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Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2+ CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1and 850 h−1were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]

Even though Pd-H system has been known since the nineteenth century, it is still of interest to scientists. Pd thin film electrode (called as a Limited Volume Electrode – LVE) is able to electrosorb hydrogen form aqueous (acid, base) and non-aqueous electrolytes (e.g. ionic liquids). Therefore Pd-H is an irreplaceable model system for the study of hydrogen electrosorption in different media. The paper presents: (1) short overview of the study of hydrogen sorption in Pd, (2) the detailed description of the electrochemical measurement methods and (3) the equations for the determination of hydrogen electrosorption charges needed to hydrogen electrosorption isotherms creation. The presented approach can be applied for laboratory work. The results show that Pd-LVE can be effectively used as a model system before the studies of multicomponent hydrogen storage alloys (e.g. AB5 alloys). [ABSTRACT FROM AUTHOR]

In this paper a quaternary ammonium based room temperature ionic liquid (IL) trioctylmethylammonium hydrogen phthalate has been reported as promising extractant for separation of U(VI) from other metal ions from aqueous media. The IL was synthesized via metathesis route and characterized using various techniques such as hydrogen nuclear magnetic resonance, electron spray ionization mass spectrometry and infra red etc. The newly synthesized IL was evaluated for extraction of U(VI), Th(IV), La(III), Y(III), Nd(III) and Fe(III) from aqueous solutions and follow the order: U(VI) > Th(IV) > Fe(III) > Y(III) >> Nd(III) ~ La(III). [ABSTRACT FROM AUTHOR]

Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2 + CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3 dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1 and 850 h−1 were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on green chemical functionalization of hydrogen-terminated boron-doped diamond (BDD) surfaces with aryldiazonium salts in the presence of ionic liquids. The reaction takes place at room temperature in air without any external bias in either hydrophobic (1-butyl-3-methylimidazolium hexafluorophosphate) or hydrophilic (1-butyl-3-methylimidazolium methyl sulfate) ionic liquids. The resulting surfaces were characterized using X-ray photoelectron spectroscopy and electrochemical measurements. [Copyright &y& Elsevier]

Intramolecular H-atom-transfers (IHTs) in curcumin (enol) and its mimic, 1,6-heptadiene-3,5-dione (enol), in ground state and excited state were investigated by ab initio and CIS methods in this paper. It is revealed that double ortho-methoxy-phenolic rings have little effect on the IHT barrier of curcumin, and the IHT barrier of curcumin in ground state is much lower than those of other IHT models, such as 9-hydroxyphenalen-1-one and perylenequinonoid pigments. More interestingly, the IHT barrier of 1,6-heptadiene-3,5-dione (enol) in the singlet excited state is nearly 25kJ/mol higher than that in the ground state, which is very unique in IHT phenomenon. The unexpected IHT behavior of 1,6-heptadiene-3,5-dione (enol) is explained in terms of O–O distance, charge variation of H-atom, and flexibility of the structure. [Copyright &y& Elsevier]

In this paper, we discuss the progress of nitride and oxide semiconductor nanostructures for hydrogen gas sensing. The use of catalyst metal coatings on GaN, InN and ZnO nanowires is found to greatly enhance the detection sensitivity. Pt- and Pd-coated GaN nanowires biased at small voltages show large changes in currents upon exposure to H2 gas at concentrations in the ppm range. Improvements in growth techniques for InN nanostructures have produced nanobelts and nanorods capable of hydrogen detection down to 20 ppm after catalyst coating. Functionalized ZnO nanorods were also investigated for hydrogen detection, but did not generate a relative response as high as that for the nitride-based sensors. All sensors tested exhibited no response at room temperature upon exposure to various other gases including O2, C2H5, N2O and CO2. The high surface-to-volume ratio of nanowires and the ability to use simple contact fabrication schemes make them attractive for hydrogen sensing applications. [ABSTRACT FROM AUTHOR]

Abstract: Perdeuterated pyridinium chloride–DMSO-d6 is an effective solvent system for whole cell biomass dissolution and NMR characterization. Employing this solvent system, semi-quantitative 13C–1H heteronuclear single quantum correlation (HSQC) spectroscopy of untreated, steam, dilute acid and lime pretreated poplar biomass samples was readily accomplished. In an effort to demonstrate the efficacy and usefulness of this fairly new characterization technique, relative spectral intensities of the untreated and pretreated biomass samples were evaluated and compared. From the relative signal intensities of hemicelluloses in each system it was observed that hemicelluloses are being removed in various pretreatment conditions, but complete dissolution of hemicellulose was observed only with acid pretreatment. The relative changes in lignin subunits after pretreatment were estimated from the volume integration of resolved cross peaks of various lignin subunits. The degradation of lignin was observed in all pretreatments, though more significant changes were noticed after dilute acid and lime pretreatment. HSQC analysis results were in agreement with the composition analysis of pretreated biomass samples. Thus, this methodology broadens the application of whole cell NMR analysis in biofuel research. [Copyright &y& Elsevier]