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Solid state reactions are notoriously slow, because the rate‐limiting step is diffusion of atoms or ions through reactant, intermediate, and product crystalline phases. This requires days or even weeks of high temperature treatment, consuming large amounts of energy. Metal oxides are particularly difficult to react, because they have high melting points. The study reports a high‐speed solid state fluorination of WO3 with Teflon to the oxyfluorides WO3-x Fx on a minute (

Multicomponent nanostructures containing purely organic or inorganic as well as hybrid organic-inorganic components connected through a solid interface are, unlike conventional spherical particles, able to combine different or even incompatible properties within a single entity. They are multifunctional and resemble molecular amphiphiles, like surfactants or block copolymers, which makes them attractive for the self-assembly of complex structures, drug delivery, bioimaging, or catalysis. We have synthesized Pd@FexO heterodimer nanoparticles (NPs) to fabricate a macroporous, hydrophobic, magnetically active, three-dimensional (3D), and template-free hybrid foam capable of repeatedly separating oil contaminants from water. The Pd domains in the Pd@FexO heterodimers act as nanocatalysts for the hydrosilylation of polyhydrosiloxane and tetravinylsilane, while the FexO component confers magnetic properties to the final functional material. Pd@FexO heterodimers were synthesized by heterogeneous nucleation and growth of the iron oxide domain onto presynthesized Pd NPs at high temperatures in solution. The morphology, structure, and magnetic properties of the as-synthesized heterodimers were characterized by transmission electron microscopy (TEM), X-ray diffraction, Mössbauer spectroscopy, and a superconducting quantum interference device. The epitaxial growth of the FexO domain onto Pd was confirmed by high-resolution TEM. A potential application of the 3D hydrophobic magnetic foam was exploited by demonstrating its ability to soak oil beneath a water layer, envisioning its use in oil sampling during oil prospection drilling, or to remove oil films after oil spills.

Controlling the morphology of noble-metal nanoparticles is mandatory to tune specific properties such as catalytic and optical behavior. Heterodimers consisting of two noble metals have been synthesized, so far mostly in aqueous media using selective surfactants or chemical etching strategies. We report a facile synthesis for Au@Pd and Pd@Au heterodimer nanoparticles (NPs) with morphologies ranging from segregated domains (heteroparticles) to core-shell structures by applying a seed-mediated growth process with Au and Pd seed nanoparticles in 1-octadecene (ODE), which is a high-boiling organic solvent. The as-synthesized oleylamine (OAm) functionalized Au NPs led to the formation of OAm-Au@Pd heteroparticles with a ""windmill"" morphology, having an Au core and Pd ""blades"". The multiply twinned structure of the Au seed particles (⌀ ≈ 9-11 nm) is associated with a reduced barrier for heterogeneous nucleation. This leads to island growth of bimetallic Au@Pd heteroparticles with less-regular morphologies. The reaction process can be controlled by tuning the surface chemistry with organic ligands. Functionalization of Au NPs (Ø ≈ 9-11 nm) with 1-octadecanethiol (ODT) led to the formation of ODT-Au@Pd NPs with a closed Pd shell through a strong ligand-metal binding, which is accompanied by a redistribution of the electron density. Experiments with varied Pd content revealed surface epitaxial growth of Pd on Au. For OAm-Pd and ODT-Pd seed particles, faceted, Au-rich domain NPs and impeded core-shell NPs were obtained, respectively. This is related to the high surface energy of the small Pd seed particles (⌀ ≈ 5-7 nm). The metal distribution of all bimetallic NPs was analyzed by extended (aberration-corrected) transmission electron microscopy (HR-TEM, HAADF-STEM, EDX mapping, ED). The Au and Pd NPs, as well as the ODT-Au@Pd and OAm-Pd@Au heteroparticles, catalyze the reduction of 4-nitrophenol to 4-aminophenol with borohydride. The catalytic activity is dictated by the particle structure. OAm-Au@Pd heteroparticles with faceted Au domains had the highest activity because of a mixed Au-Pd surface structure, while ODT-Au@Pd NPs, where the active Au core is covered by a Pd shell, had the lowest activity.

The thermoelectric properties of melt processed conductive nanocomposites consisting of an insulating polypropylene (PP) matrix filled with singlewalled carbon nanotubes (CNTs) and copper oxide (CuO) were evaluated. An easy and cheap route to switch p-type composites into n-type was developed by adding polyethylene glycol (PEG) during melt mixing. At the investigated CNT concentrations of 0.8 wt% and 2 wt% (each above the electrical percolation threshold of ∼0.1 wt%), and a fixed CuO content of 5 wt%, the PEG addition converted p-type composites (positive Seebeck coefficient (S)) into n-type (negative S). PEG was also found to improve the filler dispersion inside the matrix. Two composites were prepared: P-type polymer/CNT composites with high S (up to 45 mV/K), and n-type composites (with S up to −56 mV/K) through the addition of PEG. Two prototypes with 4 and 49 thermocouples of these p- and n-type composites were fabricated, and delivered an output voltage of 21 mV and 110 mV, respectively, at a temperature gradient of 70 K.

