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Instruments / Technical Area	Publication Details	Published
I11-High Resolution Powder Diffraction	Crystal structure and stoichiometric composition of potassium-intercalated tetracene Craig I. Hiley , Kenneth K. Inglis , Marco Zanella , Jiliang Zhang , Troy D. Manning , Matthew S. Dyer , Tilen Knaflič , Denis Arčon , Frédéric Blanc , Kosmas Prassides , Matthew J. Rosseinsky Inorganic Chemistry DOI: 10.1021/acs.inorgchem.0c01635 Open Access Show Abstract ▼ Abstract: The products of the solid-state reactions between potassium metal and tetracene (K:Tetracene, 1:1, 1.5:1, and 2:1) are fully structurally characterized. Synchrotron X-ray powder diffraction shows that only K2Tetracene forms under the reaction conditions studied, with unreacted tetracene always present for x < 2. Diffraction and 13C MAS NMR show that K2Tetracene has a crystal structure that is analogous to that of K2Pentacene, but with the cations ordered on two sites because of the influence of the length of the hydrocarbon on possible cation positions. K2Tetracene is a nonmagnetic insulator, thus further questioning the nature of reported superconductivity in this class of materials.	Aug 2020
B18-Core EXAFS	Incorporation of Sb 5+ into CeO2 : local structural distortion of the fluorite structure from a pentavalent substituent Craig I. Hiley , Janet M. Fisher , Reza J. Kashtiban , Giannantonio Cibin , David Thompsett , Richard I. Walton Dalton Transactions 56 DOI: 10.1039/C8DT01750F Diamond Proposal Number(s): [5828, 7253] Show Abstract ▼ Abstract: Hydrothermal crystallisation of CeO2 from aqueous sodium hydroxide solution at 240 °C using CeCl3·7H2O in the presence of hydrogen peroxide with addition of either SbCl3 or SbCl5 yields polycrystalline samples of antimony-containing ceria directly from solution. Powder X-ray diffraction shows a contraction of the cubic lattice parameter with increasing Sb content, and also a broadening of Bragg peaks, from which Scherrer analysis yields crystallite domain sizes of 5–20 nm. Scanning transmission electron microscopy provides consistent results with observation of highly crystalline particles of a few nm in diameter. X-ray absorption near edge structure spectroscopy at the Ce LIII- and Sb K-edges reveals the presence of Ce4+ and Sb5+ in the solids. To balance charge the presence of co-included Na is proposed, corroborated by elemental analysis. The general chemical formula of the materials can thus be written as (Ce1−xSbx)1−yNayO2−δ (where x < 0.4 and y ≥ x/3). Sb K-edge extended X-ray absorption fine structure spectroscopy of the substituted ceria samples shows that the local structure of Sb resembles that in NaSbO3, where six-coordinate metal sites are found, but with evidence of a longer interatomic correlation due to surrounding Ce/Sb atoms in the fluorite structure; this implies that the Sb is displaced from the ideal eight-coordinate site of the fluorite structure. This structural distortion gives materials that are unstable under reducing conditions, coupled by the ease of reduction to elemental antimony, which is extruded leading to phase separation.	Jun 2018
B18-Core EXAFS	Pair distribution function analysis of structural disorder by nb5+inclusion in ceria: evidence for enhanced oxygen storage capacity from under-coordinated oxide Craig I. Hiley , Helen Playford , Janet M. Fisher , Noelia Cortes Felix , David Thompsett , Reza J. Kashtiban , Richard I. Walton Journal Of The American Chemical Society DOI: 10.1021/jacs.7b12421 Diamond Proposal Number(s): [8708] Show Abstract ▼ Abstract: Partial substitution of Ce4+ by Nb5+ is possible in CeO2 by co-inclusion of Na+ to balance the charge, via hydrothermal synthesis in sodium hydroxide solution. Pair distribution function analysis using reverse Monte Carlo refinement reveals that the small pentavalent substituent resides in irregular coordination positions in an average fluorite lattice, displaced away from the ideal cubic coordination towards four oxygens. This results in under-coordinated oxygen, which explains significantly enhanced oxygen storage capacity of the materials of relevance to redox catalysis used in energy and environmental applications.	Jan 2018
