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432 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5, 6, 7, 8 [Next/Last]

Instruments / Technical Area	Publication Details	Published
B18-Core EXAFS	Mild hydrogenolysis of lignin model compound and organosolv lignin over non-noble bimetallic Ni–Fe/TiN catalyst Tang Son Nguyen , Manh Tu Le , Van Hieu Nguyen Biomass And Bioenergy 174 DOI: 10.1016/j.biombioe.2023.106821 Diamond Proposal Number(s): [15151] Show Abstract ▼ Abstract: Lignin is one of the most promising feedstocks for renewable aromatics production. Conversion of such feedstock into aromatics can be attained through catalytic hydrogenolysis. In this work, NixFey/TiN bimetallic catalysts were evaluated in the hydrogenolysis of both: (i) benzyl phenyl ether (BPE) as a model compound for lignin and (ii) real organosolv lignin feedstock under low temperature (150 °C) and low H2 pressure (12 bar). All bimetallic catalysts exhibited superior performance over single-component materials and were shown to compose of uniformly/highly dispersed and intimately mixed Ni and Fe nanoparticles. Among bimetallic materials, Ni5Fe2/TiN possesses the highest activity in BPE hydrogenolysis, which is comparable to that of a 5% Pd/C commercial catalyst while showing significantly higher aromatic selectivity. Ni5Fe2/TiN catalyst also outperformed Pd/C in hydrogenolysis of organosolv lignin, shown by its higher oil yield, greater content of phenolic monomers, and lower content of dimers. This material exhibited good stability in BPE conversion with no noticeable deactivation over 5 recycling cycles. XANES analysis suggests the electron transfer from Ni to Fe, which explains the superior activity observed with Ni5Fe2/TiN.	Jul 2023
B18-Core EXAFS	Complex magnetic ordering behavior in the frustrated perovskite Ba2MnMoO6 Fiona C. Coomer , Heather M. Mutch , Otto Mustonen , Charlotte Pughe , Serena A. Cussen , Silvia Ramos , Adrian D. Hillier , Edmund J. Cussen Apl Materials 11 DOI: 10.1063/5.0144719 Open Access Show Abstract ▼ Abstract: New and exotic ground states of magnetic materials are highly sought after and are extensively studied for the insights they provide into the thermodynamics of disorder and fundamental magnetic interactions. By controlling the crystal structure of an appropriate magnetic lattice, it is possible to cause the strong magnetic exchange interactions to sum to zero and so be frustrated. Due to the presence of this frustration, the lowest energy configuration that results may be crucially dependent on the tiniest of energy differences between a multitude of states that have (almost) the same energy. The keen interest in these materials arises from the fact that these finely balanced systems offer a way of probing classical or quantum mechanical interactions that are of fundamental importance but are too weak to be observed in non-frustrated systems. Here, we combine local and crystallographic probes of the cation-ordered double perovskite Ba2MnMoO6 that contains a face-centered cubic lattice of S = 5/2 Mn2+ cations. Neutron diffraction measurements below 9.27(7) K indicate that a fourfold degenerate non-collinear antiferromagnetic state exists with almost complete ordering of the Mn2+ spins. Muon spin relaxation measurements provide a local probe of the magnetic fields inside this material over the t1/2 = 2.2 µs lifetime of a muon, indicating a slightly lower Néel transition temperature of 7.9(1) K. The dc susceptibility data do not show the loss of magnetization that should accompany the onset of the antiferromagnetic order; they indicate that a strongly antiferromagnetically coupled paramagnetic state [θ = −73(3) K] persists down to 4 K, at which temperature a weak transition occurs. The behavior of this material differs considerably from the closely related compositions Ba2MnMO6 (M = W, Te), which show collinear ordering arrangements and well defined antiferromagnetic transitions in the bulk susceptibility. This suggests that the Mo6+ cation leads to a fine balance between the nearest and next-nearest neighbor superexchange in these frustrated double perovskite structures.	May 2023
