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The performance of metal-organic frameworks in gas chromatographic separation investigations has been widely study in recent years. However, to use chromatographic methods to determine materials properties of metal-organic frameworks instead of using them just for analyte separations is a field still largely unexplored. The presented study has been conducted to quantify the systematic changes in the interaction of a series of related unbranched aliphatic analytes (C2-C10) with HKUST-1 as the stationary phase not only to obtain information about the MOF analyte interaction strength but also to gain materials parameters characterizing the MOF system, like its response to non-specific interactions. Thermodynamic as well as by kinetic parameters governing the adsorption process were determined using various chromatographic evaluation techniques. The method of inverse chromatography was used to derive the generic susceptibility of HKUST-1 to aliphatic methylene groups and to determine interfacial energy contributions of the intrinsic surface of the porous material. [ABSTRACT FROM AUTHOR]

Short GC capillary columns were coated with micro particles of the two isoreticular pillared-layer frameworks (PLFs) [Cu 2 (cam) 2 (dabco)] and [Cu 2 (cam) 2 (bipy)] (cam 2− = (+)-camphoric acid, dabco = 1,4-diazabicyclo[2.2.2]octane, bipy = 4,4′-bipyridine) by the technique of the so called “Controlled SBU Approach”. It is demonstrated that the small pore openings of [Cu 2 (cam) 2 (dabco)] enable size dependent gas chromatographic separations which were not observed on [Cu 2 (cam) 2 (bipy)]. In some cases the interaction with the smaller pore system lead to unusual peak broadening. Both compounds offer excellent properties for the high resolution separation of light hydrocarbons including isomers. Chromatographic parameters, including resolution factors and selectivities, as well as thermodynamic data characterizing the interaction between the stationary phase and the analytes were determined from the temperature-dependent retentions times. Furthermore, isothermal measurements were used for the calculation of diffusion constants of selected analytes in the mobile phase and in the [Cu 2 (cam) 2 (dabco)] and [Cu 2 (cam) 2 (bipy)] structures. [ABSTRACT FROM AUTHOR]

Highlights: [•] The metal–organic framework [Cu2(bdc)2(dabco)] was synthesized via controlled SBU-approach and a capillary column was coated with it. [•] Light hydrocarbons were separated by the [Cu2(bdc)2(dabco)]-coated column and their heats of adsorption were determined. [•] From kinetic investigations the relation between mass transfer and plate height was determined. [ABSTRACT FROM AUTHOR]

