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Instruments / Technical Area	Publication Details	Published
I11-High Resolution Powder Diffraction I20-EDE-Energy Dispersive EXAFS (EDE)	Control of zeolite microenvironment for propene synthesis from methanol Longfei Lin , Mengtian Fan , Alena M. Sheveleva , Xue Han , Zhimou Tang , Joseph H. Carter , Ivan Da Silva , Christopher Parlett , Floriana Tuna , Eric J. L. Mcinnes , German Sastre , Svemir Rudic , Hamish Cavaye , Stewart F. Parker , Yongqiang Cheng , Luke L. Daemen , Anibal J. Ramirez-Cuesta , Martin P. Attfield , Yueming Liu , Chiu C. Tang , Buxing Han , Sihai Yang Nature Communications 12 DOI: 10.1038/s41467-021-21062-1 Diamond Proposal Number(s): [2359] Open Access Show Abstract ▼ Abstract: Optimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.	Feb 2021
I15-Extreme Conditions	High-pressure neutron powder diffraction study of ε-CL-20: A gentler way to study energetic materials Sumit Konar , Steven Hunter , Carole A. Morrison , Paul L. Coster , Helen Maynard-Casely , Jonathan G. Richardson , William G. Marshall , Annette Kleppe , Stewart F. Parker , Colin R. Pulham The Journal Of Physical Chemistry C DOI: 10.1021/acs.jpcc.0c09967 Diamond Proposal Number(s): [4631, 6707] Show Abstract ▼ Abstract: High-pressure studies have been performed on the ε-form of the powerful explosive CL-20. Hydrostatic compression over the pressure range 0–12 GPa has been monitored using synchrotron X-ray powder diffraction. The potential effects of X-ray radiation damage were observed and circumvented through a follow-up compression study over the pressure range 0–7 GPa using neutron powder diffraction. This second study revealed smooth compression behavior, and the absence of any phase transitions. Intermolecular interaction energies as obtained using PIXEL calculations did not show any discontinuity upon the application of pressure. An isothermal equation of state has been determined, and the high-pressure response is supported by dispersion-corrected density functional theory calculations. Inelastic neutron scattering (experimental and simulated) spectra for the ε-form are in excellent agreement.	Dec 2020
B18-Core EXAFS	Investigation of moOx/Al2O3 under cyclic operation for oxidative and non-oxidative dehydrogenation of propane Santhosh K. Matam , Caitlin Moffat , Pip Hellier , Michael Bowker , Ian P. Silverwood , C. Richard A. Catlow , S. David Jackson , James Craswell , Peter P. Wells , Stewart F. Parker , Emma K. Gibson Catalysts 10 DOI: 10.3390/catal10121370 Diamond Proposal Number(s): [10306] Open Access Show Abstract ▼ Abstract: A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species.	Nov 2020
B18-Core EXAFS	The application of inelastic neutron scattering to investigate iron-based Fischer-Tropsch to olefins catalysis Alisha L. Davidson , Emma K. Gibson , Giannantonio Cibin , Hendrik Van Rensburg , Stewart F. Parker , Paul B. Webb , David Lennon Journal Of Catalysis DOI: 10.1016/j.jcat.2020.09.025 Diamond Proposal Number(s): [15151, 18431] Open Access Show Abstract ▼ Abstract: The technique of inelastic neutron scattering (INS) is used to investigate how hydrogen is partitioned within a series of Na and S promoted iron-based Fischer-Tropsch-to-olefin catalysts. Two reaction test regimes are examined. First, reaction testing at elevated temperature and pressure demonstrate how Na/S additions enhance short chain olefin selectivity and reduce methane formation under industrially relevant reaction conditions. For a fixed level of Na incorporation (2000 ppm), sulfur concentrations of ≤ 100 ppm result in only a modest improvement in olefin selectivity. However, for sulfur values of ≥ 100 ppm there is a noticeable and systematic increase in C2-C4 olefin selectivity; rising from ∼30.0 % to 35.2% at 250 ppm. Second, using ambient pressure CO hydrogenation as a test reaction in INS and micro-reactor configurations, catalyst samples are further analysed by TPR, TPO, XRD and S K-edge XANES. INS shows the formation of a hydrocarbonaceous overlayer to be significantly attenuated by the presence of the promoters, with increasing S levels significantly reducing the intensity of the sp2 and sp3 hybridised ν(C-H) modes of the overlayer, albeit to differing degrees. A probable role for how this combination of promoters is perturbing the form of the hydrocarbonaceous overlayer to subsequently moderate the product distribution is considered.	Oct 2020
