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We have used liquid-feed Flame Spray Pyrolysis (FSP) to prepare a series of high surface area, nanocrystalline perovskites of general formula AA’BB’O3 (A = La, A’ = Ca, Sr, Y, Ce; B = B’ = Mn, Fe, Co, Ni). Use of the FSP method has allowed the systematic investigation of changing both A site dopant and B site cation while maintaining high surface areas. The resulting perovskites have been evaluated for their CO, HC and NO (three-way catalyst (TWC)) activity under simulated gasoline exhaust feeds, their oxygen storage properties and their stability to high temperature redox conditions. The activity of the perovskites has been compared to a low loaded commercial PdRh TWC and were found to be significantly poorer after mild calcination and very significantly deactivated after high temperature hydrothermal redox ageing.

Rachel A Morrison,1,* Malgorzata J Rybak-Smith,1,* James M Thompson,2 Bénédicte Thiebaut,3 Mark A Hill,2 Helen E Townley1,4 1Department of Engineering Science, 2Gray Laboratories, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, 3Johnson Matthey, Technology Centre, Reading, Berkshire, 4Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, University of Oxford, Oxford, UK *These authors have contributed equally to this work Abstract: The aim of this study was to develop a manufacturing protocol for large-scale production of doped titania radiosensitizing nanoparticles (NPs) to establish their activity under hypoxia and to produce a multimodal radiosensitizing embolic particle for cancer treatment. We have previously shown that radiosensitizing NPs can be synthesized from titania doped with rare earth elements, especially gadolinium. To translate this technology to the clinic, a crucial step is to find a suitable, scalable, high-throughput method. Herein, we have described the use of flame spray pyrolysis (FSP) to generate NPs from titanium and gadolinium precursors to produce titania NPs doped with 5at% gadolinium. The NPs were fully characterized, and their capacity to act as radiosensitizers was confirmed by clonogenic assays. The integrity of the NPs in vitro was also ascertained due to the potentially adverse effects of free gadolinium in the body. The activity of the NPs was then studied under hypoxia since this is often a barrier to effective radiotherapy. In vitro radiosensitization experiments were performed with both the hypoxia mimetics deferoxamine and cobalt chloride and also under true hypoxia (oxygen concentration of 0.2%). It was shown that the radiosensitizing NPs were able to cause a significant increase in cell death even after irradiation under hypoxic conditions such as those found in tumors. Subsequently, the synthesized NPs were used to modify polystyrene embolization microparticles. The NPs were sintered to the surface of the microparticles by heating at 230°C for 15minutes. This resulted in a good coverage of the surface and to generate embolization particles that were shown to be radiosensitizing. Such multimodal particles could therefore result in occlusion of the tumor blood vessels in conjunction with localized reactive oxygen species generation, even under hypoxic conditions such as those found in the center of tumors. Keywords: cancer, ROS, reactive oxygen species, titania, multimodal

With the rapid advancement of nanotechnology and with nanoparticles beginning to enter into products, the demand for production-level quantities of advanced nanopowders such as multi-component or coated oxides is rising. Such advanced nanoparticles can be effectively made by flame spray pyrolysis (FSP), and research with laboratory reactors yielded a spectrum of new nanomaterials for catalysis, pigments, ceramics, optics, energy and biomaterials, among others. Here, the transfer of FSP nanopowder synthesis from gram-level lab-scale to pilot reactors with up to 10 metric tons annual production rate is investigated by the example of FSP pilot plants that were realized in industrial-oriented settings. Design considerations for such pilot-scale systems are addressed and guides to production cost estimates are given. Special attention is brought to safe and contained nanoparticle manufacture in order to address the growing awareness of the potential health and environmental effects of nanoparticles.

