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Instruments / Technical Area	Publication Details	Published
I22-Small angle scattering & Diffraction	Aged layered double hydroxide nanosheet–polyvinyl alcohol dispersions for enhanced gas barrier coating performance Jingfang Yu , Chunping Chen , James B. Gilchrist , Jean-Charles Buffet , Zhonghua Wu , Guang Mo , Fei Xie , Dermot O'Hare Materials Horizons 335 DOI: 10.1039/D1MH00433F Diamond Proposal Number(s): [17095] Open Access Show Abstract ▼ Abstract: Whilst applying a coating layer to a polymer film is a routine approach to enhance the gas barrier properties of the film, it is counter-intuitive to consider that the gas barrier performance of the film would improve by ageing the coating dispersion for weeks before application. Herein, we report that the oxygen barrier performance of a 12 μm PET film coated with a dispersion of inorganic nanosheets in polyvinyl alcohol can be significantly enhanced by ageing this coating dispersion for up to 8 weeks before application. We found up to a 37-fold decrease in the oxygen transmission rate (OTR) of the PET coated film using aged dispersions of [Mg0.66Al0.33(OH)2](NO3)0.33 layered double hydroxide nanosheets (Mg2Al-LDH NS) in polyvinyl alcohol (PVA) compared to the film coated with an equivalent freshly prepared LDH/PVA dispersion. A limiting OTR value of 0.31 cc m−2 day−1 was achieved using the PET film coated with a 3 week aged LDH NS/PVA dispersion. X-ray diffraction experiments show that the degree of in plane alignment of LDH NS on the PET film surface increased significantly from 70.6 ± 0.6 to 86.7 ± 0.6 (%) (100% represents complete alignment of LDH NS platelets on the film surface) for the 4 week aged dispersion compared to the freshly prepared layer. We postulate that when the Mg2Al-LDH NS are aged in PVA the coiled PVA aggregates start to unwrap and attach onto the Mg2Al-LDH NS through hydrogen bonding and eventually form a hydrogen bonded ordered network that facilitates the alignment of nanosheet dispersions during the coating process. Our results suggest that the ageing of inorganic nanosheet dispersions in PVA or other potential hydrogen bonding adhesive systems could be a general approach to improve the alignment of the nanosheets on the polymer film surface once applied and thus improve their performance characteristics for barrier coating applications.	Sep 2021
I15-1-X-ray Pair Distribution Function (XPDF)	Polymethylaluminoxane organic frameworks (sMAOF) – highly active supports for slurry phase ethylene polymerisation Alexander F. R. Kilpatrick , Harry S. Geddes , Zoe R. Turner , Jean-Charles Buffet , Andrew L. Goodwin , Dermot O'Hare Catalysis Science & Technology 15 DOI: 10.1039/D1CY00767J Diamond Proposal Number(s): [16072, 19128] Open Access Show Abstract ▼ Abstract: A series of modified solid polymethylaluminoxane (sMAO) catalyst supports have been developed for slurry phase ethylene polymerisation, using aryl di-ol modifier groups. Characterisation using ICP-MS analysis, X-ray total scattering, SEM–EDX, diffuse FT-IR and solid state NMR spectroscopy shows that the organic linker groups are uniformly distributed in a proposed organic framework stucture we call a “sMAOF”. When used as a support for rac-ethylene{bis(1-indenyl)} zirconium dichloride, (EBI)ZrCl2, these linker modified sMAOF materials provide a 40% enhancement in polymerisation activity with respect to unmodified sMAO: activities of 163 × 103 and 116 × 103 kgPE molZr−1 h−1 at 80 °C for (EBI)ZrCl2 supported on sMAOF(1,4-HO(C6F4)OH) and sMAO, respectively. The observed activity increase is correlated with the higher BET surface area and increased porosity in the linker modified sMAOF activating support.	Jul 2021