This study concerns an application of spongin-based scaffolds of commercial sponge origin as a naturally structured precursor of carbon material. Further functionalization with cobalt via a simple sorption-reduction method resulted in the preparation of novel catalysts tested in oxidation-reduction reactions. The structure and chemical composition of the prepared materials were investigated in detail, demonstrating the presence of carbonized fibers tightly covered with a metal-containing phase mainly composed of Co 3 O 4. The fibrous structure with open porous canals provides good accessibility for substrates to the surface of the catalysts. Biocarbon material obtained at 600 °C exhibited good catalytic ability in the oxidation of styrene (with high selectivity for the formation of styrene oxide) and rhodamine B compared with other prepared catalysts and biocarbons. Interestingly, all of the prepared materials exhibit favorable activity in the reduction of 4-nitrophenol. A reusability study showed good activity even after the fifth catalytic cycle in both oxidation and reduction reactions. The study proved the adaptability of spongin-based scaffolds to prepare biocarbons with high potential to be used as a support for various catalytic applications. [Display omitted] • Commercial sponge skeletons were transformed into functional catalysts. • Carbonized scaffolds were metallized with cobalt oxide using a simple method. • All prepared solids exhibit superior catalytic performance in nitroarene reduction. • Good performance in selective oxidation of styrene and rhodamine B was obtained. • Mechanisms for the presented reduction and oxidation reactions are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Broad survey of hydrotalcite based methanation catalysts with period IV additives. • A large array of various catalysts with one Ni to additive atomic ratio generated. • Significant increase of activity by Mn, Fe; being superior to Cr, Co, Cu, Zn, Ga. • Investigation at elevated pressure (20 bar). Because of their simplicity, bimetallic nickel catalysts are a rational step to further develop improved CO 2 -methanation catalysts suitable for specific applications and feed gas situations. In this study, hydrotalcite-based catalysts incorporating a second metal from the 4th period (chromium, manganese, iron, cobalt, copper, zinc and gallium) were synthesized, characterized (ICP-OES, XRD, BET, XPS) and performance tested under comparable conditions. The study aims at the clarification of inconsistencies regarding these additives found in the literature by ensuring comparability as good as possible. To achieve this goal the catalysts were tested using the same reactor, were prepared by the same type of synthesis possessing the same atomic ratio of Ni to the potential promoter element. In catalytic tests, performed at atmospheric pressure and at 20 bar, all catalysts were active in respect to CO 2 hydrogenation. While Cu, Zn, and Ga acted as inhibitors, reducing the activity approximately by half, Fe and Mn proved to be very active promotors. The catalyst without promotor shows 80 % yield at 400 °C whereas the iron containing catalyst reaches this value already at 320 °C, but undergoes a irreversible loss at high temperatures (20 % loss after being exposed to 480 °C). In contrast, the manganese containing catalyst possesses a significantly improved activity without showing such a deactivation process, indicating a high level of stability. [ABSTRACT FROM AUTHOR]

This work focuses on the determination of the standard molar enthalpies of formation Δ f H °(298) of the lithium silicides Li 7 Si 3 and Li 12 Si 7 . For this purpose the hydrogenation/dehydrogenation equilibria in the system Li-Si-H were investigated at three different temperatures (450 °C, 475 °C, 500 °C) using a Sieverts type apparatus. The measurements are based on two different sample types: (i) pure silicide Li 7 Si 3 (Li 2.33 Si) and (ii) a stoichiometric mixture of lithium hydride and silicon in the ratio of Li:Si = 2.33:1. The calculation of the standard enthalpies of formation by using the slopes of the classical Van't Hoff plot results in uncertainties of at least 10%. Due to this relatively large error, an alternative evaluation method based on the linking of the hydrogen equilibrium pressures p eq (H 2 ) from the sorption measurements with recently published precise heat capacity and entropy data of the lithium silicides was applied. The obtained values for the standard enthalpy of formation amount to Δ f H °(298) = (−25.3 ± 0.3) kJ/(mol atom) for Li 7 Si 3 and Δ f H °(298) = (−23.5 ± 0.3) kJ/(mol atom) for Li 12 Si 7 exhibiting strongly reduced uncertainties. [ABSTRACT FROM AUTHOR]

A consistent thermodynamic description of the Li-Si system and its extension to the Li-Si-H system is developed based on comprehensive Calphad-type assessment of all pertinent thermodynamic and phase equilibrium data. Key experiments were performed by measuring the equilibrium pressure for the hydrogenation of the lithium silicides at 773 K, 748 K and 723 K. The Gibbs energy functions of the Li-Si compounds developed in this work are validated by direct comparison of the predicted hydrogen pressure with experimental data. The interrelation of the hydrogen absorption pressure with the calculated Li-Si-H ternary phase diagram is also elucidated. The calculated Li-Si phase diagram, both on chemical potential and composition scale, is well supported by the entity of experimental data. In addition to the stable intermetallics Li 17 Si 4 , Li 16.42 Si 4 (Li 4.11 Si), Li 13 Si 4 , Li 7 Si 3 , Li 12 Si 7 , LiSi also metastable Li 15 Si 4 and an approximate for amorphous Si(Li) is included in the thermodynamic modeling. Qualitative prediction of open-circuit voltage curves during metastable lithiation/delithiation of Si as advanced anode material for Li-ion batteries at room temperature is made. [ABSTRACT FROM AUTHOR]