Bimetallic heterostructures are used as industrial catalysts for many important transformations. However, conventional catalysts are primarily prepared in cost-effective manners without much appreciation in metal size control and metal-metal interaction. By employing recent nanotechnology, Pt nanocrystals with tailored sizes can be decorated with Co atoms in a controlled manner in colloid solution as preformed nanocatalysts before they are applied on support materials. Thus, we show that the terminal C=0 hydrogenation can be achieved in high activity, while the undesirable hydrogenation of the C=C group can be totally suppressed in the selective hydrogenation of α,β- unsaturated aldehydes to unsaturated alcohols, when Co decorated Pt nanocrystals within a critical size range are used. This is achieved through blockage of unselective low coordination sites and the optimization in electronic influence of the Pt nanoparticle of appropriate size by the Co decoration. This work clearly demonstrates the advantage in engineering preformed nanoparticles via a bottom-up construction and illustrates that this route of catalyst design may lead to improved catalytic processes. © 2008 American Chemical Society.

A series of crystalline homometallic and heterometallic cobalt and nickel hydroxides and oxides were prepared using a continuous hydrothermal flow synthesis system. In all syntheses, the relevant m...

Reactions of [WI2(CO)3(NCMe)2] with norbornadiene (NBD) and 1,5-cycloctadiene (COD) give six-coordinate dicarbonyls [WI2(CO)2(NBD)] and [WI2(CO)2(COD)], respectively. The related dibromo complex [WBr2(CO)2(NBD)] reacts with tertiary phosphines L to give unstable seven-coordinate adducts [WBr2(CO)2(L)(NBD)] (L=PPh3, PMePh2, PEt3), which in the case of L=PMePh2 was shown to undergo CO loss to give the six-coordinate derivative [WBr2(CO)(PMePh2)(NBD)]. X-ray diffraction studies of [WBr2(CO)2(PMePh2)(NBD)] reveal a seven-coordinate structure (distorted pentagonal bipyramid) with the diene CC bonds on the pentagonal plane lying approximately parallel to the WCO axes. Reactions of [WBr2(CO)2(NBD)] with organonitriles NCR at room temperature afford CO substitution products (R=Me, Pri, Ph, C6H4Me-4, CHCH2) directly with no evidence for seven-coordinate intermediates. [WBr2(CO)2(COD)] and acetonitrile similarly give [WBr2(CO)(NCMe)(COD)]. X-ray diffraction studies of [WBr2(CO)(NCCHCH2)(NBD)] confirmed a distorted octahedral structure where the carbonyl lies trans to the acrylonitrile ligand.

The new phases, Li 1.8K 0.9M 0.75Zr2.25O6.6(M = Cu, Mg), have a novel rocksalt-perovskite intergrowth structure, with space group I4/mmm; a=; 4.1630(1), c= 18.1086(7)A, Z = 2 for M = Cu and a= 4.1739(3), c= 17.971(2)A for M = Mg, formed from ‘KZrO3’ perovskite units and rocksalt units ‘Li2M0.75Zr1.25O3.75’. A weak incommensurate supercell, not detected by X-ray diffraction, was characterised by electron diffraction; the supercell is parallel to [301] of the tetragonal subcell.

Zinc oxide (ZnO) nanoparticles and nanoparticles of luminescent zinc oxide (ZnO:Zn) phosphor were successfully synthesised and well characterised. A transparent polystyrene composite sheet containing ZnO:Zn nanoparticles was prepared by a solvent casting method. The sheet manifested comparable transmission to a virgin polystyrene film due to very uniform dispersion of the ZnO:Zn nanoparticles into the polystyrene. Evidence for uniform dispersion was evident in both its luminescent properties and in a SEM image. The photoluminescent characteristics of the ZnO:Zn, both as a pure powder and embedded in a polystyrene matrix, are reported. The uniformity of the photoluminescence of the composite sheet under near ultraviolet excitation is demonstrated. The luminescent ZnO:Zn nanoparticles are shown to have applications for use not only as an inhibitor of the ultraviolet degradation of polymers, but also for providing polymers with light emitting functionality.