Suzuki–Miyaura reaction and solventfree oxidation of benzyl alcohol by Pd/nitrogen-doped CNTs catalyst

Suzuki–Miyaura C–C coupling reactions were investigated with Pd/nitrogen-doped carbon nanotubes (Pd/N-CNTs) as a catalyst. Also, the same catalyst was examined for the solventfree oxidation of benzyl alcohol to benzaldehyde. Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized from 1-ferrocenylmethyl(2-methylimidazole) and benzophenone via a chemical vapour deposition technique. Acetonitrile was used as a solvent and source of both carbon and nitrogen constituents of N-CNTs. Pd nanoparticles (Pd NPs) were successfully dispersed on N-CNTs via a metal organic chemical vapour deposition method. SEM, TEM, XRD, elemental analysis and ICP-OES measurements were used to characterize the nanomaterials. From the TEM analysis, it was observed that Pd NPs were spherical and with particle sizes ranging from 3 to 8 nm. For Suzuki C–C coupling reactions, phenylboronic acid, aryl halide, Pd/N-CNTs catalyst and a base (NaOAc, K₂PO₄, K₂CO₃, NaOH, Et₃N and Na₂CO₃) were used. The optimized experiments indicate that K₂CO₃, as the base, and ethanol/water (1:1 v/v, 10 mL) mixture, as a solvent, are the best reaction conditions. The solventfree oxidation reactions of benzyl alcohol were also done with Pd/N-CNTs catalyst and benzyl alcohol as a substrate. In both sets of reactions, C–C coupling and oxidation, the increase in pyrrolic nitrogen species was found to be responsible for higher catalytic activities of Pd/N-CNT catalysts, and this was attributed to the ease of Pd NP dispersion on N-CNTs, relative to pristine CNTs. Also, the higher catalytic activity of Pd/N-CNTs could be ascribed not only to the smaller Pd NP size or surface area, but to also the surface properties and the nature of the support when compared with the undoped counterpart, Pd/CNTs.     

On the horns of a dilemma: does more funding for research lead to more research or a waste of resources that calls for optimization of researcher portfolios? An analysis using funding acknowledgement data

Increasing pressure on budgets of funding bodies has led to discussion of how to make financial resources go further, and to the concern that some researchers take more money from funding bodies for a particular project than needed, a practice that has been termed “double-dipping”. Some evidence has emerged that this might be occurring, and in this context of suddenly increased funding scarcity, albeit in a system with greater forms of support, a proposal has been made that funding bodies monitor and manage individual researcher portfolios to optimize resource use. Our paper provides evidence relevant to both the “double dipping” issue and the proposal to manage portfolios. We show that where certain pre-conditions for “double dipping” are met (i.e. when funding comes from more than organisation, and the organisations fund research in a very similar area), and where therefore an argument to monitor researcher portfolios might be applicable, the research produced under these conditions has greater citation impact. We query the claim that when more funding is acknowledged this is inherently undesirable and we express our doubts that subjecting the allocation of funding to researchers to a bureaucratic management process will necessarily increase the impact of research.     

Fabrication and characterization of porous Co–Cr–Mo/58S bioglass nano-composite by using NH4HCO3 as space-holder

In the present study, Co–Cr–Mo/58S porous nano-composites were successfully fabricated by the use of space-holder and powder metallurgy techniques. The cold compacted Samples were heated at 175 °C for 2 h and then was raised to 1250 °C and held for 2 h. Scanning electron microscope (SEM) and optical microscope (OM) images of porous samples showed interconnected, isolated pores and appropriate range of pore sizes. The results of compressive strength and Young's modulus were in the range of 33–566 MPa and 0.19–4.46 GPa, respectively. In particular, the compressive strength and Young's modulus at the porosity of 38.5% were found to be similar to those of bone. The SEM images, pH values and Fourier-transform infrared spectroscopy (FTIR) results showed that apatite crystallites were formed on the surface of sample with 38.5% porosity during immersion in simulated body fluid which revealed bioactivity of this sample. In vitro cytocompatibility of the sample with 38.5% porosity was evaluated and cell growth was examined. SEM images revealed that cells grew on the surface and inside the pores. The present investigation has shown that this porous nano-composite is a promising biomaterial for bone tissue engineering by virtue of its porous structure, appropriate mechanical properties, bioactivity and biocompatibility.     

Selective dispersive liquid–liquid microextraction and preconcentration of Ni(II) into a micro droplet followed by ETAAS determination using a yellow Schiff's base bisazanyl derivative

A simple, rapid and sensitive method was developed for the selective separation and preconcentration of Ni(II) using dispersive liquid–liquid microextraction, by a yellow Schiff's base bisazanyl derivative, as a selective complexing agent. In this method, a mixture of 45 μL chloroform (extraction solvent) and 450 μL tetrahydrofuran (dispersive solvent) is rapidly injected by syringe into a 5 mL aqueous sample containing 3% (w/v) sodium chloride and an appropriate amount of the Schiff's base. As a result, a cloudy solution is formed by entire dispersion of the extraction solvent into the aqueous phase. After centrifuging for 5 min at 5000 rpm, the sedimented phase is directly injected into the electrothermal atomic absorption spectrometry for Ni(II) determination. Some important parameters, such as kind and volume of extraction and dispersive solvents, extraction time, salt effect, pH and concentration of the chelating agent have been optimized. Under the optimum conditions, the enrichment factor for the presented method is 138. The calibration curve was linear over a nickel concentration range of 10–50 ng mL^? 1. The detection limit and relative standard deviation were 0.04 ng mL^? 1 and 2.1%, respectively. The method was successfully applied to the extraction and determination of Ni(II) in different water samples.     

Noble metal promoted Ni–Cu/La2O3–MgO catalyst for renewable and enhanced hydrogen production via steam reforming of bio-based n-butanol: effect of promotion with Pt,Ru and Pd on catalytic activity and selectivity

Clean Technologies and Environmental Policy - Currently, production of high-purity hydrogen (H2) in a viable and sustainable manner is highly sought. H2 generation is possible by water splitting or...     

Structure and surface morphology of Si1 — x Ge x layers grown on Si/sapphire by molecular beam epitaxy using a sublimation silicon source and gaseous germanium source

Si_{1 ? x} Ge _x epilayers have been grown on silicon-on-sapphire structures by molecular beam epitaxy using a sublimation silicon source and gaseous germanium source. Si_{1 ? x} Ge _x layers grown directly on sapphire substrates had poorer structural perfection, so Si buffer layers were used in subsequent growth runs. Using X-ray photoelectron spectroscopy, we determined the concentration-depth profiles of Si, Ge, and background impurities across the layers. Varying the Si buffer thickness in the range 50–300 nm was shown to have no effect on the structure of the SiGe layers. Single-crystal SiGe layers were obtained at substrate temperatures in the range 360–410°C. Varying the germanium concentration in the range 5–25% had no effect on the structure of the layers but slightly increased their roughness.