Porous hybrid Cu2O/polypyrrole nanoflakes have been synthesized from solid CuO nanoplate templates through the pyrrole-induced reductive transformation reaction at elevated temperature. The conversion mechanism involves the reductive transformation of CuO to Cu2O and the in situ oxidative polymerization of pyrrole to polypyrrole. In addition, the morphology of the as-converted nanohybrids depends on the shape of the CuO precursors. The strategy enables us to transform single-crystalline CuO nanosheets into hollow hybrid Cu2O/polypyrrole nanoframes. The ability to transform CuO and an organic monomer into porous hybrid materials of conducting polymer and Cu2O with macrosized morphological retention opens up interesting possibilities to create novel nanostructures. Electrochemical examinations show that these porous hybrid Cu2O/polypyrrole nanostructures exhibit efficient catalytic activity towards oxygen reduction reaction (ORR), excellent methanol tolerance ability, and catalytic stability in alkaline solution, thus making them promising nonprecious-metal-based catalysts for ORR in alkaline fuel cells and metal-air batteries.
High-pressure vaporÀliquid equilibrium data for the binary systems of ethyl butyrate (EB) þ carbon dioxide and propylene carbonate (PC) þ carbon dioxide were measured. The experimental pressure range was from (1.00 to 13.00) MPa and the temperature range from (313.0 to 373.0) K. Experimental results were correlated with the PengÀRobinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry's coefficient and solution enthalpy and solution entropy of CO 2 during dissolution at different temperature were also calculated.
A series of new Pd(II)
complexes with simple structures were designed
and synthesized for Suzuki–Miyaura coupling reactions of aryl
chlorides. The new Pd(II) complexes contain bidentate amine ligands,
and their structures were characterized by single-crystal X-ray diffraction.
They are highly efficient for Suzuki–Miyaura coupling reactions
of aryl chlorides with low catalyst loadings (0.01 mol %) in aqueous
media at room temperature. Two possible reaction pathways involving
a PdII/0/II and a PdII/IV/II catalytic cycle
are proposed, and the mechanism was further investigated using density
functional theory (DFT) calculations.
Engineering two-dimensional (2D) nanosheets into three-dimensional (3D) hierarchical structures is one of the great challenges in nanochemistry and materials science. We report a facile and simple chemical conversion route to fabricate 3D hierarchical nanosheet-based ZnSe microspheres by using 2D inorganic-organic hybrid ZnSe-DETA (DETA = diethylenetriamine) nanosheets as the starting precursors. The conversion mechanism involves the controlled depletion of the organic-component (DETA) from the hybrid precursors and the subsequent self-assembly of the remnant inorganic-component (ZnSe). The transformation reaction of ZnSe-DETA nanosheets is mainly influenced by the concentration of DETA in the reaction solution. We demonstrated that this organic-component depletion method could be extended to the synthesis of other hierarchical structures of metal sulfides. In addition, the obtained hierarchical nanosheet-based ZnSe microspheres exhibited outstanding performance in visible light photocatalytic degradation of methyl orange and were highly active for photocatalytic H2 production.
A pendant drop shape technique, enhanced by video-image digitization, was applied to measure the interfacial tension for n-alkane− water and n-alcohol−water of 6−9 carbon atoms binary systems at the temperature of 293.2 to 343.2 K. The experimental results of interfacial tension measured by this method were correlated for each binary system as a function of temperature. For n-alkane−water binary system, it could be seen from the results that the interfacial tension decreases with increasing temperature. Further, for each n-alkane−water binary system investigated, all data points determined in the present investigation fall approximately on a straight line, that is, the temperature coefficients of the interfacial tension are uniformly negative. For n-alcohol−water binary system, results demonstrate that all γ−T curves present parabolic profiles, that is, the interfacial tension first increases with increasing temperature, then goes through a maximum and eventually decreases with increasing temperature. Moreover, the temperature at which the maximum of the interfacial tension occurs also increases with the number of carbon atoms in the alcoholic molecular chain. The agreement between the values by this method and those from the literature is fairly good.
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