Jiangtian Li

A facile route to synthesize magnetic particles within hollow mesoporous spheres and their performance as separable Hg2+ adsorbents

We present here a simple and effective strategy, called the vacuum nano-casting route (VNR), for fabricating hollow mesoporous spheres with magnetic cores. The loading amount of magnetic cores and saturation magnetization value can be easily tuned by changing the concentration of iron nitrate solution used in the synthesis procedure. After modification with 1,4-bis(triethoxysilyl)propane tetrasulfide (BTESPTS), the composite could be used as a highly selective absorbent of Hg2+, and was conveniently separated by an external magnetic field. The composites are characterized by X-ray diffraction, N2 sorption isotherms, transmission electron microscopy, energy-dispersive spectroscopy, vibrating-sample magnetometry, Fourier-transform infrared spectroscopy and inductively coupled plasma atomic emission spectroscopy.

Electron transport properties of an ethanol-soluble AlQ3-based coordination polymer and its applications in OLED devices

The electronic states (HOMO/LUMO energy levels) and the electron transport characteristics of a novel AlQ3-based coordination polymer recently designed and synthesized are explored by means of cyclic voltammetry and space-charge-limited current measurements. This coordination polymer has high electron mobility, low HOMO/LUMO energy levels, high thermal stability and high solubility in ethanol and therefore can be fabricated into films by a solution process, e.g.spin coating without influencing commonly used emitter layer materials on which the electron transport layer polymer is to be deposited. All these properties and features suggest that this new coordination polymer is a very promising candidate as a high performance and low cost electron transport layer material in the application of organic light-emitting diodes.

A one-pot method to grow pyrochlore H4Nb2O7-octahedron-based photocatalyst

Cubic pyrochlore niobates (A2Nb2O7, Fd-3m) have been shown to exhibit excellent photocatalytic performance and solid niobic acids show great advantages over these niobate photocatalysts. But no pyrochlore niobic acid has been reported. Here we develop a new and one-pot hydrothermal route for high-yield controlled synthesis of pyrochlore H4Nb2O7 with no aid of additives. Combined with the intrinsic loosely pyrochlore structure, the “acidity-promoted effect”, and the high crystallinity, the novel H4Nb2O7 exhibits outstanding photocatalytic activity, i.e., the reaction rate constant of H4Nb2O7 is almost 3 times of that for its amorphous precursor Am–Nb2O5.nH2O, and almost 2 times that of its corresponding calcium pyroniobate. This study discloses insights for the designed strategy of efficient photocatalysts with synergistic features, and this route provides flexibility and selectivity for the deliberate synthesis of other functional materials.

A soluble coordination polymer and its sol–gel-derived amorphous films: synthesis and third-order nonlinear optical properties

A new soluble tris(8-hydroxyquinoline) aluminium (AlQ3)-based coordination polymer named CP-B8QBA-Al has been synthesized. In contrast with the traditional coordination polymers, this new coordination polymer CP-B8QBA-Al does not crystallize and can be fabricated into amorphous films by conventional spin-coating. The third-order nonlinear optical properties of the CP-B8QBA-Al films were investigated using the Z-scan method at 800 nm and 1064 nm, the results show the coordination polymer films have a third-order NLO susceptibility χ(3) value as high as 1.66 × 10−10 esu without nonlinear absorption.

An easy co-casting method to synthesize mesostructured carbon composites with high magnetic separability and acid resistance

Magnetic mesoporous carbon composites with high surface areas and narrow mesopore size distributions were directly replicated from SBA-15 by a simple co-casting method and the amount of incorporated magnetic particles and saturation magnetization value can be easily tuned by changing the added amount of iron source during synthesis. Furthermore, the magnetic mesoporous carbon composites show good acid resistance due to a carbon shell coating structure around the magnetic particles, which is spontaneously formed during the replication process of the mesoporous carbon composites. The characteristics of the as-synthesized magnetic mesoporous carbon composites were examined by X-ray diffraction, N2 sorption, transmission electron microscopy (TEM), Mossbauer spectroscopy and vibrating-sample magnetometry.

Preparation and third-order optical nonlinearity of gold nanoparticles incorporated mesoporous TiO 2 thin films

A kind of Au nanoparticle (NP) containing 2D hexagonal mesoporous TiO2 thin films (MTTFs) has been successfully synthesized through a deposition-precipitation method. The Au NPs show uniform size distribution and the Au content within the MTTFs is measured to be 7.49 wt.%. The third-order nonlinear optical refractive index of the Au NPs contained MTTFs has been measured by the Z-scan technique at 1064 nm. The absolute value of nonlinear refractive index (n2) and third-order nonlinear susceptibility (χ(3)) were calculated to be 2.64×10−7 and 6.32×10−8 esu, respectively. The high nonlinearity of the composite thin films can be attributed to the intraband transition of electrons near the Fermi surface in well-dispersed Au NPs confined in mesoporous channels and the high linear refractive index of the nanocrystalline anatase framework.

Functional significance of N- and C-terminus of the amino acid transporters EAAC1 and ASCT1: characterization of chimeric transporters.

To localize functionally significant domains in the amino acid transporters of mouse brain mEAAC1 and mASCT1, cRNA encoding for wild-type and chimeric transporters was injected into Xenopus oocytes. Activity of expressed transporters was investigated by measurements of uptake of 3H-labeled glutamate and serine and of glutamate- and serine-induced currents under voltage clamp. Though all transporters accept glutamate and serine as substrate, the central part of the protein (Ala94-Met418 of mEAAC1 and Ala119-Ile393 of mASCT1) determines substrate selectivity. The C-terminus rectifies the interaction with the respective substrate. A channel mode of the glutamate transporter can be activated by glutamate and serine, and the N- and C-termini of the mEAAC1 seem to be essential for the channel formation.

Carbon nanostructures formed on mesoporous silica by catalytic chemical vapor deposition of ethene

Three different strategies, wet impregnation, in situ reduction, and grafting with silane coupling agents, have been used to introduce CoNi nanoparticles with different existing forms into mesoporous silica. These composites were used as catalysts to grow nanostructured carbons by catalytic chemical vapor deposition using ethene. Carbon nanotubes (CNTs) with different inner diameters can grow out of mesoporous silica particles incorporated with CoNi nanoclusters. Many fewer CNTs could be found in the pore channels of the sample prepared by using silane coupling agents than in those of the sample synthesized via wet impregnation. No CNTs formed in the pore channels of the sample prepared by in situ reduction. After the removal of silica, different carbon nanostructures have been obtained in the pore channels. Ordered graphite carbon mesostructure was obtained from the sample prepared by in situ reduction. Highly dispersed metal catalysts inside mesopore channels are favorable for the formation of graphite carbons with ordered mesostructures.