCA route) and suppresses CD reactions, facilitating a more rapid progression of the overall oxidation cascade process. Catalyst recycling studies reveal deactivation of the physical mixture system (FDCA yield dropped to 62% after 3 cycles), with detailed comparative characterization of the fresh and used catalysts identifying operando Pd leaching and subsequent deposition onto Au/C, forming a core (Au)–shell (Pd) structure, as the origin of the diminished activity. Our findings challenge the conventional view regarding the alloy superiority in the selective oxidation of HMF, showing that systems based on simple physical mixtures of monometallic catalysts could be a more effective and practical strategy for progressing FDCA production via selective HMF oxidation.
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Jun 2025
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Open Access
Abstract: Furfural (Fur) represents an interesting bio-based platform chemical to pave the way to enhanced biorefinery integration in the modern chemicals industry. The production of this xylose- derived compound by its dehydration is catalysed by Brønsted acidity and has effectively been performed in biphasic systems using methyl isobutyl ketone (MIBK), where furfural is effectively partitioned. A selection of commercially available solid-acid catalysts were evaluated (different ion exchange resins, zeolites and sulfated zirconia), with top candidates being subjected to recycling experiments over six runs with carbon deposition removal and acid site regeneration. A sulfated zirconia (SO2/ZrO2-1) catalyst proved effective with maximum yield of Fur of 53.8% after 180 mins at 160 °C, with xylose conversion of 98.4%. A phenomenological approach to model developments was employed to describe the formation of each component of the reaction scheme and distribution in a biphasic system, with 18 separate kinetic models including both homo- and heterogeneous reaction pathways reported. The most optimal model, identified through statistical model discrimination (RMSE = 0.088), was a pseudohomogenous model with first order reaction kinetics for xylose conversion to Fur via a reactive intermediate and second order with respect to humin formation. Apparent activation energies for xylose dehydration were reported at 44.70 ± 7.89 kJ mol-−1, with results stating the formation of Fur proceeded preferentially through this reactive intermediate.
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Jan 2025
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Shengzhe
Ding
,
Dario Luis
Fernandez Ainaga
,
Min
Hu
,
Boya
Qiu
,
Ushna
Khalid
,
Carmine
D’agostino
,
Xiaoxia
Ou
,
Ben
Spencer
,
Xiangli
Zhong
,
Yani
Peng
,
Nicole
Hondow
,
Constantinos
Theodoropoulos
,
Yilai
Jiao
,
Christopher
Parlett
,
Xiaolei
Fan
Open Access
Abstract: Spatial control over features within multifunctional catalysts can unlock efficient one-pot cascade reactions, which are themselves a pathway to aviation biofuels via hydrodeoxygenation. A synthesis strategy that encompasses spatial orthogonality, i.e., one in which different catalytic species are deposited exclusively within discrete locations of a support architecture, is one solution that permits control over potential interactions between different sites and the cascade process. Here, we report a Pd doped hierarchical zeolite, in which Pd nanoparticles are selectively deposited within the mesopores, while acidity is retained solely within the micropores of ZSM-5. This spatial segregation facilitates hydrodeoxygenation while suppressing undesirable decarboxylation and decarbonation, yielding significant enhancements in activity (30.6 vs 3.6 moldodecane molPd−1 h−1) and selectivity (C12:C11 5.2 vs 1.9) relative to a conventionally prepared counterpart (via wet impregnation). Herein, multifunctional material design can realise efficient fatty acid hydrodeoxygenation, thus advancing the field and inspiring future developments in rationalised catalyst design.
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Sep 2024
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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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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
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Elizabeth
Jones
,
Charalampos
Drivas
,
Joshua
Gibson
,
Jack
Swallow
,
Leanne
Jones
,
Thomas
Bricknell
,
Matthijs
Van Spronsen
,
Georg
Held
,
Mark
Isaacs
,
Christopher
Parlett
,
Robert S.
Weatherup
Diamond Proposal Number(s):
[30358]
Open Access
Abstract: Environmental cells sealed with photoelectron-transparent graphene windows are promising for extending X-ray photoelectron spectroscopy (XPS) to liquid and high-pressure gas environments for in situ and operando studies. However, the reliable production of graphene windows that are sufficiently leak-tight for extended measurements remains a challenge. Here we demonstrate a PDMS/Au(100 nm)-supported transfer method that reliably produces suspended graphene on perforated silicon nitride membranes without significant contamination. A yield of ~95% is achieved based on single-layer graphene covering >98% of the holes in the silicon nitride membrane. Even higher coverages are achieved for stacked bilayer graphene, allowing wet etching (aqueous KI/I2) of the Au support to be observed in a conventional lab-based XPS system, thereby demonstrating the in situ formation of leak-tight, suspended graphene windows. Furthermore, these windows allow gas-phase measurements at close to atmospheric pressure, showing future promise for XPS under higher-pressure gas environments in conventional lab-based systems.
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Apr 2024
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