	Neutrons for cultural heritage - techniques, sensors, and detection Giulia Festa , Giovanni Romanelli , Roberto Senesi , Laura Arcidiacono , Claudia Scatigno , Stewart F. Parker , M. Paula M. Marques , Carla Andreani Sensors 20 DOI: 10.3390/s20020502 Open Access Show Abstract ▼ Abstract: Advances in research in Cultural Heritage see increasing application of a multidisciplinary approach and the combined use of physical and chemical characterization of artefacts that can be used to define their structure and their state of conservation, also providing valuable information in selecting the most suitable microclimatic conditions for the exhibition environment. This approach provides a platform for a synergic collaboration amongst researchers, restorers, conservators, and archaeologists. Existing state-of-the-art technologies for neutron-based methods are currently being applied to the study of objects of historical and cultural interest in several neutron-beam facilities around the world. Such techniques are non-invasive and non-destructive and are, therefore, ideal to provide structural information about artefacts, such as their composition, presence of alterations due to the environmental conditions, inclusions, structure of the bulk, manufacturing techniques, and elemental composition, which provide an overall fingerprint of the object's characteristics, thanks to the nature of the interaction of neutrons with matter. Here, we present an overview of the main neutron methods for the characterization of materials of interest in Cultural Heritage and we provide a brief introduction to the sensors and detectors that are used in this framework. We conclude with some case studies underlining the impact of these applications in different archaeological and historical contexts.	Jan 2020
B18-Core EXAFS	Deactivation of a single-site gold-on-carbon acetylene hydrochlorination catalyst: An X-ray absorption and inelastic neutron scattering study Grazia Malta , Simon A. Kondrat , Simon J. Freakley , Catherine Davies , Simon Dawson , Xi Liu , Li Lu , Krzysztof Dymkowski , Felix Fernandez-Alonso , Sanghamitra Mukhopadhyay , Emma Kate Gibson , Peter P. Wells , Stewart F. Parker , Christopher J. Kiely , Graham J. Hutchings Acs Catalysis DOI: 10.1021/acscatal.8b02232 Diamond Proposal Number(s): [10306, 11398, 15214] Open Access Show Abstract ▼ Abstract: Single-site Au species supported on carbon have been shown to be the active sites for acetylene hydrochlorination. The evolution of these single-site species has been monitored by Au L3 X-ray Absorption Spectroscopy (XAS). Alternating between a standard reaction mixture of HCl/C2H2 and the single reactants, has provided insights into the reaction mechanism and catalyst deactivation processes. We demonstrate that oxidative addition of HCl across an Au(I) chloride species requires concerted addition with C2H2, in accordance with both the XAS measurements of Au oxidation state and the reaction kinetics being 1st order with respect to each reactant. The addition of excess C2H2 changes the Au speciation and results in the formation of oligomeric acetylene species which were detected by inelastic neutron scattering. Catalyst deactivation at extended reaction times can be correlated with the formation of metallic Au particles. The presence of this Au(0) species generated during the sequential gas experiments or after prolonged reaction times, results in the analysis of the normalised near edge white line intensity of the Au L3 X-ray absorption spectrum alone becoming an unsuitable guide for identifying the active Au species, affecting the strong correlation between normalized white line height and VCM productivity usually observed in the active catalyst. Thus, a combination of scanning transmission electron microscopy and detailed modelling of whole XAS spectrum was required to distinguish active Au(I) and Au(III) species from the spectator Au(0) component.	Jul 2018
	Adsorption of formate species on Cu(h,k,l) low index surfaces Arunabhiram Chutia , Ian P. Silverwood , Matthew R. Farrow , David O. Scanlon , Peter P. Wells , Michael Bowker , Stewart F. Parker , C. Richard A. Catlow Surface Science 653, 45 - 54 DOI: 10.1016/j.susc.2016.05.002 Open Access Show Abstract ▼ Abstract: We report a density functional theory study on the relative stability of formate species on Cu(h,k,l) low index surfaces using a range of exchange-correlation functionals. We find that these functionals predict similar geometries for the formate molecule adsorbed on the Cu surface. A comparison of the calculated vibrational transition energies of a perpendicular configuration of formate on Cu surface shows an excellent agreement with the experimental spectrum obtained from inelastic neutron spectroscopy. From the calculations on adsorption energy we find that formate is most stable on the Cu(110) surface as compared to Cu(111) and Cu(100) surfaces. Bader analysis shows that this feature could be related to the higher charge transfer from the Cu(110) surface and optimum charge density at the interfacial region due to bidirectional electron transfer between the formate and the Cu surface. Analysis of the partial density of states finds that in the –5.5 eV to –4.0 eV region, hybridization between O p and the non-axial Cu dyz and dxz orbitals takes place on the Cu(110) surface, which is energetically more favourable than on the other surfaces.	Nov 2016
