I11-High Resolution Powder Diffraction
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Open Access
Abstract: The first reported phase in the Y2O3–NiO–TiO2 chemical space, the Y2NiTiO6 perovskite undergoes a temperature-induced order–disorder transition. Above ∼1700 K, it adopts the structure of a disordered CaTiO3-type orthorhombic perovskite with a = 5.26939(2), b = 5.60367(2), and c = 7.58137(3) Å, with the B site uniformly occupied by 0.5Ni+0.5Ti. Below this temperature, Y2NiTiO6 adopts rock-salt ordering of the transition metals in a monoclinic unit cell (a = 5.26695(2), b = 5.60164(2), c = 7.57493(2) Å, β = 90.4940(2)°) with 0.9/0.1 ordering of the B site. Ordering of Ni and Ti changes the magnetic properties from spin-glass behavior in the orthorhombic phase to antiferromagnetic order (TN = 17 K) for the monoclinic phase, while the optical properties of both phases remain unchanged across the transition.
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Oct 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[31218]
Open Access
Abstract: Several classes of inorganic transparent conducting coatings are available (broad band wide band gap semiconductors, noble metals, amorphous oxides and correlated metals), with peak performance depending on the layer thickness. Correlated metallic transition metal oxides have emerged as potential competitive materials for small coating thicknesses, but their peak performance remains one order of magnitude below other best in class materials. By exploiting the charge transfer at the interface between a correlated metal (SrNbO3) and a wide band gap semiconductor (SrTiO3), we show that pulsed laser deposition-grown SrNbO3 heterostructures on SrTiO3 outperform correlated metals by an order of magnitude. The apparent increase in carrier concentration confirms that an electronically active interfacial layer is contributing to the transport properties of the heterostructure. The correlated metallic electrode allows the extraction of high mobility carriers resulting in an enhanced conductivity for heterostructures with thicknesses up to 20 nm. The high optical absorption of the high mobility metallic interface does not have a detrimental effect on the transmission of the heterostructure due to its small thickness. The charge transfer-driven enhanced electrical properties in correlated metal - wide band gap semiconductor heterostructures offer a distinct route to high performance transparent conducting materials.
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May 2025
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I11-High Resolution Powder Diffraction
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Matthew J.
Rosseinsky
,
Moinak
Dutta
,
Angelos B.
Canaj
,
Tilen
Knaflič
,
Christopher M.
Collins
,
Troy D.
Manning
,
Hongjun
Niu
,
Luke M.
Daniels
,
Aikaterini
Vriza
,
Luke A.
Johnson
,
Bhupendra
Mali
,
Yuri
Tanuma
,
Todd Wesley
Surta
,
John B.
Claridge
,
Neil
Berry
,
Denis
Arčon
,
Matthew S.
Dyer
Open Access
Abstract: We report the synthesis, structural characterization and magnetic properties of K3coronene, and demonstrate a computational screening workflow designed to accelerate the discovery of metal intercalated polycyclic aromatic hydrocarbon (PAH), a class of materials of interest following reports of superconductivity, but lacking demonstrated and understood characterised materials compositions. Coronene is identified as a suitable PAH candidate from a library of PAHs for potassium intercalation by computational screening of their electronic structure and of the void space in their crystal structures, targeting LUMO similarity to C60 and the availability of suitable sites to accommodate inserted cations. Convex hull calculations with energies from crystal structure prediction based on ion insertion into the identified void space of coronene suggest that the x = 3 composition in Kxcoronene is stable at 0 K, reinforcing the suitability of coronone for experimental investigation. Exploration of reaction conditions and compositions revealed that the mild reducing agent KH allows formation of K3coronene. The structure of K3coronene solved from synchrotron powder X-ray diffraction features extensive reorientation and associated disorder of coronene molecules compared with the parent pristine host. This is driven by K+ intercalation and occupation of sites both within and between the coronene stacks that are partially retained from the parent structure. This disruption of the host structure is greater when three cations are inserted per coronene than in reported metal PAH structures where the maximum ratio of cations to PAH is 2. Superconductivity is not observed, contrary to previous reports on Kxcoronene. The expected localised moment response of coronene3- is suppressed, which may be associated with the combination of extensive disorder and close coronene3- - coronene3- contacts.
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Dec 2024
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[29271, 31578]
Open Access
Abstract: The catalytic hydrogenolysis process offers the selective production of high-value liquid alkanes from waste polymers. Herein, through normalisation of Ni structure, Ni mass and density, and CeO2 crystallite size, the importance of CeO2 nanocube morphology in the hydrogenolysis of polypropylene (Mw = 12[thin space (1/6-em)]000 g mol−1; Mn = 5000 g mol−1) over Ni/CeO2 catalysts was determined. High liquid productivities (65.9–70.9 gliquid gNi−1 h−1) and low methane yields (10%) were achieved over two different Ni/CeO2 catalysts after 16 h reaction due to the high activity and internal scission selectivity of the supported ultrafine Ni particles (<1.3 nm). However, the Ni/CeO2 nanocube catalyst exhibited higher C–C scission rates (838.1 mmol gNi−1 h−1) than a standard benchmark mixed shape Ni/CeO2 catalyst (480.3 mmol gNi−1 h−1) and represents a 75% increase in depolymerisation activity. This led to shorter hydrocarbon chains achieved by the nanocube catalyst (Mw = 2786 g mol−1; Mn = 1442 g mol−1) when compared to the mixed shape catalyst (Mw = 4599 g mol−1; Mn = 2530 g mol−1). The enhanced C–C scission rate of the nanocube catalyst was determined to arise from a combination of improved H-storage and favourable basic properties, with higher weak basic site density key to facilitate a greater degree of hydrocarbon chain adsorption.
