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RuNi nanoparticles supported on a metal-organic framework (RuNi@MOF) and formed in situ from a ruthenium complex enclosed inside a nickel-based MOF act as a highly active catalyst for the Guerbet reaction of ethanol to 1-butanol, providing turnover numbers up to 725 000 Ru

Linear octenes were produced in high (70–85%) selectivity from oligomerization of liquid 1-butene using carbon-supported cobalt oxide catalysts in a continuous flow reactor. The liquid products were characterized by two-dimensional gas chromatography–mass spectrometry. Above 95% of the oligomers were C8 olefins, with the other products primarily being branched C12 olefins. The linear octene products at a conversion of 9.77% decreased in selectivity according to 3-octene > trans-2-octene > cis-2-octene > 4-octene. Methyl-heptenes including trans/cis-5-methyl-2-heptene > trans/cis-5-methyl-3-heptene > trans-3-methyl-2-heptene (at the lowest conversion) were the other major products summing to 15.6%. The selectivity of linear octenes decreased from 84 to 78% as the conversion increased from 10% to 29%. The product distribution suggests the reaction pathway involves a head-to-head coupling of two 1-butene molecules to form internal linear octenes. Head-to-tail coupling of two 1-butene molecules or a coupling ...

The growth of epitaxial Zn_3P_2 films on III–V substrates unlocks a promising pathway toward high-efficiency, earth-abundant photovoltaic devices fabricated on reusable, single-crystal templates. The detailed chemical, structural, and electronic properties of the surface and interface of pseudomorphic Zn_3P_2 epilayers grown on GaAs(001) were investigated using scanning tunneling microscopy/spectroscopy and high-resolution X-ray photoelectron spectroscopy. Two interesting features of the growth process were observed: (1) vapor-phase P4 first reacts with the Ga-rich GaAs surface to form an interfacial GaP layer with a thickness of several monolayers, and (2) a P-rich amorphous overlayer is present during the entire film growth process, beneath which a highly ordered Zn_3P_2 crystalline phase is precipitated. These features were corroborated by transmission electron micrographs of the Zn_3P_2/GaAs interface as well as density functional theory calculations of P reactions with the GaAs surface. Finally, the valence-band offset between the crystalline Zn_3P_2 epilayer and the GaAs substrate was determined to be ΔE_V = 1.0 ± 0.1 eV, indicating the formation of a hole-depletion layer at the substrate surface which may inhibit formation of an ohmic contact.

This work validates the appropriate application of chemical reaction engineering principles in the successful design of a full-scale industrial trickle bed reactor for a proprietary hydrogenation reaction over a palladium catalyst. After identifying an effective catalyst formulation in a continuous laboratory scale trickle bed reactor, the project team used the same small-scale reactor to generate kinetic data for scale-up. The scale factor from the laboratory to the final design was about 3 × 106. The development effort identified and resolved three important problems: (1) incomplete catalyst wetting of the small catalyst bed, even though the catalyst was diluted with inert fines; (2) lower than economically attractive catalyst productivity; and (3) catalyst deactivation.

Failure analysis of solar cells and model substrates coated with silicon nitride barrier thin films has led to important conclusions regarding the major factors leading to barrier degradation. Data...

Multilayer polymer films composed of a ruthenium terpyridine complex containing poly(p-phenylenevinylene) (Ru-PPV) and sulfonated polyaniline (SPAN) were prepared by a layer-by-layer electrostatic self-assembly deposition. The deposition process was carried out from SPAN solution in water and Ru-PPV in dimethylformamide (DMF). Optical-quality multilayer thin films were obtained. The film growth process was monitored by quartz crystal microbalance, and the surface morphology of the films was studied by atomic force microscopy. It was found that the properties of the multilayer films were dependent on deposition conditions such as the pH of the SPAN solution, the presence of salt in the polymer solutions, and the post-film-forming thermal annealing process. Cross-section transmission electron microscopic images suggested that there was no stratified structure formed in the multilayer films. Photovoltaic cells were fabricated by sandwiching the multilayer films between indium-tin-oxide and aluminum electrodes. The device performances were examined by illumination with AM 1.5 simulated solar light. The power conversion efficiencies of these devices were on the order of 10(-3)%. The maximum incident photon-to-electron conversion efficiency (IPCE) of the devices was found to be approximately 2% at 510 nm, which is consistent with the absorption maximum of the ruthenium complex. This indicates that the photosensitization process is due to the electronic excitation of the ruthenium complex.