Feng Cao

One-pot synthesis of flowerlike Ni7S6 and its application in selective hydrogenation of chloronitrobenzene

Uniform flowerlike Ni7S6 nanostructures composed of nanopetals with sharp tips have been synthesized by a mild hydrothermal method. On the basis of a series of contrast experiments, a probable growth mechanism and fabrication process of the flowerlike products was proposed. The catalytic performances of the as-synthesized samples were tested in selective hydrogenation of chloronitrobezene. Compared with other nickel sulfide samples with different morphologies and structures, flowerlike Ni7S6 samples show much higher activity and selectivity in the hydrogenations of nitrobenzene and chloronitrobenzenes with different chlorine substituent site. To the best of our knowledge, this is the first time that uniform flower-like Ni7S6 with high selectivity to nitro group have been synthesized in solution.

Bi2Te3 nanoplates and nanoflowers: Synthesized by hydrothermal process and their enhanced thermoelectric properties

Bi2Te3 nanoplates with a thickness of 15–20 nm and self-assembled flower-like nanostructures using previous nanoplates as building blocks have been fabricated through a low-cost hydrothermal method with ethylenediamine tetraacetic acid (EDTA) as an additive. The structures and morphologies of the samples were characterized viaX-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FT-IR) and transmission electron microscope (TEM) measurements. The growth mechanisms have been proposed based on the experimental results. The nanoplates and flower-like Bi2Te3 nanocrystals (NCs) with no residual additives were consolidated by high pressure to an n-type nanostructured bulk material with preserved crystal grain sizes. Moreover, self-assembly NCs show higher thermoelectric properties than the nanoplates. The power factors and thermoelectric figure of merit (ZT) of chemically synthesized flower-like Bi2Te3 NCs were improved up to 8.6 μW cm−1K−2 and 0.7, respectively, which possess the potential to design new materials and devices for thermoelectric applications.

Porous Co3O4 microcubes: hydrothermal synthesis, catalytic and magnetic properties

Well-defined porous Co3O4 microcubes have been synthesized by a simple one-pot solvothermal method combined with subsequent calcination. The formation mechanism of the cube-like precursor was proposed based on the anisotropic intrinsic structure of CoCO3. Importantly, after thermal treatment, the cube-like morphology could be completely preserved. Moreover, the thermal decomposition of the corresponding precursor led to the formation of porous structure. The effects of calcination temperature on the catalytic properties of Co3O4 samples were investigated and the results demonstrated that 600 °C was superior among three samples with the highest catalytic properties. Additionally, as an antiferromagnetic material, the sample showed a certain degree of ferromagnetism under the external magnetic field.

Tetracarboxylate-based Co(II), Ni(II) and Cu(II) three-dimensional coordination polymers: syntheses, structures and magnetic properties

Methylenediisophthalic acid (H(4)MDIP), as semi-rigid V-shaped carboxylate ligands, react with CoO, NiO and Cu(NO(3))(2)·3H(2)O to give three novel coordination polymers [H(3)O](2)[Co(3)(MDIP)(2)]·2DMF (1), [Ni(2)(HMDIP)(μ(2)-OH)(H(2)O)(3)(DMF)]·4H(2)O·DMF (2) and [Cu(3)(MDIP)(μ(2)-OH)(2)(H(2)O)(4)]·6.5H(2)O (3) (DMF = N,N-dimethylformamide). All compounds have been characterized by thermogravimetric analysis, IR spectroscopy, elemental and single-crystal X-ray diffraction analyses. Complex 1 is an unusual open anionic framework that is defined as the metal-organic replica of fluorite. Both 2 and 3 features a 3D open framework with one-dimensional elliptical channels and R- and L-helical chains, and their resulting frameworks can be rationalized as crb and pts topology respectively. An interesting feature of complex 3 is the presence of the linear Cu(3) units that is formed by carboxylate and μ(2)-hydroxyl groups linking three Cu(II) metal centers. Magnetic investigations indicate that ferromagnetic couplings are dominant in the three compounds.