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Dec 2024
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I19-Small Molecule Single Crystal Diffraction
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Cara J.
Hawkins
,
Jon A.
Newnham
,
Batoul
Almoussawi
,
Nataliya L.
Gulay
,
Samuel L.
Goodwin
,
Marco
Zanella
,
Troy D.
Manning
,
Luke M.
Daniels
,
Matthew S.
Dyer
,
Tim D.
Veal
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[30461]
Open Access
Abstract: Mixed anion halide-chalcogenide materials have recently attracted attention for a variety of applications, owing to their desirable optoelectronic properties. We report the synthesis of a previously unreported mixed-metal chalcohalide material, CuBiSeCl2 (Pnma), accessed through a simple, low-temperature solid-state route. The physical structure is characterized through single-crystal X-ray diffraction and reveals significant Cu displacement within the CuSe2Cl4 octahedra. The electronic structure of CuBiSeCl2 is investigated computationally, which indicates highly anisotropic charge carrier effective masses, and by experimental verification using X-ray photoelectron spectroscopy, which reveals a valence band dominated by Cu orbitals. The band gap is measured to be 1.33(2) eV, a suitable value for solar absorption applications. The electronic and thermal properties, including resistivity, Seebeck coefficient, thermal conductivity, and heat capacity, are also measured, and it is found that CuBiSeCl2 exhibits a low room temperature thermal conductivity of 0.27(4) W K–1 m–1, realized through modifications to the phonon landscape through increased bonding anisotropy.
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Apr 2024
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I11-High Resolution Powder Diffraction
I19-Small Molecule Single Crystal Diffraction
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Guopeng
Han
,
Andrij
Vasylenko
,
Luke M.
Daniels
,
Chris M.
Collins
,
Lucia
Corti
,
Ruiyong
Chen
,
Hongjun
Niu
,
Troy D.
Manning
,
Dmytro
Antypov
,
Matthew S.
Dyer
,
Jungwoo
Lim
,
Marco
Zanella
,
Manel
Sonni
,
Mounib
Bahri
,
Hongil
Jo
,
Yun
Dang
,
Craig M.
Robertson
,
Frédéric
Blanc
,
Laurence J.
Hardwick
,
Nigel D.
Browning
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[30461, 31578]
Abstract: Fast cation transport in solids underpins energy storage. Materials design has focused on structures that can define transport pathways with minimal cation coordination change, restricting attention to a small part of chemical space. Motivated by the greater structural diversity of binary intermetallics than that of the metallic elements, we used two anions to build a pathway for three-dimensional superionic lithium ion conductivity that exploits multiple cation coordination environments. Li7Si2S7I is a pure lithium ion conductor created by an ordering of sulphide and iodide that combines elements of hexagonal and cubic close-packing analogously to the structure of NiZr. The resulting diverse network of lithium positions with distinct geometries and anion coordination chemistries affords low barriers to transport, opening a large structural space for high cation conductivity.
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Feb 2024
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[23666]
Open Access
Abstract: Understanding the structure-property relationships of materials in order to supress thermal conductivity is crucial for developing efficient thermoelectric generators and thermal barrier coatings. We synthesise two mixed-anion materials, Bi8CsO8SeX7 (X = Cl and Br), with low thermal conductivities of 0.27(2) and 0.22(2) W m-1 K-1 respectively, associated with their c-axes at room temperature. These materials possess a combination of bond strength hierarchies and low frequency Cs+ rattling, which significantly inhibits phonon transport along different crystallographic directions. Due to sharp bond strength contrast between the van der Waals gaps and [Bi2O2]2+ layers, Bi8CsO8SeX7 materials exhibit thermal conductivities <50% of the theoretical minimum when measured along the stacking direction. Conversely, the thermal conductivity associated with the ab-plane is reduced by Cs+ rattling when compared to the structurally and compositionally related BiOCl. This highlights how combining different structural features into one material can aid in the design and identification of new materials with low thermal conductivities.
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Jun 2023
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I11-High Resolution Powder Diffraction
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Bernhard T.
Leube
,
Christopher M.
Collins
,
Luke M.
Daniels
,
Benjamin B.
Duff
,
Yun
Dang
,
Ruiyong
Chen
,
Michael W.
Gaultois
,
Troy D.
Manning
,
Frédéric
Blanc
,
Matthew S.
