Zn(II)-PEG 300 globules as soft template for the synthesis of hexagonal ZnO micronuts by the hydrothermal reaction method.

Hexagonal ZnO micronuts (HZMNs) have been successfully synthesized with the assistance of poly(ethylene glycol) (PEG) 300 via a hydrothermal method. The structure and morphology of the HZMNs were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). An individual ZnO micronut is revealed as twinned crystals. Time-dependent investigation shows that the growth of HZMNs involves a dissolution-recrystallization process followed by Ostwald ripening, in which is the first formed solid ZnO particles dissolve and transform to HZMNs with hollow structure. PEG 300 has been found to play a crucial role in the growth of this unique hollow structure. TEM observations show that the PEG chains aggregate to globules in water, which then have interaction with the dissolved zinc species to form the globules in a coiled state under hydrothermal conditions. These Zn(II)-PEG 300 globules act as soft template for the growth of HZMNs, and the possible growth mechanism is proposed. The room-temperature photoluminescence (PL) spectrum shows red emission around 612 nm with a full width at half-maximum (fwhm) only about 13 nm.

Controlled synthesis of rod-like LiVMoO(6) nanocrystals for application in lithium-ion batteries.

This paper reports a newly developed method for the shape and size control of transition metal composite oxides, such as LiVMoO(6), to obtain significantly enhanced electrode properties for lithium-ion batteries. Rod-like LiVMoO(6) nanocrystals were synthesized through a designed route of partial reduction, self-assembly and re-oxidation. V(5+) and Mo(6+) ions were used with low-grade starting materials to get a mixed valence of V and Mo. It is believed that ion pairs of V(5+)/V(4+) or Mo(6+)/Mo(5+) in the resultant mixture play an important role in the formation of a template precursor by self-assembly during a rheological phase reaction, although further explanation is required. The electrochemical performance of the LiVMoO(6) obtained has been much improved due to the increased crystallinity and reduced particle size of this material. 176 mA h g(-1) and 166 mA h g(-1) capacity was delivered in the initial discharge with a reversible capacity retention of 94.8% and 95.3% after 100 cycles in the range of 3.6-1.80 V versus metallic Li at 1 and 3 C current rate, respectively.

Preparation of SO4(2-)/TiO2-La2O3 solid superacid and its catalytic activities in acetalation and ketalation.

SO(4)(2-)/TiO(2)-La(2)O(3), a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n(La(3+)):n(Ti(4+)) is 1:34, the soaked consistency of H(2)SO(4) is 0.8 mol/L, the soaked time of H(2)SO(4) is 24 h, the calcining temperature is 480 degrees C, the calcining time is 3 h. Then it was applied in the catalytic synthesis of ten important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is 1:1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.

Synthesis of acetals and ketals catalyzed by tungstosilicic acid supported on active carbon.

Catalytic activity of activated carbon supported tungstosilicic acid in synthesizing 2-methyl-2-ethoxycarbonylmethyl- 1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1,2-propa- nediol ketal, butanone ethylene ketal, butanone 1,2-propanediol ketal, 2-phenyl-1,3-dioxolane, 4-methyl-2-phenyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 4-methyl-2-propyl-1,3-dioxolane was reported. It has been demonstrated that activated carbon supported tungstosilicic acid is an excellent catalyst. Various factors involved in these reactions were investigated. The optimum conditions found were: molar ratio of aldehyde/ketone to glycol is 1/1.5, mass ratio of the catalyst used to the reactants is 1.0%, and reaction time is 1.0 h. Under these conditions, the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 61.5%, of 2,4-dimethyl- 2-ethoxycarbonylmethyl-1,3-dioxolane is 69.1%, of cyclohexanone ethylene ketal is 74.6%, of cyclohexanone 1,2-propanediol ketal is 80.1%, of butanone ethylene ketal is 69.5%, of butanone 1,2-propanediol ketal is 78.5%, of 2-phenyl-1,3-dioxolane is 56.7%, of 4-methyl-2-phenyl-1,3-dioxolane is 86.2%, of 2-propyl-1,3-dioxolane is 87.5%, of 4-methyl-2-propyl-1,3-dioxolane is 87.9%.

[Rheological phase synthesis and characterization of lanthanum salicylate and luminescence properties of Tb3+ -doped lanthanum salicylate].