Abstract: With the increasing complexity of model systems for the investigation of antibacterial effects of nanoparticles, the demands on appropriate analysis methods are rising. In case of biofilms grown on small particles, the high inhomogeneity of the samples represents a major challenge for traditional biofilm analysis. For this purpose, we developed a new calorimetric method which allows non-invasive and real-time investigation of the effects of nanoparticles on beads-grown biofilms which meets the requirements for an increased sample throughput. The method employs a newly developed chip calorimeter that is able to detect changes in the metabolic activity of biofilm samples within minutes. Using this novel device, the antibacterial effect of silver nanoparticles on Pseudomonas putida biofilms grown on agarose beads was investigated. The superparamagnetic properties of the embedded particles within the agarose beads allow an automated sample throughput. Growth inhibition and inactivation effects of silver nanoparticles (AgNPs) on biofilm bacteria were quantified by analyzing the metabolic heat production rate. As a result, a concentration dependent manner of growth inhibition and inactivation was found demonstrating the suitability and sensitivity of the methodology. [Copyright &y& Elsevier]

Abstract: Thermodynamic and constitutional data of the Li–Si system were critically reviewed and the importance of using original experimental data is highlighted, as opposed to a previous thermodynamic modeling of this system. The C p-functions of all Li–Si compounds were experimentally determined for 2–900 K and those for pure solid Li and Si from 0 to 298 K from experimental literature data. The reliability of solubility data for the dilute solution of Si in liquid Li was assessed by thermodynamic considerations. A consistent thermodynamic description of all solid phases in the Li–Si system from 0 K to high temperature is developed, jointly with that for the liquid phase, using the Calphad method. The first calculated and validated Li–Si phase diagram from 0 K to liquidus temperatures is presented. Experimental liquidus data are found to be inconsistent with well established experimental thermodynamic data and further research is required. [Copyright &y& Elsevier]

Abstract: As a representative of the IRMOF series, MOF-5 was deposited onto self-assembled monolayer modified metal and fused silica surfaces applying the controlled SBU approach (CSA) (SBU – secondary building unit). Although the controlled SBU approach was already used in some cases to deposit IRMOFs and other MOF (metal–organic framework) types on surfaces, this contribution is the first study concerned with basic processes of the deposition of IRMOFs onto SAM (self-assembled monolayers) coated substrates, like the carboxylate exchange between SBU precursor and SAM, the influence of different substrates, or the morphology differences resulting from different cyclic preparation procedures. The deposition of the first SBU layer (basic zinc perfluoromethylbenzoate) onto the surface and the carboxylate exchange during CSA was demonstrated by infrared reflection–absorption spectroscopy. The various aspects of the MOF deposition, such as the crystalline growth, the element distribution, the porosity, and the morphology of the thin films were addressed by powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), nitrogen cryo-adsorption measurement, and scanning electron microscopy (SEM). [Copyright &y& Elsevier]

Abstract: Ammonia borane has attracted considerable interest in the last years as a hydrogen source material due to its high hydrogen content of 19.6wt%. The release of hydrogen from solid ammonia borane leads to the formation of polymeric waste products. In order to make ammonia borane a promising material for applications in the hydrogen economy, an energy-efficient procedure for the regeneration of from these waste products should be developed. A concept for such a procedure is outlined. The proposed recycling strategy is described by a self-contained reaction scheme, in which only BNH-waste and molecular hydrogen are consumed. The key step in this strategy is the hydrodechlorination of a base adduct with molecular hydrogen in the presence of the base in excess. The base used is only an auxiliary reactant and can be recovered in principle by the thermal decomposition of the obtained baseHCl adduct. The criteria for a proper selection of the base, which is the critical parameter for the development of an energy-efficient regeneration procedure, are discussed. [Copyright &y& Elsevier]