The synthesis of in situ polymer-functionalized anatase TiO2 particles using an anchoring block copolymer with hydroxamate as coordinating species is reported, which yields nanoparticles (≈11 nm) in multigram scale. Thermal annealing converts the polymer brushes into a uniform and homogeneous carbon coating as proven by high resolution transmission electron microscopy and Raman spectroscopy. The strong impact of particle size as well as carbon coating on the electrochemical performance of anatase TiO2 is demonstrated. Downsizing the particles leads to higher reversible uptake/release of sodium cations per formula unit TiO2 (e.g., 0.72 eq. Na+ (11 nm) vs only 0.56 eq. Na+ (40 nm)) while the carbon coating improves rate performance. The combination of small particle size and homogeneous carbon coating allows for the excellent electrochemical performance of anatase TiO2 at high (134 mAh g−1 at 10 C (3.35 A g−1)) and low (≈227 mAh g−1 at 0.1 C) current rates, high cycling stability (full capacity retention between 2nd and 300th cycle at 1 C) and improved coulombic efficiency (≈99.8%).

Zink Oxid Nanopartikel (ZnO-NP) können ihre genotoxische Wirkung direkt durch Interaktion der Partikel mit zellulären Strukturen oder indirekt über ihre Dissoziation zu Zn2+ vermitteln. Ziel dieser Studie war es, in vitro die genotoxische Wirkung sowie die zugrundeliegenden[for full text, please go to the a.m. URL], 86. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie

29th European Photovoltaic Solar Energy Conference and Exhibition; 1277-1281, Printed inks or pastes based on silver nanoparticles are promising alternatives for the metallization of temperature-sensitive silicon solar cells. We show that the sintering of silver nanoparticles strongly depends on the nature of the capping agent used to stabilize the particles during synthesis and in ink formulation. Particles capped by agents containing nitrogen as coordinative anchor group (between agent and silver surface) show poorer sintering under same conditions compared with particles capped by oxygen containing stabilizers. Polymers also hinder sintering more than shorter oligomers. In order to avoid unwanted spreading of the metal ink or paste during printing, the formulation has to be adjusted to the requirements given by the surface. If samples covered by a layer of indium tin oxide are stored in air, the surface energy rapidly decreases, dropping by around 30-50 % within one day. Thus, wettability and the work of adhesion also become poorer. This has to be taken into account by formulating inks for metallization on ITO layers.

Einleitung: Zinkoxid (ZnO)- und Zirkoniumoxid (ZrO2)-Nanopartikel sind zunehmend in Alltagsprodukten wie beispielsweise Wandfarbe und Sonnencreme enthalten und werden zudem in Autoabgasen freigesetzt. Über die Auswirkung auf das respiratorische Epithel als erstes Kontaktgewebe ist wenig bekannt.[for full text, please go to the a.m. URL], 84. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie

Nanopartikel (NP) können für Menschen gesundheitsschädlich sein. Zink Oxid (ZnO) ist eines der meist synthetisierten Nanopartikel und findet zunehmende Verwendung nicht nur in Industrie und Medizin sondern auch in diversen Kosmetikprodukten. Um Gesundheitsrisiken einschätzen zu können,[for full text, please go to the a.m. URL], 84. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie

Introduction: Zinc oxide (ZnO) and zirconium oxide (ZrO2) nanoparticles are increasingly contained in everyday products like wall paint, sunscreen and are released within car exhaust fumes. The pathologic impact of these particles on the respiratory epithelium is not well investigated so far. It remains[for full text, please go to the a.m. URL], 84th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

Engineering materials with specific physical properties has recently focused on the effect of nanoscopic inhomogeneities at the 10 nm scale. Such features are expected to scatter medium and long-wavelength phonons lowering thereby the thermal conductivity of the system without simultaneously decreasing the charge transport (phonon-glass electron-crystal concept). A new Zn1+xSb nanophase obtained by a wet chemical approach was densified by spark plasma sintering (SPS). Investigations on compounds subsumed as "Zn4Sb3" always suffer from its low thermal stability and the contamination of the nanoparticles with solvents and additives used in the synthesis. In order to gain insight into this compound's electronic properties we investigated a material free from remnants of the synthesis but contaminated with a small amount of well-characterized decomposition product, i.e., ZnSb. To investigate the influence of the sintering process on the densified samples, different SPS conditions were applied. Four different conditions were used with heating rates between 160° and 230 °C/min, sintering temperatures between 130 and 190 °C and sintering times between 3 and 6 min. Powders from the surface of the pellets were subject to powder X-ray diffraction (XRD) yielding information about the surface composition. Small pieces of the pellets were also characterized using high-energy synchrotron radiation scattering in order to reveal the phase compositions inside the pellets. Small changes in the sintering conditions of the samples were found to have a large influence on the resulting sample compositions. In addition, the phase compositions on the surface differ significantly from the ones inside the pellets which show a much higher grade of decomposition. The density and morphology of the obtained pellets have been investigated by means of laser microscopy and scanning electron microscopy (SEM). The low density and porosity of the different pellets is a result of the graphite pressing tool which has to be used to ensure the temperature control during the SPS process.