Tuning the plasmonic response of TiN nanoparticles synthesised by the transferred arc plasma technique.

Titanium nitride exhibits plasmonic behaviour in the visible and NIR region. Combined with a refractory nature, it can be an attractive alternate plasmonic material useful in many applications. Despite the plethora of methods to produce TiN nanoparticles, it remains challenging to generate high quality TiN nanoparticles efficiently. Here we demonstrate the transferred arc plasma technique as a viable way to synthesise TiN nanoparticles. We show here that modulating the processing conditions can control the optical properties and tune the plasmonic response rendering the application of TiN nanoparticles viable across many applications.

Opportunities in upgrading biomass crudes.

An unconventional crude from biomass (biocrude) has been processed to yield a hydrocarbon stream that is not only fully processable in conventional refineries but is already close to the specification of commercial fuels such as transportation diesel. The upgrading of biocrude was carried out with a combination of hydrotreatment and catalytic cracking, yielding middle distillate as the main product.

Biocrude yield and productivity from the hydrothermal liquefaction of marine and freshwater green macroalgae.

Six species of marine and freshwater green macroalgae were cultivated in outdoor tanks and subsequently converted to biocrude through hydrothermal liquefaction (HTL) in a batch reactor. The influence of the biochemical composition of biomass on biocrude yield and composition was assessed. The freshwater macroalgae Oedogonium afforded the highest biocrude yield of all six species at 26.2%, dry weight (dw). Derbesia (19.7%dw) produced the highest biocrude yield for the marine species followed by Ulva (18.7%dw). In contrast to significantly different yields across species, the biocrudes elemental profiles were remarkably similar with higher heating values of 33-34MJkg(-1). Biocrude productivity was highest for marine Derbesia (2.4gm(-2)d(-1)) and Ulva (2.1gm(-2)d(-1)), and for freshwater Oedogonium (1.3gm(-2)d(-1)). These species were therefore identified as suitable feedstocks for scale-up and further HTL studies based on biocrude productivity, as a function of biomass productivity and the yield of biomass conversion to biocrude.

One-step synthesis of a highly active, mesoporous, titanium-containing silica by using bifunctional templating.

A highly active, three-dimensional, mesoporous titanosilica, TiTUD-1, with comparable properties to Ti-grafted mesoporous silica MCM-41, has been prepared in a one-step synthesis. A non-surfactant chemical, triethanolamine, was used as a template molecule. Triethanolamine easily forms complexes with titanium alkoxides, yielding titanatrane complexes, which together with free triethanolamine form meso-sized aggregates that template mesopores upon increasing the temperature of the synthesis mixture. Triethanolamine served as both mesopore template and ligand for the titanium complexes, which represent the majority of the catalytic-site precursors. The formation of the silica network and the titanium insertion were followed by a combination of diffuse reflectance UV/ Vis/NIR and FTIR spectroscopy. A titanium-rich phase was obtained on the mesopore surfaces during calcination, allowing for easy accessibility of the reactants to the catalytic sites. TiTUD-1 is about six times more active than framework-substituted Ti-MCM-41 and has similar activity to Ti-grafted MCM-41.

Zirconium(IV) complexes of oxydiacetic acid in aqueous solution and in the solid state as studied by multinuclear NMR and X-ray crystallography.

The structures of complexes of Zr(IV) and oxydiacetate (ODA2-) in aqueous solutions of pH 0-7 were investigated with the use of 1H, 13C, and 17O NMR spectroscopy. Equilibria of mononuclear [Zr(oda)]2+, [Zr(oda)2], and [Zr(oda)3]2- complexes have been observed. In all complexes ODA2- is bound in a tridentate fashion through the two carboxylate groups and the ether oxygen. No di- or oligonuclear species containing ODA2- were observed. An excess of free Zr(IV) remains in solution, probably as a result of weak electrostatic interactions between negatively charged Zr-ODA complexes or free ODA2- and a positively charged cyclic tetranuclear hydroxy zirconium complex. CP-MAS 13C NMR spectra of solid compounds isolated from the samples indicated that the structures of the [Zr(oda)2] and [Zr(oda)3]2- complexes in solution are similar to those in the solid state. This is corroborated by the single-crystal X-ray structure of Na2[Zr(oda)3] x 5.5 H2O, which was obtained from a solution containing exclusively the [Zr(oda)3]2- complex. In this structure Zr(IV) is nine-coordinate with the three ODA2- ligands bound in a tricapped trigonal prismatic geometry. The negative charge of this [Zr(oda)3]2complex is balanced by two Na+ ions, one of which is on a center of symmetry between delta and lambda enantiomers of [Zr(oda)3]2-. This Na+ is octahedrally coordinated to six (non Zr(IV)-bound) carboxylate oxygen atoms of six different [Zr(oda)3]2- units.

Controlling the performance of silicalite-1 membranes

The structural and performance characteristics (for n- and i-butane separation) of self-supported silicalite-membranes, were optimised by fine-tuning their syntheses by screening a total of nine silica sources and many reaction conditions. The mass balances indicate that membrane thickness is a function of both the synthesis volume and the silica source used. The excellent properties of the final membrane are demonstrated by its high permselectivity of 31 for n-butane combined with a n-butane flux of 10 mmol m(-2)s(-1), indicating perfect performance. For 50/50 mixtures (of n and i) the selectivity for nbutane was 48 and its flux was 3.8 mmol m(-2)s(-1). For the given selectivities, in relation to the membrane thickness, the theoretical fluxes are the highest values ever reported, underlining the point that high structural integrity is essential to achieve superior functionality.

Ordering of ruthenium cluster carbonyls in mesoporous silica

The anionic ruthenium cluster carbonylates [Ru6C(CO)16]2- or [H2Ru10(CO)25]2- interspersed with bis(triphenylphosphino)iminium counterions (PPN+) are incorporated from solution into the pores of MCM-41 mesoporous silica (3 nanometers in diameter), where they form tightly packed arrays. These arrays were shown by high-resolution transmission electron microscopy, Fourier transform optical diffraction, and computer simulations to be well ordered both along and perpendicular to the axis of the cylindrical pores. In their denuded state produced by gentle thermolysis, the cluster carbonylates yield nanoparticles of ruthenium that are less well ordered than their assimilated precursors but show good activity as hydrogenation catalysts for hexene and cyclooctene. In both their as-prepared and denuded states, these encapsulated clusters are likely to exhibit interesting electronic and other properties.