B18-Core EXAFS	A molecular view of cisplatin's mode of action: interplay with DNA bases and acquired resistance Paula M. Marques , Diego Gianolio , Giannantonio Cibin , John Tomkinson , Stewart Parker , Rosendo Valero , R. Pedro Lopes , Luis Batista De Carvalho Physical Chemistry Chemical Physics 17 (7), 5155 - 5171 DOI: 10.1039/C4CP05183A Diamond Proposal Number(s): [8434] Show Abstract ▼ Abstract: The interaction of the widely used anticancer drug cisplatin with DNA bases was studied by EXAFS and vibrational spectroscopy (FTIR, Raman and INS), coupled with DFT/plane-wave calculations. Detailed information was obtained on the local atomic structure around the Pt(II) centre, both in the cisplatinpurine (adenine and guanine) and cisplatinglutathione adducts. Simultaneous neutron and Raman scattering experiments allowed us to obtain a reliable and definite picture of this cisplatin interplay with its main pharmacological target (DNA), at the molecular level. The vibrational experimental spectra were fully assigned in the light of the calculated pattern for the most favoured geometry of each drugpurine adduct, and cisplatins preference for guanine (G) relative to adenine (A) within the DNA double helix was experimentally verified: a complete N by S substitution in the metal coordination sphere was only observed for [cDDPA2], reflecting a somewhat weaker PtA binding relative to PtG. The role of glutathione on the drugs pharmacokinetics, as well as on the stability of platinated DNA adducts, was evaluated as this is the basis for glutathione-mediated intracellular drug scavenging and in vivo resistance to Pt-based anticancer drugs. Spectroscopic evidence of the metals preference for glutathiones sulfur over purines nitrogen binding sites was gathered, at least two sulfur atoms being detected in platinums first coordination sphere.	Jan 2015
I11-High Resolution Powder Diffraction	Experimental and DFT-D studies of the molecular organic energetic material RDX Steven Hunter , Tuuli Sutinen , Stewart F. Parker , Carole A. Morrison , David M. Williamson , Stephen Thompson , Peter J. Gould , Colin R. Pulham The Journal Of Physical Chemistry C 117 (16) DOI: 10.1021/jp4004664 Show Abstract ▼ Abstract: We have performed simulations utilizing the dispersion-corrected density functional theory method (DFT-D) as parametrized by Grimme on selected polymorphs of RDX (cyclotrimethylenetrinitramine). Additionally, we present the first experimental determination of the enthalpy of fusion (ΔHfus) of the highly metastable β-form of RDX. The characteristics of fusion for β-RDX were determined to be 186.7 ± 0.8 °C, 188.5 ± 0.4 °C, and 12.63 ± 0.28 kJ mol–1 for the onset temperature, peak temperature (or melting point), and ΔHfus, respectively. The difference in experimental ΔHfus for the α- and β-forms of RDX is 20.46 ± 0.92 kJ mol–1. Ambient-pressure lattice energies (EL) of the α- and β-forms of RDX have been calculated and are in excellent agreement with experiment. In addition the computationally predicted difference in EL (20.35 kJ mol–1) between the α- and β-forms is in excellent agreement with the experimental difference in ΔHfus. The response of the lattice parameters and unit-cell volumes to pressure for the α- and γ-forms have been investigated, in addition to the first high-pressure computational study of the ε-form of RDX—these results are in very good agreement with experimental data. Phonon calculations provide good agreement for vibrational frequencies obtained from Raman spectroscopy, and a predicted inelastic neutron scattering (INS) spectrum of α-RDX shows excellent agreement with experimental INS data determined in this study. The transition energies and intensities are reproduced, confirming that both the eigenvalues and the eigenvectors of the vibrations are correctly described by the DFT-D method. The results of the high-pressure phonon calculations have been used to show that the heat capacities of the α-, γ-, and ε-forms of RDX are only weakly affected by pressure.	Mar 2013

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