I11-High Resolution Powder Diffraction	Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids Fabio Denis Romero , Michael Pitcher , Craig Hiley , George Whitehead , Srotoswini Kar , Alexey Ganin , Dmitro Antypov , Christopher Collins , Matthew Dyer , Gyongyi Klupp , Ross Colman , Kosmas Prassides , Matthew Rosseinsky Nature Chemistry DOI: 10.1038/nchem.2765 Diamond Proposal Number(s): [9282, 12336] Show Abstract ▼ Abstract: Alkali metal intercalation into polyaromatic hydrocarbons (PAHs) has been studied intensely after reports of superconductivity in a number of potassium- and rubidium-intercalated materials. There are, however, no reported crystal structures to inform our understanding of the chemistry and physics because of the complex reactivity of PAHs with strong reducing agents at high temperature. Here we present the synthesis of crystalline K2Pentacene and K2Picene by a solid–solid insertion protocol that uses potassium hydride as a redox-controlled reducing agent to access the PAH dianions, and so enables the determination of their crystal structures. In both cases, the inserted cations expand the parent herringbone packings by reorienting the molecular anions to create multiple potassium sites within initially dense molecular layers, and thus interact with the PAH anion π systems. The synthetic and crystal chemistry of alkali metal intercalation into PAHs differs from that into fullerenes and graphite, in which the cation sites are pre-defined by the host structure.	Apr 2017
B18-Core EXAFS	Ba4Ru3O10.2(OH)1.8: a new member of the layered hexagonal perovskite family crystallised from water Craig Hiley , Martin Lees , David L. Hammond , Reza J. Kashtiban , Jeremy Sloan , Ronald I. Smith , Richard Walton Chemical Communications DOI: 10.1039/C6CC02121B Diamond Proposal Number(s): [7646] Show Abstract ▼ Abstract: A new barium ruthenium oxyhydroxide Ba4Ru3O10.2(OH)1.8 crystallises under hydrothermal conditions at 200 °C: powder neutron diffraction data show it adopts an 8H hexagonal perovskite structure with a new stacking sequence, while high resolution electron microscopy reveals regions of ordered layers of vacant Ru sites, and magnetometry shows antiferromagnetism with TN = 200(5) K.	Apr 2016
	Antiferromagnetism at T>500K in the layered hexagonal ruthenate SrRu2O6 C. I. Hiley , D. O. Scanlon , A. A. Sokol , S. M. Woodley , A. M. Ganose , S. Sangiao , J. M. De Teresa , P. Manuel , D. D. Khalyavin , M. Walker , M. R. Lees , R. I. Walton Physical Review B 92 DOI: 10.1103/PhysRevB.92.104413 Show Abstract ▼ Abstract: We report an experimental and computational study of the magnetic and electronic properties of the layered Ru(V) oxide SrRu2O6 (hexagonal, P31¯ m), which shows antiferromagnetic order with a Neel temperature of ´ 563(2) K, among the highest for 4d oxides. Magnetic order occurs both within edge-shared octahedral sheets and between layers and is accompanied by anisotropic thermal expansivity that implies strong magnetoelastic coupling of Ru(V) centers. Electrical transport measurements using focused-ion-beam–induced deposited contacts on a micron-scale crystallite as a function of temperature show p-type semiconductivity. The calculated electronic structure using hybrid density functional theory successfully accounts for the experimentally observed magnetic and electronic structure, and Monte Carlo simulations reveal how strong intralayer as well as weaker interlayer interactions are a defining feature of the high-temperature magnetic order in the material.	Sep 2015
