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Abstract: The heterogeneously catalyzed oxidation of bioethanol offers a promising route to bio-based acetic acid. Here, we assess an alternative method to support gold nanoparticles, which aims to improve selectivity to acetic acid through minimizing over-oxidation to carbon dioxide. The most promising support system is 5 wt % titanium on silica, which combines the high surface area of silica with the stabilizing effect of titania on the gold particles. Compared to gold–silica systems, which require a complex synthesis method, small quantities of titanium promoted the formation of gold nanoparticles during a simple deposition–precipitation. Characterization of the catalyst with X-ray absorption spectroscopy shows that titanium is highly dispersed in the form of small, possibly dimeric, titanium(IV) structures, which are isolated and stabilize gold nanoparticles, possibly minimizing sintering effects during synthesis. The size of the gold particles depends on the pre-treatment of the titanium–silica support before gold deposition, with larger titanium structures hosting larger gold particles. Acetic acid yield over the titanium–silica-supported gold systems improved by about 1.6 times, compared to pure titania-supported gold. The high activity of those catalysts suggests that bulk, crystalline titania is not required for the reaction, encouraging the use of mixed supports to combine their benefits. Those support systems, besides improving selectivity, offer high surface area and a low-cost filler material, which brings ethanol oxidation one step further to the industry. Additionally, the low loading of titanium permits studying the reaction mechanisms on the gold–titanium interface with bulk characterization techniques.

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Abstract: Amorphous and polycrystalline Sn‐doped IrO2 thin films, Ir1‐xSnxO2, are grown for the first time. Their electrical response and strength of the spin–orbit coupling are studied in order to better understand and tailor its performance as spin current detector material. These experiments prove that the resistivity of IrO2 can be tuned over several orders of magnitude by controlling the doping content in both the amorphous and the polycrystalline state. In addition, growing amorphous samples increase the resistivity, thus improving the spin current to charge current conversion. As far as the spin–orbit coupling is concerned, the system not only remains in a strong spin–orbit coupling regime but it seems to undergo a slight enhancement in the amorphous state as well as in the Sn‐doped samples.

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Abstract: This research intends to explore strategies able to modify the activity of heterogeneous catalysts, in order to draw structure-activity relationships and gain an improved understanding of the catalytically active sites. Different approaches have been attempted, such as applying an activation treatment, modifying the metal loading, changing the support and adding organic ligands. These methods have been applied to supported noble metal nanoparticles of Pt, Pd and bimetallic AuPd, which have been previously found active for liquid-phase hydrogenation and oxidation reactions such as the reduction of nitro compounds and the oxidation of alcohols. Several characterisation methods were applied to study the structure and properties of these materials. First, a Pt/TiO2 catalyst for the selective hydrogenation of 3-nitrostyrene has been developed by optimising the effect of the variation of metal loading and heat treatment. In particular, a series of catalysts were prepared, tested and characterised, showing that combining the choice of metal loading (from 0.05 to 0.5%Pt) and activation treatment (reduction or calcination followed by reduction at 450 °C) leads to what shows to be the most active catalyst reported so far. The data acquired by several characterisation techniques such as STEM, XPS, XAS and CO adsorption led to the conclusion that particle size and distribution as well as the environment surrounding the active site affect the catalytic activity and a delicate balance between them needs to be achieved. Then, the role of the support on the catalytic activity of AuPd nanoparticles for the oxidation of glycerol was investigated. Different hydrothermal carbon materials, which derive from biomass and presenting different structural and elemental characteristics were applied as supports. Overall, the amount of oxygen in the structure as well as the curvature of the surface of the hydrothermal carbons showed to have an effect on the glycerol conversion either due to the variation in electron mobility that would favour adsorption of the reactants, or to the strain arising from the lattice mismatch at the metal-support interface. At last, N-heterocyclic carbene ligands were added to a 1% Pd/TiO2 catalyst. The presence of the ligand on the surface of the catalyst has been confirmed and found to be in both a neutral and protonated form. The results obtained by testing these catalysts for the hydrogenation of 3- nitrostyrene and the direct synthesis of hydrogen peroxide suggest that catalytic performance can be affected by either a geometric effect, where active sites are blocked, or by an electronic effect, due to the electronic interaction of the ligands and the Pd nanoparticles. Overall, to develop catalytic materials and improve industrial processes, the reactivity of nanoparticles needs to be maximised, by using strategies that tune their structural and electronic properties.

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Abstract: CoCrMo-based metal-on-metal hip implants experienced unexpectedly high failure rates despite the high wear and corrosion resistance of the bulk material. Although they exhibit a lower volumetric wear compared to other implant materials, CoCrMo-based implants produced a significantly larger 'number' of smaller wear particles. CoCrMo is nominally an extremely stable material with high Cr content providing passivity. However, despite the Co:Cr ratio in the original alloy being 2:1; chemical analyses of wear particles from periprosthetic tissue have found the particles to be composed predominately of Cr species, with only trace amounts of Co remaining. Here a correlative spectroscopy and microscopy approach has shown that these particles dissolve via a non-stoichiometric, and geometrically inhomogeneous, mechanism similar to de-alloying. This mechanism is previously unreported for this material and was not apparent in any of the regulatory required tests, suggesting that such tests are insufficiently discriminating.

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Abstract: The microscopic structure of solutions and the interactions of their constituent chemical species are topics of long standing interest and importance in the chemical sciences. Like many fields of condensed matter research, techniques developed at large scale facilities such as X-ray synchrotrons and pulsed or reactor based neutron sources have, over the past few decades, played a significant role in unravelling many of the mysteries that underpin the chemical, physical and biochemical properties of these systems. In this article we set out to review a subset of these methods, specifically X-ray diffraction, neutron diffraction and X-ray absorption spectroscopy, as well as their combined application to the investigation of structural questions on aqueous electrolyte solutions. Particular emphasis will be given to the use of analytical approaches based on atomistic computer modelling of the experimental data.