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41.
A Doping Technique that Suppresses Undesirable H2 Evolution Derived from Overall Water Splitting in the Highly Selective Photocatalytic Conversion of CO2 in and by Water 下载免费PDF全文
Prof. Dr. Kentaro Teramura Zheng Wang Dr. Saburo Hosokawa Prof. Dr. Yoshihisa Sakata Prof. Dr. Tsunehiro Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9906-9909
Photocatalytic conversion of CO2 to reduction products, such as CO, HCOOH, HCHO, CH3OH, and CH4, is one of the most attractive propositions for producing green energy by artificial photosynthesis. Herein, we found that Ga2O3 photocatalysts exhibit high conversion of CO2. Doping of Zn species into Ga2O3 suppresses the H2 evolution derived from overall water splitting and, consequently, Zn‐doped, Ag‐modified Ga2O3 exhibits higher selectivity toward CO evolution than bare, Ag‐modified Ga2O3. We observed stoichiometric amounts of evolved O2 together with CO. Mass spectrometry clarified that the carbon source of the evolved CO is not the residual carbon species on the photocatalyst surface, but the CO2 introduced in the gas phase. Doping of the photocatalyst with Zn is expected to ease the adsorption of CO2 on the catalyst surface. 相似文献
42.
Polycationic‐Shelled Capsular and Tubular Nanostructures and Their Anionic–Guest Binding Properties 下载免费PDF全文
Dr. Kohei Yazaki Dr. Yoshihisa Sei Prof. Dr. Munetaka Akita Dr. Michito Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17557-17561
For the development of novel nanospace with unique electrostatic character, we prepared new capsular and tubular nanostructures by the quantitative assembly of metal ions and bent bisacridinium ligands. The capsule and tube have closed spherical and open cylindrical cavities, respectively, with diameters of around 1 nm surrounded by cationic polyaromatic panels. Thanks to the facile synthetic protocol (three steps), another polycationic capsule with an elliptical nanocavity was also prepared by using an elongated ligand. In spite of the absence of pendant hydrophilic groups, the spherical polyaromatic capsule shows sufficient water solubility due to the polycationic shell. Moreover, the highly cationic cavity (12+) can selectively encapsulate anionic organic compounds in water. 相似文献
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44.
Nobuaki Kitazawa Dhebbajaji Yaemponga Masami Aono Yoshihisa Watanabe 《Journal of luminescence》2009,129(9):1036-1041
Thin films of microcrystalline (C8H17NH3)2PbBr4 have been prepared by the two-step growth process as follows: (1) precipitation of nanometer-sized PbBr2 particles on substrates by vapor deposition and then (2) growth of (C8H17NH3)2PbBr4 films by exposing PbBr2 particles to C8H17NH3Br vapor. Atomic force microscope observations reveal that the substrate is fully covered with nanometer-sized rodlike precipitates. X-ray diffraction studies suggest that (C8H17NH3)2PbBr4 films are found to be microcrystalline form, single phase and highly oriented with the c-axis perpendicular to the substrate surface. (C8H17NH3)2PbBr4 films show a clear exciton absorption and free-exciton emission even at room temperature. At low temperatures below 40 K, the emission band separates into three bands at 3.07 (A-band), 3.14 (B-band) and 3.20 (C-band) eV, respectively. Both A- and C-bands correspond to the free-exciton emission with large binding energies. On the contrary, time-resolved PL spectra indicate that the B-band is attributed to phosphorescence formed by the intersystem crossing. 相似文献
45.
Haino T Araki H Fujiwara Y Tanimoto Y Fukazawa Y 《Chemical communications (Cambridge, England)》2002,(18):2148-2149
A new class of fullerene sensors based on calix[5]arenes has produced the highly sensitive detection of C60 and C70. 相似文献
46.
Kaneda M Asaoka S Ikeda H Mori T Wada T Inoue Y 《Chemical communications (Cambridge, England)》2002,(12):1272-1273
A hydrostatic pressure of up to 750 MPa induced discontinuous changes in the enantiomeric excess of the (E)-isomer obtained in the enantio-differentiating photoisomerization of (Z)-cyclooctene and (Z,Z)-cycloocta-1,5-diene, sensitized by chiral benzene-1,2,4,5-tetracarboxylates; indicating a switching of the enantio-differentiation mechanism, which is attributable to dramatic conformational changes of chiral alkoxycarbonyl auxiliaries at a specific pressure. 相似文献
47.
The stability constant (K), standard free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy changes (T Delta S degrees) for the complexation of 6-amino-6-deoxy-beta-cyclodextrin with more than 50 negatively or positively charged as well as neutral guests, including 22 enantiomer pairs, have been determined in aqueous phosphate buffer (pH 6.9) at 298.15 K by titration microcalorimetry. The thermodynamic parameters obtained in this study and the relevant data for native beta-cyclodextrin indicate that the complexation and chiral discrimination behavior of the cationic host with charged guests are governed by the critical counterbalance between the electrostatic interactions of the charged groups in host and guest and the conventional intracavity interactions of the hydrophobic moiety of guest, such as hydrophobic, van der Waals, solvation/desolvation, and hydrogen-bonding interactions. 相似文献
48.
The memory effect upon glassification is studied in the glass-to-rubber transition of vulcanized rubber with the strain as a controlling parameter. A phenomenological model is proposed, taking the history of the temperature and the strain into account, by which the experimental results are interpreted. The data and the model demonstrate that the glassy state memorizes the time course of strain upon glassification, not as a single parameter but as the history itself. The data also show that the effect of irreversible deformation in the glassy state is beyond the scope of the present model. 相似文献
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50.
The phonon dispersion relations of 00σT branch were measured for Ni95Pt5 and Ni70Pt30. The dispersion curves breaks up into two branches. Th general shape and its concentration dependence can be explained qualitatively by Taylor's coherent potential approximation theory. 相似文献