E01-JEM ARM 200CF	Molecular nitrogen promotes catalytic hydrodeoxygenation Haohong Duan , Jin-Cheng Liu , Ming Xu , Yufei Zhao , Xue-Lu Ma , Juncai Dong , Xusheng Zheng , Jianwei Zheng , Christopher Allen , Mohsen Danaie , Yung-Kang Peng , Titipong Issariyakul , Dongliang Chen , Angus Kirkland , Jean-Charles Buffet , Jun Li , Shik Chi Edman Tsang , Dermot O'Hare Nature Catalysis 345 DOI: 10.1038/s41929-019-0368-6 Diamond Proposal Number(s): [16969, 17397] Show Abstract ▼ Abstract: Although molecular dinitrogen (N2) is widely used as a carrier or inert gas for many catalytic reactions, it is rarely considered as a catalytic promoter. Here, we report that N2 could be used to reduce the activation energy for catalytic hydrodeoxygenation over ruthenium-based catalysts. Specifically, we report a 4.3-fold activity increase in the catalytic hydrodeoxygenation of p-cresol to toluene over a titanium oxide supported ruthenium catalyst (Ru/TiO2) by simply introducing 6 bar N2 under batch conditions at 160 °C and 1 bar hydrogen. Detailed investigations indicate that N2 can be adsorbed and activated on the metallic ruthenium surface to form hydrogenated nitrogen species, which offer protic hydrogen to lower the activation energy of direct carbonaromatic–oxygen bond scission and the hydrogenation of hydroxy groups. Thus, by employing different ruthenium catalysts, including Ru/TiO2, Ru/Al2O3, Ru/ZrO2 and Ru/C, we demonstrate that N2 promotion of hydrodeoxygenation can be regarded as a general strategy.	Oct 2019
B18-Core EXAFS	Zirconium arene triple-decker sandwich complexes: Synthesis, electronic structure and bonding Alexander F. R. Kilpatrick , Jennifer Green , Zoe Turner , Jean-charles Buffet , Dermot O'hare Chem. Commun. DOI: 10.1039/C7CC07083G Diamond Proposal Number(s): [15150, 15521] Show Abstract ▼ Abstract: Reduction of a permethylpentalene zirconium(IV) chloride complex [η8-PnZr(μ-Cl)3/2]2(μ-Cl)2Li·THFx with KC8 in benzene results in activation of the aromatic solvent to yield an “inverted sandwich” complex, [η8-PnZr]2(μ-η6:η6-C6H6) (1). The analogous reactions in toluene, cumene, o-xylene and m-xylene also yield analogous solvent activated triple-decker sandwich complexes, which have been structurally characterised by single-crystal X-ray diffraction. Edge energies in the Zr K-edge XANES spectra are not distinguishable between 1 and formally Zr(II) and Zr(IV) reference compounds, suggesting a broad edge structure. DFT calculations best describe the bonding in 1 as highly covalent with frontier molecular orbitals showing almost equal contributions from benzene and the Zr-permethylpentalene fragments.	Oct 2017
B18-Core EXAFS	Highly tuneable catalyst supports for single-site ethylene polymerization Jean Charles Buffet , Nidwaree Wanna , Thomas A Q Arnold , Emma Gibson , Peter Wells , Qiang Wang , Jonggol Tantirungrotechai , Dermot O'hare Chemistry of Materials DOI: 10.1021/cm503433q Diamond Proposal Number(s): [8071] Open Access Show Abstract ▼ Abstract: A new class of tuneable crystalline solid supports for metal complexes have been synthesised and used for ethylene polymerization. We have developed a family of high surface area, highly dispersible layered double hydroxides (AMO-LDHs) which, on treatment with alkyl aluminum activators, are able to support metallocene and non-metallocene complexes to make active catalyst systems for the slurry polymerization of ethylene. We show that the chemical composition of the AMO-LDH support can dramatically affect catalyst activity, polymer morphology, and polymer microstructure. A Zr K-edge EXAFS study of these active catalysts has enabled us to observe a metallocene-derived single-center catalytic species in close proximity to the support.	Feb 2015

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