Zhengzhou, China
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Xue B.Y.,Henan Academy of science | Dillon K.B.,Durham University
Helvetica Chimica Acta | Year: 2013

Variation in the position of CF3 groups in several aromatic Group-14 compounds was studied by 19F-NMR spectroscopy. In these compounds RnECl4-n (n=1 or 2; E=Si, Ge, or Sn; R=2,4,6-(CF3)3C6H2 (=Ar), 2,6-(CF3)2C6H3 (=Ar′), or 2,4-(CF3)2C6H3 (=Ar″)), Ar, Ar′, and Ar″ are all bulky, strongly electron-withdrawing ligands. The 19F-NMR studies of the variation in position of the CF 3 substituents in these compounds as revealed by chemical shifts could be correlated with the electronegativities of the central elements E, and with intramolecular E-F interactions derived from single-crystal X-ray diffraction data. These interactions are considered to play an important role in the stabilization of these compounds. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Tang X.,Xiamen University | Zeng X.,Xiamen University | Li Z.,Xiamen University | Hu L.,Huaiyin Normal University | And 4 more authors.
Renewable and Sustainable Energy Reviews | Year: 2014

Recently, valorization of lignocellulosic biomass, the most abundantly available biomass raw material on the Earth, to biofuels and chemicals has attracted great attention worldwide for the purpose of reducing our overwhelming reliance on the non-renewable petroleum resources. γ-Valerolactone (GVL) has recently been hailed as a versatile building block which can be derived from renewable lignocellulosic biomass resource for energy, chemical and material sectors. In this review, focus was principally put on the applications of GVL as a renewable carbon source for green solvents and transportation fuels. In addition, advances in the GVL production through selective reduction of commercial or biomass-derived levulinic acid (LA) and its esters using various hydrogen sources, mainly including molecule H2, formic acid (FA) and alcohols, have been carefully summarized. Moreover, assessment of the relative merits of different hydrogen sources for the GVL production has also been performed. © 2014 Elsevier Ltd.

Li C.,Zhengzhou University of Light Industry | Li C.,Henan Academy of Science | Wei W.,Zhengzhou University of Light Industry | Fang S.,Zhengzhou University of Light Industry | And 4 more authors.
Journal of Power Sources | Year: 2010

A novel CuO-nanotubes/SnO2 composite was prepared by a facile solution method and its electrochemical properties were investigated as the anode material for Li-ion battery. The as-prepared composite consisted of monoclinic-phase CuO-nanotubes and cassiterite structure SnO2 nanoparticles, in which SnO2 nanoparticles were dramatically decorated on the CuO-nanotubes. The composite showed higher reversible capacity, better durability and high rate performance than the pure SnO2. The better electrochemical performance could be attributed to the introducing of the CuO-nanotubes. It was found that the CuO-nanotubes were reduced to metallic Cu in the first discharge cycle, which can retain tube structure of the CuO-nanotubes as a tube buffer to alleviate the volume expansion of SnO2 during cycling and act as a good conductor to improve the electrical conductivity of the electrodes. © 2009 Elsevier B.V. All rights reserved.

Duan J.,Tianjin Institute of Urban Construction | Liu R.,Zhengzhou University | Chen T.,Henan Academy of science | Zhang B.,Zhengzhou University | Liu J.,Zhengzhou University
Desalination | Year: 2012

The magnetic composite of Fe 3O 4-halloysite nanotube (HNT) was prepared by chemical precipitation method. The prepared adsorbents were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and multipoint Brunauer-Emmett-Teller (MBET). The results revealed that Fe 3O 4 particles with diameter of 3-5nm dispersed on the nanotube surface and formed a composite with halloysite. The Fe 3O 4-HNTs composite exhibited fine magnetic property (Ms=8.47emu/g) and could be easily separated from aqueous solution by the application of an external magnetic field. Adsorption results showed that Fe 3O 4-HNTs composite could maintain a high adsorption capacity for methyl violet (MV) when the pH, concentration of metal ion and temperature varied. Adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data fitted well with the Langmuir isotherm. The used Fe 3O 4-HNTs could be regenerated by simple calcinations. The recovered adsorbents could be used again for MV removal and magnetic separation. Because of the excellent adsorption capacity at different conditions, reproducibility and separability, Fe 3O 4-HNTs composite is a promising candidate for removing cationic dye from waste water. © 2012 Elsevier B.V.

Wei M.-L.,Henan Normal University | Sun J.-J.,Henan Normal University | Duan X.-Y.,Henan Academy of science
European Journal of Inorganic Chemistry | Year: 2014

A metal-Schiff-base-POM-MOF, {[Cu3(L)2(H 2O)4] [Cu(dmf)4(SiW12O 40)]·9H2O}n {L = N,N-bis[(2-hydroxy-3- methoxyphenyl)methylidene]hydrazine hydrate}, has been synthesized in situ from [SiW12O40]4-, Cu2+ and L in an H2O/dmf/CH3OH/CH3CN mixture at room temperature, and the product was characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction analysis. X-ray diffraction analysis revealed that the title complex presents a 3D network constructed from CuII-Schiff-base cations, 1D POM-MOF chains and solvent water molecules. Its water vapour adsorption isotherm at room temperature and pressure shows that the water vapour adsorbed by the complex is 51.67 cm3 g-1 at the maximum allowable humidity, which corresponds to 7.1 water molecules per unit formula. In addition, it exhibits good proton conductivity (>10-4 S cm-1) at 100 °C in the relative humidity range 35-98 %. The corresponding activation energy (Ea) of conductivity was estimated to be 0.32 eV. A 3D metal-Schiff-base-POM-MOF has been constructed by combining in situ two traditional building blocks, a metal-Schiff-base and POM-MOF, and its structure was determined by single-crystal X-ray diffraction. Due to the bonding of H2O to otherwise open coordination sites on Cu2+ ions, it shows good proton conductivities of 10-5-10-4 S cm-1 in the temperature range of 25-100 °C under 98 % RH. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wei M.,Henan Normal University | Wang X.,Henan Normal University | Duan X.,Henan Academy of science
Chemistry - A European Journal | Year: 2013