B18-Core EXAFS E01-JEM ARM 200CF	Isolated PdO sites on SiO2-supported NiO nanoparticles as active sites for allylic alcohol selective oxidation Aleksandra Ziarko , Thomas J. A. Slater , Mark A. Isaacs , Lee J. Durndell , Christopher M. A. Parlett Catalysis Science & Technology 40 DOI: 10.1039/D3CY00198A Diamond Proposal Number(s): [21795, 15151] Open Access Show Abstract ▼ Abstract: Catalytic allylic alcohol oxidation to aldehydes is an industrial process that necessitates chemoselectivity. Surface PdO (on Pd) enables this transformation but does not represent optimal metal utilisation. Here we report a facile synthesis route to produce isolated surface PdO catalytic sites on an earth-abundant metal (NiO) for cinnamyl alcohol oxidation.	May 2023
B18-Core EXAFS	Efficient low-loaded ternary Pd-In2O3-Al2O3 catalysts for methanol production Nicola Schiaroli , Leila Negahdar , Mads Lützen , Phuoc Hoang Ho , Lisa J. Allen , Alejandro Natoli , Francesca Ospitali , Francesco Maluta , Enrique Rodríguez-Castellón , Christian D. Damsgaard , Giuseppe Fornasari , Andrew M. Beale , Patricia Benito Journal Of Catalysis 371 DOI: 10.1016/j.jcat.2023.05.012 Show Abstract ▼ Abstract: Pd-In2O3 catalysts are among the most promising alternatives to Cu-ZnO-Al2O3 for synthesis of CH3OH from CO2. However, the intrinsic activity and stability of In2O3 per unit mass should be increased to reduce the content of this scarcely available element and to enhance the catalyst lifetime. Herein, we propose and demonstrate a strategy for obtaining highly dispersed Pd and In2O3 nanoparticles onto an Al2O3 matrix by a one-step coprecipitation followed by calcination and activation. The activity of this catalyst is comparable with that of a Pd-In2O3 catalyst (0.52 vs. 0.55 gMeOH h-1 gcat-1 at 300°C, 30 bar, 40,800 ml h-1 gcat-1) but the In2O3 loading decreases from 98 to 12 wt.% while improving the long-term stability by three-fold at 30 bar. In the new Pd-In2O3-Al2O3 system, the intrinsic activity of In2O3 is highly increased both in terms of STY normalized to In specific surface area and In2O3 mass (4.32 vs 0.56 g gMeOH h-1 gIn2O3-1 of a Pd- In2O3 catalyst operating at 300°C, 30 bar, 40,800 ml h-1 gcat-1).The combination of ex situ and in situ catalyst characterizations during reduction provides insights into the interaction between Pd and In and with the support. The enhanced activity is likely related to the close proximity of Pd and In2O3, wherein the H2 splitting activity of Pd promotes, in combination with CO2 activation over highly dispersed In2O3 particles, facile formation of CH3OH.	May 2023
B16-Test Beamline DIAD-Dual Imaging and Diffraction Beamline E01-JEM ARM 200CF E02-JEM ARM 300CF I08-Scanning X-ray Microscopy beamline (SXM) I12-JEEP: Joint Engineering, Environmental and Processing I13-1-Coherence I13-2-Diamond Manchester Imaging I14-Hard X-ray Nanoprobe	Synchrotron X-ray studies of the structural and functional hierarchies in mineralised human dental enamel: a state-of-the-art review Cyril Besnard , Ali Marie , Sisini Sasidharan , Robert A. Harper , Richard M. Shelton , Gabriel Landini , Alexander M. Korsunsky Dentistry Journal 11 DOI: 10.3390/dj11040098 Open Access Show Abstract ▼ Abstract: Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical–chemical–structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.	Apr 2023
