Dibenzo [ghi, mno]fluoranthene, or corannulene, C20H10, is a highly strained hexacyclic hydrocarbon composed of five benzene rings fused into an annulus of fivefold symmetry. The compound crystallizes in space group P2t/c with Z=8 and cell dimensions a=13.260 (7), b= 11.859 (4), e= 16.520 (7) A,, fl= 102.69 (5) ° at 20°C, and a= 13.233 (15), b = 11.785 (15), c= 16.432 (15) A, fl= 102-55 (7) ° at -70°C. Data were obtained by densitometry of doubly integrated oscillation photographs at 20°C, and by diffractometer techniques at -70°C. The structure was solved by a Patterson search procedure. Refinement by block-diagonal least squares brought the final R value to 0.069 for 2013 data observed at 20°C and to 0.074 for 2137 data observed at -70°C. The molecules are cupped with an average dihedral angle of 20"4 ° between least-squares planes defined by the five-and six-membered rings. Averages of chemically equivalent bond distances (corrected for foreshortening due to molecular libration) from two crystallographically independent molecules and two independent sets of data are 1.413 (3) A, for the five bonds in the central ring, 1.391 (4) A, for the five 'spokes', 1.440 (2) A, for the ten peripheral bonds adjacent to the 'spokes', and 1.402 (5) A, for the five outermost peripheral bonds.1147

Currently, the primary source of hydrogen is steam reforming from hydrocarbons. The reformed fuel contains 1-10 % CO.[1, 2] The water gas shift reaction (WGS, CO + H 2 O! H 2 + CO 2 ) and preferential CO oxidation (2 CO + O 2 ! 2 CO 2 ) processes are critical in providing clean hydrogen for polymer electrolyte membrane fuel cells and other industrial applications.[1-3] Conventional WGS catalysts (e.g., Cu on zinc oxide) meet the needs of large stationary applications. [4] Improved air-tolerant, cost-effective WGS catalysts for lower-temperature processing are needed to enable mobile fuel-cell applications. [1][2][3]5] Recently, Au/CeO 2 and Cu/CeO 2 materials were reported to be very promising catalysts for the lower-temperature WGS reaction. [6,7] There is no generally accepted picture for the role of ceria and the metal in the WGS reaction. The existence and role of reduced metal nanoparticles versus cationic metal centers (e.g., Au d+ ) are debated. [5][6][7] Very recent in situ measurements by near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy show that Cu d+ and Au d+ species are not stable under the typical conditions of the WGS reaction.

The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOx emissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of the small‐pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition‐metal/SSZ‐13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtII and PdII. Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl‐nitrosyl palladium complex in chabazite micropore.

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Catalysts H 2000Platinum Monolayer on Nonnoble Metal-Noble Metal Core-Shell Nanoparticle Electrocatalysts for O2 Reduction. -New O2 electrocatalysts with a high activity and very low noble metal content consisting of Pt monolayers deposited on the surfaces of carbon-supported non-noble-noble metal core-shell nanoparticles such as Pt/Au/Ni, Pt/Pd/Co, and Pt/Pt/Co are synthesized. The core-shell nanoparticles are formed by impregnation of Vulcan X-72C carbon with mixed solutions of noble and non-noble metal salts such as AuCl3, NiCl2, K2PtCl4, CoCl2, and PdCl2. A Pt monolayer is deposited by galvanic displacement of a Cu monolayer deposited at underpotentials. The mass activity of all three Pt monolayer electrocatalysts is more than an order of magnitude higher than that of a commercial Pt-C electrocatalyst. Because the new catalysts contain only a fractional amount of Pt and a very small amount of another noble metal, the cost of fuel cells could be lowered considerably. -(ZHANG, J.; LIMA, F. H. B.; SHAO, M. H.; SASAKI, K.; WANG, J. X.; HANSON, J.; ADZIC*, R. R.; J.

Oxides. -Structural and electronic properties of nanoparticles of the title solid solutions prepared by a reverse microemulsion method are characterized by XRD, XAFS, Raman spectroscopy, and DFT calculations. The Cu atoms embedded in ceria have an oxidation state higher than those of the cations in Cu2O or CuO. The lattices of the title systems still adopt a fluorite-type structure but are highly distorted. The doping of CeO 2 with Cu introduces a large strain into the oxide lattice and favors the formation of O vacancies. The chemical activities of the prepared nanoparticles are characterized by the reactions with H2 and O2. The reduction of the solid solutions is completely reversible without generation of significant amounts of CuO or Cu2O phases during reoxidation. -(WANG, X.; RODRIGUEZ*, J. A.; HANSON, J. C.; GAMARRA, D.; MARTINEZ-ARIAS, A.; FERNANDEZ-GARCIA, M.; J.

Nur mit Oxid: Ce0.8Ni0.2O2−y ist ein ausgezeichneter Katalysator für die Dampfreformierung von Ethanol (siehe Diagramm). Metall‐Oxid‐Wechselwirkungen beeinflussen die elektronischen Eigenschaften kleiner Nickelpartikel, die unter den Reaktionsbedingungen am Katalysator vorliegen, und unterdrücken die Methanbildung. In das Ceroxid eingelagertes Nickel führt zu O‐Leerstellen, die den O‐H‐Bindungsbruch in Ethanol und Wasser erleichtern.

We present data that show a cycling transition can be used to detect and image metastable He2 triplet molecules in superfluid helium. We demonstrate that limitations on the cycling efficiency due to the vibrational structure of the molecule can be mitigated by the use of repumping lasers. Images of the molecules obtained using the method are also shown. This technique gives rise to a new kind of ionizing radiation detector. The use of He2 triplet molecules as tracer particles in the superfluid promises to be a powerful tool for visualization of both quantum and classical turbulence in liquid helium.