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Publisher: Washington, DC : American Chemical Society × WGL Institute: INP ×

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Now showing 1 - 4 of 4
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    Functional Nanosheet Synthons by Covalent Modification of Transition-Metal Dichalcogenides
    (Washington, DC : American Chemical Society, 2017) Presolski, Stanislav; Wang, Lu; Loo, Adeline Huiling; Ambrosi, Adriano; Lazar, Petr; Ranc, Václav; Otyepka, Michal; Zboril, Radek; Tomanec, Ondřej; Ugolotti, Juri; Sofer, Zdeněk; Pumera, Martin
    We report on the facile preparation of versatile MoS2-thiobarbituric acid conjugates, which, in addition to excellent electrochemical behavior, can serve as nanosheet platforms for further functionalization in a multitude of applications. We show that chemically exfoliated MoS2 was extensively modified with up to 50% surface coverage, while maintaining its metallic character, and that the strategy can be extended to MoSe2, WS2, and WSe2. The covalent functionalization endowed the materials not only with good aqueous dispersibility, but also with improved hydrogen evolution reaction (HER) activity, as well as promise in the oxidative detection of DNA nucleobases in solution.
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    The Role of Connectivity on Electronic Properties of Lead Iodide Perovskite-Derived Compounds
    (Washington, DC : American Chemical Society, 2017) Kamminga, Machteld E.; de Wijs, Gilles A.; Havenith, Remco W. A.; Blake, Graeme R.; Palstra, Thomas T.M.
    We use a layered solution crystal growth method to synthesize high-quality single crystals of two different benzylammonium lead iodide perovskite-like organic/inorganic hybrids. The well-known (C6H5CH2NH3)2PbI4 phase is obtained in the form of bright orange platelets, with a structure comprised of single 〈100〉-terminated sheets of corner-sharing PbI6 octahedra separated by bilayers of the organic cations. The presence of water during synthesis leads to formation of a novel minority phase that crystallizes in the form of nearly transparent, light yellow bar-shaped crystals. This phase adopts the monoclinic space group P21/n and incorporates water molecules, with structural formula (C6H5CH2NH3)4Pb5I14·2H2O. The crystal structure consists of ribbons of edge-sharing PbI6 octahedra separated by the organic cations. Density functional theory calculations including spin-orbit coupling show that these edge-sharing PbI6 octahedra cause the band gap to increase with respect to corner-sharing PbI6 octahedra in (C6H5CH2NH3)2PbI4. To gain systematic insight, we model the effect of the connectivity of PbI6 octahedra on the band gap in idealized lead iodide perovskite-derived compounds. We find that increasing the connectivity from corner-, via edge-, to face-sharing causes a significant increase in the band gap. This provides a new mechanism to tailor the optical properties in organic/inorganic hybrid compounds.
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    Materials cartography: Representing and mining materials space using structural and electronic fingerprints
    (Washington, DC : American Chemical Society, 2014) Isayev, Olexandr; Fourches, Denis; Muratov, Eugene N.; Oses, Corey; Rasch, Kevin; Tropsha, Alexander; Curtarolo, Stefano
    As the proliferation of high-throughput approaches in materials science is increasing the wealth of data in the field, the gap between accumulated-information and derived-knowledge widens. We address the issue of scientific discovery in materials databases by introducing novel analytical approaches based on structural and electronic materials fingerprints. The framework is employed to (i) query large databases of materials using similarity concepts, (ii) map the connectivity of materials space (i.e., as a materials cartograms) for rapidly identifying regions with unique organizations/properties, and (iii) develop predictive Quantitative Materials Structure-Property Relationship models for guiding materials design. In this study, we test these fingerprints by seeking target material properties. As a quantitative example, we model the critical temperatures of known superconductors. Our novel materials fingerprinting and materials cartography approaches contribute to the emerging field of materials informatics by enabling effective computational tools to analyze, visualize, model, and design new materials.
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    Plasma Technology: An Emerging Technology for Energy Storage
    (Washington, DC : American Chemical Society, 2018) Bogaerts, Annemie; Neyts, Erik C.
    Plasma technology is gaining increasing interest for gas conversion applications, such as CO2 conversion into value-added chemicals or renewable fuels, and N2 fixation from the air, to be used for the production of small building blocks for, e.g., mineral fertilizers. Plasma is generated by electric power and can easily be switched on/off, making it, in principle, suitable for using intermittent renewable electricity. In this Perspective article, we explain why plasma might be promising for this application. We briefly present the most common types of plasma reactors with their characteristic features, illustrating why some plasma types exhibit better energy efficiency than others. We also highlight current research in the fields of CO2 conversion (including the combined conversion of CO2 with CH4, H2O, or H2) as well as N2 fixation (for NH3 or NOx synthesis). Finally, we discuss the major limitations and steps to be taken for further improvement.