B18-Core EXAFS	Interfacial chemistry in the electrocatalytic hydrogenation of CO2 over C-supported Cu-based systems Diego Gianolio , Michael D. Higham , Matthew G. Quesne , Matteo Aramini , Ruoyu Xu , Alex I. Large , Georg Held , Juan-Jesús Velasco-Vélez , Michael Haevecker , Axel Knop-Gericke , Chiara Genovese , Claudio Ampelli , Manfred Erwin Schuster , Siglinda Perathoner , Gabriele Centi , C. Richard A. Catlow , Rosa Arrigo Acs Catalysis DOI: 10.1021/acscatal.3c01288 Diamond Proposal Number(s): [24919] Open Access Show Abstract ▼ Abstract: Operando soft and hard X-ray spectroscopic techniques were used in combination with plane-wave density functional theory (DFT) simulations to rationalize the enhanced activities of Zn-containing Cu nanostructured electrocatalysts in the electrocatalytic CO2 hydrogenation reaction. We show that at a potential for CO2 hydrogenation, Zn is alloyed with Cu in the bulk of the nanoparticles with no metallic Zn segregated; at the interface, low reducible Cu(I)–O species are consumed. Additional spectroscopic features are observed, which are identified as various surface Cu(I) ligated species; these respond to the potential, revealing characteristic interfacial dynamics. Similar behavior was observed for the Fe–Cu system in its active state, confirming the general validity of this mechanism; however, the performance of this system deteriorates after successive applied cathodic potentials, as the hydrogen evolution reaction then becomes the main reaction pathway. In contrast to an active system, Cu(I)–O is now consumed at cathodic potentials and not reversibly reformed when the voltage is allowed to equilibrate at the open-circuit voltage; rather, only the oxidation to Cu(II) is observed. We show that the Cu–Zn system represents the optimal active ensembles with stabilized Cu(I)–O; DFT simulations rationalize this observation by indicating that Cu–Zn–O neighboring atoms are able to activate CO2, whereas Cu–Cu sites provide the supply of H atoms for the hydrogenation reaction. Our results demonstrate an electronic effect exerted by the heterometal, which depends on its intimate distribution within the Cu phase and confirms the general validity of these mechanistic insights for future electrocatalyst design strategies.	Apr 2023
B18-Core EXAFS	The hydrogenation of crotonaldehyde on PdCu single atom alloy catalysts Mohammed J. Islam , Marta Granollers Mesa , Amin Osatiashtiani , Martin J. Taylor , Mark A. Isaacs , Georgios Kyriakou Nanomaterials 13 DOI: 10.3390/nano13081434 Diamond Proposal Number(s): [19850] Open Access Show Abstract ▼ Abstract: Recyclable PdCu single atom alloys supported on Al2O3 were applied to the selective hydrogenation of crotonaldehyde to elucidate the minimum number of Pd atoms required to facilitate the sustainable transformation of an α,β-unsaturated carbonyl molecule. It was found that, by diluting the Pd content of the alloy, the reaction activity of Cu nanoparticles can be accelerated, enabling more time for the cascade conversion of butanal to butanol. In addition, a significant increase in the conversion rate was observed, compared to bulk Cu/Al2O3 and Pd/Al2O3 catalysts when normalising for Cu and Pd content, respectively. The reaction selectivity over the single atom alloy catalysts was found to be primarily controlled by the Cu host surface, mainly leading to the formation of butanal but at a significantly higher rate than the monometallic Cu catalyst. Low quantities of crotyl alcohol were observed over all Cu-based catalysts but not for the Pd monometallic catalyst, suggesting that it may be a transient species converted immediately to butanol and or isomerized to butanal. These results demonstrate that fine-tuning the dilution of PdCu single atom alloy catalysts can leverage the activity and selectivity enhancement, and lead to cost-effective, sustainable, and atom-efficient alternatives to monometallic catalysts.	Apr 2023
