Browsing by Author "Ogilvie, SH"

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    Continuous negative-to-positive tuning of thermal expansion achieved by controlled gas sorption in porous coordination frameworks
    (Springer Nature, 2018-11-19) Auckett, JE; Barkhordarian, AA; Ogilvie, SH; Duyker, SG; Chevreau, H; Peterson, VK; Kepert, CJ
    Control of the thermomechanical properties of functional materials is of great fundamental and technological significance, with the achievement of zero or negative thermal expansion behavior being a key goal for various applications. A dynamic, reversible mode of control is demonstrated for the first time in two Prussian blue derivative frameworks whose coefficients of thermal expansion are tuned continuously from negative to positive values by varying the concentration of adsorbed CO2. A simple empirical model that captures site-specific guest contributions to the framework expansion is derived, and displays excellent agreement with the observed lattice behaviour. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License.
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    Coordination frameworks: host-guest chemistry and structural dynamics
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2012-11-07) Ogilvie, SH; Duyker, SG; Peterson, VK; Kepert, CJ
    Coordination frameworks employ metal ions possessing well defined coordination geometries and an extensive range of molecular bridging ligands with a vast array of functional groups to produce microporous materials with a range of interesting and useful properties. My PhD research is focused towards characterising the structural behaviour of three of these properties in metal-cyanide and metal-imidazolate materials: 1) gas adsorption; 2) metal insertion and; 3) anomalous thermal expansion. Neutron diffraction and scattering are central to all three areas and provide essential information that cannot be readily obtained from other techniques. This is largely due to their sensitivity to light atoms, important for determining the location of light atoms (e.g. CO2 and Li+ ions); their highly penetrating nature, allowing the use of highly specialised sample environments; and their inelastic scattering to provide information on host-guest binding energetics. Gas Adsorption: The primary goal is to elucidate the packing and ordering behaviours of carbon dioxide. These frameworks contain a variety of functional groups which have a known affinity for interaction with CO2, making them suitable for the selective separation of gas mixtures commonly found as flue gas streams of combustion power sources. Metal insertion: The goal is to develop structural understandings of the redox-insertion of lithium and sodium into metal-cyanide phases for the development of new battery electrode materials. Recent work from our group has shown very high reversible loadings of Li into these materials, with in-situ NPD at OPAL used to determine the structures during insertion. Anomalous thermal expansion: Our group has previously investigated the anomalous thermal expansion behaviour in a range of coordination frameworks. Using both NPD and INS, the goal of this project is to develop an even greater understanding of guest influence on these temperature dependent structural behaviours.
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    Host–guest adsorption behavior of deuterated methane and molecular oxygen in a porous rare-earth metal–organic framework
    (Cambridge Core, 2014-11-17) Ogilvie, SH; Duyker, SG; Southon, PD; Peterson, VK; Kepert, CJ
    The yttrium-based metal–organic framework, Y(btc) (btc = 1,3,5-benzenetricarboxylate), shows moderate uptake of methane (0.623 mmol g−1) and molecular oxygen (0.183 mmol g−1) at 1 bar and 308 K. Neutron powder-diffraction data for the guest-free, CD4-, and O2-loaded framework reveal multiple adsorption sites for each gas. Both molecular guests exhibit interactions with the host framework characterised by distances between the framework and guest atoms that range from 2.83 to 4.81 Å, with these distances identifying interaction most commonly between the guest molecule and the carboxylate functional groups of the benzenetricarboxylate bridging ligand of the host. © 2014, International Centre for Diffraction Data.
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    Identification of bridged CO2 binding in a Prussian blue analogue using neutron powder diffraction
    (Royal Society of Chemistry, 2013-01-01) Ogilvie, SH; Duyker, SG; Southon, PD; Peterson, VK; Kepert, CJ
    Neutron powder diffraction measurements were carried out on the evacuated and CO2-loaded Prussian blue analogue, Fe3[Co(CN)6]2, identifying two distinct CO2 adsorption sites: site A, in which CO2 uniquely bridges between two bare-metal sites, and site B, in which it interacts in a face capping motif. The saturation of site A at low loadings of CO2 demonstrates the favourable nature of the interaction of CO2 with bare-metal sites within the material. © 2013, Royal Society of Chemistry.
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    Neutron diffraction and in situ gas-loading investigations of functional MOFs for energy-relevant gas separations
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2012-11-08) Duyker, SG; Peterson, VK; Ogilvie, SH; Turner, DR; Hill, MR; D'Alessandro, DM; Kepert, CJ
    Intense research is currently directed towards realising metal-organic frameworks (MOFs) for industrially-applied gas separation and storage due to their unique structural properties, including: robustness; thermal and chemical stability; unprecedented internal surface area; and high void volume. A particular focus of current research is the development of MOFs for the separation of CO, from the other components of flue gas in fossil-fuelled power plants. The use of NPD to study gas adsorption in framework materials is a relatively new but growing field. Structural measurements, which show the arrangement of both the host and guest, allow derivation of the nature of the host-guest interaction, and the host's response to the guest. The capability to perform these measurements, with accurate gas dosing and temperature control, has recently been realised at ANSTO's Bragg Institute. Using these techniques, we have investigated the adsorption mechanisms of a number of gases in selected new and established MOFs that display impressive selectivity for specific gases. The location and orientation of industrially-relevant gases including D2, 02, CO2, and CD4, within their crystal structures provide insights into the modes of binding, which will help to tune the materials' performance and benefit the design and development process for the next generation of materials.