Lanthanum salicylate and Tb3+ -doped lanthanum salicylate were synthesized with the rheological phase reaction method. Elemental analysis, IR, TG, DTA and powder X-ray diffraction were investigated to determine the composition, crystal structure and coordination manner between the COO- and ion La3+ of lanthanum salicylate. The emission and excitation spectra of Tb3+ -doped lanthanum salicylate were also discussed. Powder X-ray diffraction suggests that the compound has a layered monoclinic structure, and the lattice parameters are a = 21.6010 A, b = 13.8015 A , c = 3.8103 A, beta = 97.11 degrees, V = 1127.2 A3, Z = 2, rhocal = 1.621 g x cm(-3) and rhoexp = 1.653 g x cm(-3). The Tb3+ -doped lanthanum salicylate exhibits very strong green luminescence of Tb3+ under the excitation of UV light. And the transition from 5D4 to 7F5 is the strongest one.

[Catalytic application of synthesizing n-butyl acrylate by a new type nanometer complex heteropoly acid catalyst H3PW12O40/SiO2].

A new nanometer complex heteropoly acid with Keggin structure, H3PW12O40/SiO2, were prepared by sol-gel method, and were characterized with IR, UV, XRD and TEM techniques. By means of this nanometer catalytic materials, the optimum conditions of the n-butyl acrylate synthesis have been studied. The results show that the complex heteropoly acid H3PW12O40/SiO2 nanoparticles have the mean grain size of 40 nm and they are typical amorphous. A strong chemical interaction exists between H3PW12O40 and silica surface. The nanoparticles have high catalytic activity for synthesizing n-butyl acrylate. The optimum catalytic conditions are as follows: the mole ratio of acrylic acid and n-butyl alcohol is 1:1.2, the reaction temperature is approximately 90-96 degrees C, and the catalyst quantity in the reaction is 10% of the acid mass. The conversion proportion is 94.37% and product yield 91.2% in 5 h. Apparently, the unique structure of the Keggin anions and surface acid center and the high specific surface area and the pseudoliquid phase of H3PW12O40/SiO2 play an important role in the esterification reactions with the acid catalyst.

Synthesis and luminescence of zinc and europium alpha-thiophene carboxylate polymer.

The zinc and europium alpha-thiophene carboxylate polymer with very strong red luminescence was prepared by rheological phase reaction method from zinc acetate, europium oxide and alpha-thiophenecarboxylic acid. Molecular weight, thermal analyses and X-ray diffraction pattern were measured. 1H NMR, 13C NMR, IR, XPS, UV, excitation and emission spectra were studied. The polymer with amorphous structure and 7.565x10(5) g/mol weight-average molecular exhibited excellent solubility in common organic solvents and better thermal stability under 270 degrees C in air. The quantum yield of the polymer in acetone was 0.6 relative to quinoline in 0.05 mol/l H(2)SO(4) solution. The energy of the pi,pi(*) excited state of C(4)H(3)SCO(2)(-) can be transferred to Eu(3+) ion resulting in emission from the 5D(0)-->(7)F(j) of Eu(3+) ion through the polymeric chains. Zn(2+) can effectively enhance the luminescence of Eu(3+) in alpha-thiophenecarboxylate polymer.

[Research on IR spectra of Li-Mn spinel].

The infrared spectra of Li-Mn-spinel were studied in this paper. As the structure of Li-Mn-spinel was classified as Fd3m space group, the lithium ions (Li(I)) occupy tetrahedral sites (8a sites) and manganese ions (Mn(IV) or Mn(III)) occupy octahedral sites (16d sites). The internal relationship between vibration modes and infrared activity was discussed based on the knowledge of group theory. The experimental IR spectra of Li-Mn-spinel were presented also. By theoretical analysis, we concluded that the bands at 618.6 and 501.5 cm-1 resulted from anti-symmetric stretching vibration of Mn(IV)-O and Mn (III)-O in Li-Mn-spinel crystal (Mn(IV)O6 and Mn(III)O6 octahedron), respectively, the weak band at 1,124 cm-1 resulted from anti-symmetric stretching vibration of Li-O in the spinel (LiO4 tetrahedron), and other possible bands at wave number lower than 400 cm-1 were not detected in the range from 400 to 4,000 cm-1. The reliability of conclusions was proved by IR spectra of both the Li-Mn-spinel and doped Li-Mn-spinel.

Luminescence of Tb3+ and Eu3+ doped amorphous zinc benzoates.

The Tb(3+) and Eu(3+) doped amorphous zinc benzoate were prepared. Their infrared absorption, emission and excitation spectra were measured. The luminescence mechanisms of Tb(3+) and Eu(3+) in the amorphous substrate were discussed. The bonding modes of OCO group to Zn(2+) ion have two of symmetric and asymmetric bridging bidentate. The energy of the S(1) pi,pi* excited state of benzene ring can be transferred to Tb(3+) and Eu(3+) ion, and results in characteristic emission from the 5D(4)-->(7)F(j) of Tb(3+) and 5D(0)-->(7)F(j) of Eu(3+), respectively.