Surfactant-free preparation of NiO nanoflowers and their lithium storage properties

Well-defined 3D Ni(OH)2 nanoflowers were synthesized in high yield via a simple surfactant-free hydrothermal process. On the basis of a series of contrast experiments, the probable growth mechanism and fabrication process of the products were proposed. NiO nanoflowers have also been obtained by thermal decomposition of Ni(OH)2 nanoflowers in air at 500 °C. N2 adsorption–desorption measurements indicate the BET surface area is 198 m2 g−1 and the average pore size of the NiO nanoflowers is 15.1 nm. The electrochemical properties of the NiO electrodes in a lithium ion battery and magnetic performance were also investigated. The first discharge capacity of the NiO nanoflowers could reach about 1300 mA h g−1. The unique flower-like structure played a critical role in the morphology requirement to serve as a transport path for lithium ions in lithium batteries.

Five three/two-fold interpenetrating architectures from self-assembly of fluorene-2,7-dicarboxylic acid derivatives and d10 metals

Five new three/two-fold interpenetrated coordination polymers, namely, [Cd(mfda)(L1)] (1), [Cd(efda)(L1)] (2), [Zn2(mfda)2(L2)]·DMF·H2O (3), [Zn2(efda)2(L2)]·(DMF)0.25, (4) and [Cd2(mfda)2(L2)2]·DMF·H2O (5) (H2mfda = 9,9-dimethylfluorene-2,7-dicarboxylic acid, H2efda = 9,9-diethylfluorene-2,7-dicarboxylic acid, L1 = Methylene bis(3,5-dimethylpyrazole) and L2 = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), have been synthesized under solvent-thermal conditions with mixed ligands. Compounds 1 and 2 are isostructural and possess two-dimensional (6, 3) layered structures containing two kinds of rings. Three equivalent (6, 3) net interpenetrate in a parallel fashion to form an unprecedented mat-like 2D sheet. Compounds 3 and 4 are almost identical in structure and display threefold interpenetrating α–Po net structures. Compound 5 displays a twofold interpenetrated 3D 6-connected net with α–Po topology. The luminescent properties of these compounds have been studied in the solid state at room temperature.

Hydrothermal synthesis and upconversion photoluminescence properties of lanthanide doped YF3 sub-microflowers

Yttrium fluoride sub-microflowers were synthesized by facile hydrothermal route without using any expensive or environmental unfriendly agents. The influences of various hydrothermal parameters on the final products were investigated. It was found that the concentration of NH3·H2O had a significant effect on the morphology change of YF3 sub-microcrystals. The growth mechanism of the as-obtained YF3 sub-microflowers was proposed. The multicolor upconversion (UC) photoluminescence (PL) was successfully realized in Yb3+/Tm3+, Yb3+/Ho3+ and Yb3+/Er3+ doped YF3 sub-microflowers when excited by 980 nm laser diode (LD). The pumping power dependence of the fluorescent intensity is investigated to understand the fundamental UC mechanism.

Fabrication of fluorescent silica-Au hybrid nanostructures for targeted imaging of tumor cells.

Uniform core-satellite structured nanoparticles containing organic dye incorporated in the silica shell and fluorescence quenching Au nanoparticles have been synthesized with excellent fluorescent properties, and their targeted imaging application in tumor cells has been investigated.

Cobalt and nickel with various morphologies: mineralizer-assisted synthesis, formation mechanism, and magnetic properties

Uniform Ni microflowers and Co microspheres have been synthesized by a simple one-pot hydrothermal method with high yield. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and superconducting quantum interference device (SQUID). The synthesis of various shaped nanomaterials was achieved using different alkali metal salts. This is the first report on synthesizing Ni and Co nanostructures using different mineralization to modulate the morphology of the final products. In addition, these synthesized Ni and Co nanocrystals exhibit room-temperature enhanced magnetic properties. Such a facile one-pot approach may also be applied for the synthesis of other metal materials.