17 research outputs found

    CVD graphene growth on a surface of liquid gallium

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    Abstract This paper presents the results of the experiments on graphene growth on the surface of a liquid metal gallium that appeared to have the catalytic ability in respect to carbon atoms. Due to the absence of crystal lattice, the liquid catalyst does not influence the graphene formation and as a result, the latter has uniform hexagonal structure. The work comprises the data on graphene synthesis on the surface of pure gallium with different precursors and on the surface of pre-treated gallium without any precursor. Obtained materials were characterized by RAMAN, TEM, SEM and FT-IR techniques

    Single-Site Organozirconium Catalyst Embedded in a Metal–Organic Framework

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    A structurally well-defined mesoporous Hf-based metal–organic framework (Hf-NU-1000) is employed as a well-defined scaffold for a highly electrophilic single-site d<sup>0</sup> Zr–benzyl catalytic center. This new material Hf-NU-1000-ZrBn is fully characterized by a variety of spectroscopic techniques and DFT computation. Hf-NU-1000-ZrBn is found to be a promising single-component catalyst (i.e., not requiring a catalyst/activator) for ethylene and stereoregular 1-hexene polymerization

    A Hafnium-Based Metal–Organic Framework as a Nature-Inspired Tandem Reaction Catalyst

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    Tandem catalytic systems, often inspired by biological systems, offer many advantages in the formation of highly functionalized small molecules. Herein, a new metal–organic framework (MOF) with porphyrinic struts and Hf<sub>6</sub> nodes is reported. This MOF demonstrates catalytic efficacy in the tandem oxidation and functionalization of styrene utilizing molecular oxygen as a terminal oxidant. The product, a protected 1,2-aminoalcohol, is formed selectively and with high efficiency using this recyclable heterogeneous catalyst. Significantly, the unusual regioselective transformation occurs only when an Fe-decorated Hf<sub>6</sub> node and the Fe–porphyrin strut work in concert. This report is an example of concurrent orthogonal tandem catalysis

    Comparison of Real-Time and Linear-Response Time-Dependent Density Functional Theories for Molecular Chromophores Ranging from Sparse to High Densities of States

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    © 2015 American Chemical Society. We assess the performance of real-time time-dependent density functional theory (RT-TDDFT) for the calculation of absorption spectra of 12 organic dye molecules relevant to photovoltaics and dye-sensitized solar cells with 8 exchange-correlation functionals (3 traditional, 3 global hybrids, and 2 range-separated hybrids). We compare the calculations with traditional linear-response (LR) TDDFT and experimental spectra. In addition, we demonstrate the efficacy of the RT-TDDFT approach to calculate wide absorption spectra of two large chromophores relevant to photovoltaics and molecular switches. RT-TDDFT generally requires longer simulation times, compared to LR-TDDFT, for absorption spectra of small systems. However, it becomes more effective for the calculation of wide absorption spectra of large molecular complexes and systems with very high densities of states
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