Dyer
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[17193]
Open Access
Abstract: A tetragonal argyrodite with >7 mobile cations, Li7Zn0.5SiS6, is experimentally realized for the first time through solid state synthesis and exploration of the Li–Zn–Si–S phase diagram. The crystal structure of Li7Zn0.5SiS6 was solved ab initio from high-resolution X-ray and neutron powder diffraction data and supported by solid-state NMR. Li7Zn0.5SiS6 adopts a tetragonal I4 structure at room temperature with ordered Li and Zn positions and undergoes a transition above 411.1 K to a higher symmetry disordered F43m structure more typical of Li-containing argyrodites. Simultaneous occupation of four types of Li site (T5, T5a, T2, T4) at high temperature and five types of Li site (T5, T2, T4, T1, and a new trigonal planar T2a position) at room temperature is observed. This combination of sites forms interconnected Li pathways driven by the incorporation of Zn2+ into the Li sublattice and enables a range of possible jump processes. Zn2+ occupies the 48h T5 site in the high-temperature F43m structure, and a unique ordering pattern emerges in which only a subset of these T5 sites are occupied at room temperature in I4 Li7Zn0.5SiS6. The ionic conductivity, examined via AC impedance spectroscopy and VT-NMR, is 1.0(2) × 10–7 S cm–1 at room temperature and 4.3(4) × 10–4 S cm–1 at 503 K. The transition between the ordered I4 and disordered F43m structures is associated with a dramatic decrease in activation energy to 0.34(1) eV above 411 K. The incorporation of a small amount of Zn2+ exercises dramatic control of Li order in Li7Zn0.5SiS6 yielding a previously unseen distribution of Li sites, expanding our understanding of structure–property relationships in argyrodite materials.
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Apr 2022
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I11-High Resolution Powder Diffraction
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Dingyue
Hu
,
Karl
Dawson
,
Marco
Zanella
,
Troy D.
Manning
,
Luke M.
Daniels
,
Nigel D.
Browning
,
B. Layla
Mehdi
,
Yaobin
Xu
,
Houari
Amari
,
J. Felix
Shin
,
Michael J.
Pitcher
,
Ruiyong
Chen
,
Hongjun
Niu
,
Bowen
Liu
,
Matthew
Bilton
,
Junyoung
Kim
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[23666]
Open Access
Abstract: Performance durability is one of the essential requirements for solid oxide fuel cell materials operating in the intermediate temperature range (500–700 °C). The trade-off between desirable catalytic activity and long-term stability challenges the development and commercialization of electrode materials. Here an oxygen cathode material, Ba0.5Sr0.5(Co0.7Fe0.3)0.69−xMgxW0.31O3−δ (BSCFW-xMg), that exhibits excellent electrocatalytic performance through the addition of an optimized amount of Mg to the self-assembled nanocomposite Ba0.5Sr0.5(Co0.7Fe0.3)0.69W0.31O3−δ (BSCFW) by simple solid-state reaction is reported. Distinct from the bulk and surface approaches to introduce vacancies and defects in materials design, here the Mg2+ ions concentrate at the single perovskite/double perovskite interface of BSCFW with dislocations and Mg2+-rich nanolayers, resulting in stressed and compositionally inhomogeneous interface regions. The interfacial chemistry within these nanocomposites provides an additional degree of freedom to enable performance optimization over single phase materials and promotes the durability of alkaline-earth based fuel cell materials.
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Mar 2022
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I11-High Resolution Powder Diffraction
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Open Access
Abstract: Protonic ceramic fuel cells (PCFCs) are attractive energy conversion devices for intermediate-temperature operation (400-600 °C), however widespread application of PCFCs relies on the development of new high-performance electrode materials. Here we report the electrochemical and protonic properties of a self-assembled nanocomposite, Ba0.5Sr0.5(Co0.7Fe0.3)0.6875W0.3125O3−δ (BSCFW) consisting of a disordered single perovskite and an ordered double perovskite phase, as a PCFC cathode material. BSCFW shows thermodynamic and kinetic protonic behaviour conducive to PCFC application with favourable proton defect formation enthalpy (ΔH = -35±7 kJ mol–1) comparable to existing proton conducting electrolyte materials. BSCFW presents an excellent polarization resistance (Rp) of 0.172(2) Ω cm2 at 600 °C and a high power density of 582(1) mW cm–2 through singlecell measurement, which is comparable performance to current state-of-the-art cathode materials. BSCFW exhibits good chemical and thermal stability against BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) electrolyte with a low Rp degradation rate of 1.0(1) × 10-6 Ω cm2 min-1. These performance and stability figures represent an advance beyond those of Ba0.5Sr0.5Co0.7Fe0.3O3−δ (BSCF), which is unstable under the same conditions and is incompatible with the electrolyte material. Our comprehensive characterization of the protonic properties of BSCFW, whose performance and stability are ensured via the interplay of the single and double perovskite phases, provides fundamental understanding that will inform the future design of high-performance PCFC cathodes.
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Dec 2021
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