Li-Na Jin

Shape-controlled synthesis of Co3O4 nanostructures derived from coordination polymer precursors and their application to the thermal decomposition of ammonium perchlorate

In this paper, we report a facile approach for the shape-controlled synthesis of cobalt(II)-based coordination polymer particles. Three different structures of flower-like architectures, multilayer stacked structures and nanosheets have been synthesized by varying the volume ratio of ethanol and water. Phase-pure Co3O4 nanocrystals have been obtained by annealing the coordination polymer particles without significant alterations in morphology. The products have been characterized by X-ray diffraction techniques, field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The catalytic effect was investigated for the Co3O4 nanocrystals with different morphology on the thermal decomposition of ammonium perchlorate (AP) and it was found that the Co3O4 nanosheet has the highest catalytic activity. The surface areas of Co3O4 nanocrystals are measured by the Brunauer–Emmett–Teller (BET) technique and the results show that the catalytic activity of Co3O4 nanocrystals for the thermal decomposition of AP increases with the increase of BET surface area and pore volume.

Large-scale preparation of indium-based infinite coordination polymer hierarchical nanostructures and their good capability for water treatment.

The removal of dyes in wastewater has been of much interest in the recent decades because dyes are stable, toxic and even potentially carcinogenic, and their release into environment causes serious environmental, aesthetical, and health problems. In the current work, indium-based coordination polymer particles (In-CPPs) have been fabricated via a facile solvothermal synthesis without any template or surfactant. In-CPPs are composed of hierarchical nanostructures assembled from abundant nanoplates with thickness of about 20 nm. Owing to their high BET surface area and pore volume, In-CPPs exhibit excellent adsorption capability for Congo red with a maximum capacity of 577 mg g(-1), which was higher than that of most materials reported to now. In-CPPS can also be outstanding adsorbents for removing other dyes such as acid chrome blue K, brilliant red GR and brilliant green. Furthermore, after calcinations in air In-CPPs can be converted to morphology-preserved porous In2O3 products which can detect NOx gas in air at room temperature.

Size-controlled indium(III)–benzenedicarboxylate hexagonal rods and their transformation to In2O3 hollow structures

Size-controlled In2O3 hollow structures have been successfully prepared by a two-step process. Indium(III)–benzenedicarboxylate (In–BDC) hexagonal rods with different sizes were first obtained on a large scale via a simple solution reaction using indium(III) nitrate and 1,4-benzenedicarboxylic acid as starting reactants and DMF as solvent with addition of sodium acetate. Then In2O3 hollow structures were prepared by annealing In–BDC complexes. It was found that the concentration of sodium acetate is important in determining the size of In–BDC hexagonal rods as well as the formation of In2O3 hollow structures. The products were characterized by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). In addition, In2O3 hollow structures were further studied by Raman and room-temperature photoluminescence.

Ultrasonic-assisted solution-phase synthesis of gadolinium benzene-1,4-dicarboxylate hierarchical architectures and their solid-state thermal transformation

Well-dispersed hierarchical straw–sheaf-like architectures of [Gd(1,4-BDC)1.5(H2O)2] (BDC2− = benzene-1,4-dicarboxylate) have been successfully synthesized via an ultrasonic-assisted solution-phase method in the presence of polyvinylpyrrolidone (PVP, 30 K). The as-obtained products were characterized by X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Systematic investigations have been performed on the factors influencing the morphology of [Gd(1,4-BDC)1.5(H2O)2] nanostructures, such as the concentration of Na2BDC and Gd(NO3)3·6H2O, the ultrasonic time and power, as well as the amount of PVP. A possible mechanism responsible for the formation of hierarchical architectures was proposed. The as-obtained Eu3+- and Tb3+-doped [Gd(1,4-BDC)1.5(H2O)2] products show strong characteristic red and green emissions under ultraviolet excitation. Furthermore, the straw–sheaf shaped Gd2O3 can be obtained via a thermal decomposition method using the Gd-1,4-BDC complex as a precursor.

Coordination modulation induced and ultrasonic-assisted synthesis of size-controlled microporous metal–imidazolate framework crystals with enhanced adsorption performance

Size-controlled metal–imidazolate framework crystals have been synthesized by combining the coordination modulation method and ultrasonic-assisted synthesis for the first time. Aqueous ammonia was used as the coordination modulator, and was found to be able to control the crystal size. The as-obtained crystals had improved adsorption properties compared with that of the bulk ones.

Metal ion induced porous HKUST-1 nano/microcrystals with controllable morphology and size

Porous coordination polymer HKUST-1 [Cu3(BTC)2] (H3BTC = 1,3,5-benzenetricarbocylic acid) nano/microcrystals have been fabricated by an environment friendly facile direct precipitation method at room temperature using inorganic salts such as NaNO3, NaCl, NaBr, KNO3, KCl and KBr as additives. It is found that the concentration of the inorganic salt has an important impact on the morphology and size of the HKUST-1 crystals, and their morphology changed from cube to cuboctahedron and finally to octahedron by increasing the concentration of inorganic salts. Gas adsorption measurements reveal that HKUST-1 nano/microcrystals with different morphologies show high specific surface areas, and their gas sorption properties depend on the crystal morphology and size.