Electrolytes formed by ions of similar volumes show better performance in supercapacitor applications.

Global minimum potential energy state can be very challenging to locate in a relatively large atomistic system. Our present work investigates this problem using an example of gold nanoclusters, Au 10 , Au 20 , Au 30 , Au 50 . Nanoscale gold particles (NGPs) contribute heavily life sciences through their applications in diagnostics and therapeutics. NGPs feature manifold atomistic configurations depending on the conditions of synthesis. We apply annealing molecular dynamics (AMD) as an alternative and supplement to the well-established eigenfollowing (EF) geometry optimization. We conclude that the combination of AMD and EF systematically works more efficiently than EF alone. Research Highlights(1) Potential energy surface of a set of gold nanoparticles was investigated.(2) Annealing and eigenfollowing were used to obtain relaxed structures.(3) More efficient scheme for global minimum search was introduced.

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The amino group is important to enhance carbon dioxide capture capabilities of substances, including roomtemperature ionic liquids (RTILs). We report thermodynamics of amination for five organic cations representing different families of RTILs (imidazolium, pyridinium, morpholinium, pyrrolidinium, pyrazolium) and compare all prospective amination sites. We conclude that amination of the cation ring is more favorable than amination of the side chains. Redistribution of electron density due to amination partially correlates with variation of enthalpy and Gibbs free energy, whereas entropic part is similar for all cations and all amination sites. Vibrational frequencies allow for easy distinguishing amination products from reactants and simplify identification of the reaction site (ring or side chain). Formation of strong hydrogen bonds between the amino group and the anions greatly favors amination of RTILs, compared to amination of benzene.

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1) PRAMO, Saint Petersburg, Leningrad oblast, Russian Federation.(2) P.E.S., Vasilievsky Island, Saint Petersburg, Leningrad oblast, Russian Federation. Abstract. Development of new greenhouse gas scavengers is actively pursued nowadays.Volatility-caused solvent consumption and significant regeneration costs associated with the aqueous amine solutions motivate search for more technologically and economically advanced solutions. We hereby used hybrid density functional theory to characterize thermodynamics, structure, electronic and solvation properties of amino-and carboxamido-functionalized C 60 fullerene. C 60 is non-volatile and supports a large density of amino groups on its surface. Attachment of polar groups to fullerene C 60 adjusts its dipole moment and band gap quite substantially, ultimately resulting in systematically better hydration thermodynamics. Reaction of polyaminofullerenes with CO 2 is favored enthalpically, but prohibited entropically at standard conditions. Free energy of the CO 2 capture by polyaminofullerenes is non-sensitive to the number of amino groups per fullerene. This result fosters consideration of polyaminofullerenes for CO 2 fixation.

Recent success of the sodium-ion batteries fosters an academic interest for their investigation. Room-temperature ionic liquids (RTILs) constitute universal solvents providing non-volatility and non-flammability to electrolytes. In the present work, we consider four families of RTILs as prospective solvents for NaBF4 and NaNO3 with an inorganic salt concentration of 25 and 50 mol%. We propose a methodology to rate RTILs according to their solvation capability using parameters of the computed radial distribution functions. Hydrogen bonds between the cations and the anions of RTILs were found to indirectly favor sodium solvation, irrespective of the particular RTIL and its concentration. The best performance was recorded in the case of cholinium nitrate. The reported observations and correlations of ionic structures and properties offer important assistance to an emerging field of sodium-ion batteries. Graphical Abstract Sodium-ion electrolytes.

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