We have succeeded in constructing a metal-organic framework (MOF), [Cu(bpdc)(H2O)2]n (H2bpdc=2, 2′-bipyridyl-3,3′-dicarboxylic acid, 1), and two poly-POM-MOFs (POM=polyoxometalate), {H[Cu(Hbpdc)(H2O)2] 2[PM12O40]·n H2O}n (M=Mo for 2, W for 3), by the controllable self-assembly of H2bpdc, Keggin-anions, and Cu2+ ions based on electrostatic and coordination interactions. Notably, these three compounds all crystallized in the monoclinic space group P21/n, and the Hbpdc- and bpdc2- ions have the same coordination mode. Interestingly, in compounds 2 and 3, Hbpdc- and the Keggin-anion are covalently linked to the transition metal copper at the same time as polydentate organic ligand and as polydentate inorganic ligand, respectively. Complexes 2 and 3 represent new and rare examples of introducing the metal N-heterocyclic multi-carboxylic acid frameworks into POMs, thereby, opening a pathway for the design and the synthesis of multifunctional hybrid materials based on two building units. The Keggin-anions being immobilized as part of the metal N-heterocyclic multi-carboxylic acid frameworks not only enhance the thermal stability of compounds 2 and 3, but also introduce functionality inside their structures, thereby, realizing four approaches in the 1D hydrophilic channel used to engender proton conductivity in MOFs for the first time. Complexes 2 and 3 exhibit good proton conductivity (10-4 to ca. 10-3 S cm-1) at 100 °C in the relative humidity range 35 to about 98 %. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wei M.,Henan Normal University | Wang X.,Henan Normal University | Sun J.,Henan Normal University | Duan X.,Henan Academy of science
Journal of Solid State Chemistry | Year: 2013

We have succeeded in constructing a 3D POM-MOF, {H[Ni(Hbpdc)(H 2O)2]2[PW12O40] ·8H2O}n (H2bpdc=2,2′-bipyridyl-3, 3′-dicarboxylic acid), by the controllable self-assembly of H 2bpdc, Keggin-anions and Ni2+ ions based on the electrostatic and coordination interactions. Interestingly, Hbpdc- as polydentate organic ligands and Keggin-anion as polydentate inorganic ligands are covalently linked transition-metal nickel at the same time. The title complex represents a new example of introducing the metal N-heterocyclic multi-carboxylic acid frameworks into POMs chemistry. Based on Keggin-anions being immobilized as part of the metal N-heterocyclic multi-carboxylic acid framework, the title complex realizes four approaches in the 1D hydrophilic channel used to engender proton conductivity in MOFs. Its water adsorption isotherm at room temperature and pressure shows that the water content in it was 31 cm3 g-1 at the maximum allowable humidity, corresponding to 3.7 water molecules per unit formula. It exhibits good proton conductivities (10-4-10-3 S cm-1) at 100 C in the relative humidity range 35-98%. The corresponding activation energy (E a) of conductivity was estimated to be 1.01 eV. © 2013 Elsevier Inc.

Wang J.,Henan Academy of science | Wang J.,HIGH-TECH | Zhang K.,Zhengzhou University | Zhao L.,Henan Academy of science | Zhao L.,HIGH-TECH
Chemical Engineering Journal | Year: 2014

Polyaniline (PANI) nanoparticles and 1D nanostructures were prepared by a facile sono-assisted chemical oxidation method in protonic acids like HCl, surfulamic acid (SA), citric acid (CA), taurine (TA) and neutral deionized (DI) water for removal of aqueous Cr(VI). Results showed that all the prepared PANI nanostructures showed efficient adsorption for Cr(VI), however, their adsorption efficiencies varied depending on the protonic acids and the consequent molecular structures of PANIs. Among them, the PANI-HCl prepared in strong HCl acid showed the highest adsorption capacity, followed in descending order by PANI-SA, PANI-CA, PANI-TA and PANI-DI. The adsorption capacity was correlated well with oxidation state and protonation extent of PANIs. Solution pH had an obvious effect on Cr(VI) adsorption, especially for PANI-TA and PANI-DI. A mechanism of electrostatic adsorption followed by reduction of Cr(VI) to Cr(III) was proposed by analyzing FTIR, zeta potential and XPS spectra of PANIs before and after Cr(VI) adsorption. © 2013 Elsevier B.V.

Zhao Y.,Zhengzhou University | Zhang B.,Zhengzhou University | Zhang B.,Henan Academy of science | Zhang X.,Zhengzhou University | And 3 more authors.
Journal of Hazardous Materials | Year: 2010

Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH4 +) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH4 + concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3mgg-1 of NH4 + was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH4 + removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH4 + pollutants from wastewaters. © 2010 Elsevier B.V.

Gao A.,Zhengzhou University | Gao A.,Henan Academy of science | Yang F.,Zhengzhou University | Li J.,Henan Academy of science | Wu Y.,Zhengzhou University
Tetrahedron | Year: 2012

A facile and practical method for the palladium/copper-catalyzed transformation of internal alkynes into 1,2-diketones has been described, affording the desired products in moderate to excellent yields. The mechanistic studies were also preliminarily pursued using diphenyl sulfoxide as the oxidant, and the diphenyl sulfide was isolated as the reduced product. © 2012 Elsevier Ltd. All rights reserved.

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