B18-Core EXAFS	Incorporation of square-planar Pd Craig Hiley , Janet M. Fisher , David Thompsett , Reza J. Kashtiban , Jeremy Sloan , Richard Walton Journal Of Materials Chemistry A 3 (24), 13072 - 13079 DOI: 10.1039/C5TA02007G Diamond Proposal Number(s): [8708] Open Access Show Abstract ▼ Abstract: The direct hydrothermal crystallisation at 240 °C of Pd2+-containing ceria is investigated to study the extent to which precious metal dopants may be introduced into the cubic fluorite lattice. Samples of composition Ce1−xPdxO2−δ, where 0 ≤ x ≤ 0.15 can be produced in which Pd is included within the CeO2 structure to give a linear lattice expansion. Attempts to produce higher Pd2+-substitution result in the formation of PdO as a secondary phase. Ce and Pd were determined to be in the +4 and +2 oxidation states, respectively, by X-ray absorption near edge structure, suggesting oxide deficiency as the mechanism of charge balance. Extended X-ray absorption fine structure (EXAFS) analysis at the Pd K-edge reveals that Pd2+ has local square-planar coordination, as expected, and that a structural model can fitted in which the average fluorite structure is maintained, but with Pd2+ sitting in the square faces of oxide ions present in the local cubic geometry of Ce. This model, consistent with previous modelling studies, gives an excellent fit to the EXAFS spectra, and explains the observed lattice expansion. Transmission electron microscopy analysis shows that Pd is well dispersed in the nanocrystalline ceria particles, and in situ powder XRD shows that upon heating in air the samples remain stable up to 800 °C. H2-TPR shows that Pd-substitution leads to low temperature (<200 °C) reduction of the oxide, which increases in magnitude with increasing Pd-substitution. On prolonged heating, however, the Pd is lost from the ceria lattice to give dispersed Pd metal, suggesting an inherent instability of Pd-doped CeO2.	May 2015
B18-Core EXAFS	Water-splitting electrocatalysis in acid conditions using ruthenate-iridate pyrochlores Kripasindhu Sardar , Enrico Petrucco , Craig Hiley , Jonathan D. B. Sharman , Peter Wells , Andrea Russell , Reza J. Kashtiban , Jeremy Sloan , Richard Walton Angewandte Chemie International Edition 53 (41), 10960 - 10964 DOI: 10.1002/anie.201406668 PMID: 25196322 Diamond Proposal Number(s): [7646] Open Access Show Abstract ▼ Abstract: The pyrochlore solid solution (Na0.33Ce0.67)2(Ir1−xRux)2O7 (0≤x≤1), containing B-site RuIV and IrIV is prepared by hydrothermal synthesis and used as a catalyst layer for electrochemical oxygen evolution from water at pH<7. The materials have atomically mixed Ru and Ir and their nanocrystalline form allows effective fabrication of electrode coatings with improved charge densities over a typical (Ru,Ir)O2 catalyst. An in situ study of the catalyst layers using XANES spectroscopy at the Ir LIII and Ru K edges shows that both Ru and Ir participate in redox chemistry at oxygen evolution conditions and that Ru is more active than Ir, being oxidized by almost one oxidation state at maximum applied potential, with no evidence for ruthenate or iridate in +6 or higher oxidation states.	Oct 2014
B18-Core EXAFS I11-High Resolution Powder Diffraction	Ruthenium(V) oxides from low-temperature hydrothermal synthesis Craig I. Hiley , Martin R. Lees , Janet M. Fisher , David Thompsett , Stefano Agrestini , Ronald I. Smith , Richard Walton Angewandte Chemie International Edition 53 (17), 4423 - 4427 DOI: 10.1002/anie.201310110 PMID: 24644102 Diamond Proposal Number(s): [7253] Show Abstract ▼ Abstract: Low-temperature (200 °C) hydrothermal synthesis of the ruthenium oxides Ca1.5Ru2O7, SrRu2O6, and Ba2Ru3O9(OH) is reported. Ca1.5Ru2O7 is a defective pyrochlore containing RuV/VI; SrRu2O6 is a layered RuV oxide with a PbSb2O6 structure, whilst Ba2Ru3O9(OH) has a previously unreported structure type with orthorhombic symmetry solved from synchrotron X-ray and neutron powder diffraction. SrRu2O6 exhibits unusually high-temperature magnetic order, with antiferromagnetism persisting to at least 500 K, and refinement using room temperature neutron powder diffraction data provides the magnetic structure. All three ruthenates are metastable and readily collapse to mixtures of other oxides upon heating in air at temperatures around 300–500 °C, suggesting they would be difficult, if not impossible, to isolate under conventional high-temperature solid-state synthesis conditions.	Apr 2014

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