B18-Core EXAFS	Mo and W carbide catalysts - An approach towards sustainable conversions Marlene Führer Show Abstract ▼ Abstract: Catalysts play an important role in the shift from fossil-based chemical industry to a more sustainable, bio-based industry. Current used catalysts are noble metals like platinum or gold. However, noble metals are scarce, hence expensive, which makes it desirable to find more abundant alternatives. In this thesis, we focused on the production of new catalysts based on abundant materials for the conversion of bio-based feedstocks. (Mixed) molybdenum and tungsten carbide catalysts were used as alternatives for noble-based catalysts.	Apr 2023
B18-Core EXAFS	Largely pseudocapacitive two-dimensional conjugated metal–organic framework anodes with lowest unoccupied molecular orbital localized in nickel-bis(dithiolene) linkages Panpan Zhang , Mingchao Wang , Yannan Liu , Yubin Fu , Mingming Gao , Gang Wang , Faxing Wang , Zhiyong Wang , Guangbo Chen , Sheng Yang , Youwen Liu , Renhao Dong , Minghao Yu , Xing Lu , Xinliang Feng Journal Of The American Chemical Society 15 DOI: 10.1021/jacs.2c12684 Show Abstract ▼ Abstract: Although two-dimensional conjugated metal–organic frameworks (2D c-MOFs) provide an ideal platform for precise tailoring of capacitive electrode materials, high-capacitance 2D c-MOFs for non-aqueous supercapacitors remain to be further explored. Herein, we report a novel phthalocyanine-based nickel-bis(dithiolene) (NiS4)-linked 2D c-MOF (denoted as Ni2[CuPcS8]) with outstanding pseudocapacitive properties in 1 M TEABF4/acetonitrile. Each NiS4 linkage is disclosed to reversibly accommodate two electrons, conferring the Ni2[CuPcS8] electrode a two-step Faradic reaction with a record-high specific capacitance among the reported 2D c-MOFs in non-aqueous electrolytes (312 F g–1) and remarkable cycling stability (93.5% after 10,000 cycles). Multiple analyses unveil that the unique electron-storage capability of Ni2[CuPcS8] originates from its localized lowest unoccupied molecular orbital (LUMO) over the nickel-bis(dithiolene) linkage, which allows the efficient delocalization of the injected electrons throughout the conjugated linkage units without inducing apparent bonding stress. The Ni2[CuPcS8] anode is used to demonstrate an asymmetric supercapacitor device that delivers a high operating voltage of 2.3 V, a maximum energy density of 57.4 Wh kg–1, and ultralong stability over 5000 cycles.	Mar 2023
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS B18-Core EXAFS	Dispersed surface Ru ensembles on MgO(111) for catalytic ammonia decomposition Huihuang Fang , Simson Wu , Tugce Ayvali , Jianwei Zheng , Joshua Fellowes , Ping-Luen Ho , Kwan Chee Leung , Alexander Large , Georg Held , Ryuichi Kato , Kazu Suenaga , Yves Ira A. Reyes , Ho Viet Thang , Hsin-Yi Tiffany Chen , Shik Chi Edman Tsang Nature Communications 14 DOI: 10.1038/s41467-023-36339-w Open Access Show Abstract ▼ Abstract: Ammonia is regarded as an energy vector for hydrogen storage, transport and utilization, which links to usage of renewable energies. However, efficient catalysts for ammonia decomposition and their underlying mechanism yet remain obscure. Here we report that atomically-dispersed Ru atoms on MgO support on its polar (111) facets {denoted as MgO(111)} show the highest rate of ammonia decomposition, as far as we are aware, than all catalysts reported in literature due to the strong metal-support interaction and efficient surface coupling reaction. We have carefully investigated the loading effect of Ru from atomic form to cluster/nanoparticle on MgO(111). Progressive increase of surface Ru concentration, correlated with increase in specific activity per metal site, clearly indicates synergistic metal sites in close proximity, akin to those bimetallic N2 complexes in solution are required for the stepwise dehydrogenation of ammonia to N2/H2, as also supported by DFT modelling. Whereas, beyond surface doping, the specific activity drops substantially upon the formation of Ru cluster/nanoparticle, which challenges the classical view of allegorically higher activity of coordinated Ru atoms in cluster form (B5 sites) than isolated sites.	Feb 2023

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