Facile Precipitation Route Research Articles

Trisodium citrate assisted synthesis of ZnO hollow spheres via a facile precipitation route and their application as gas sensor

To enrich the variety of zinc oxide, a facile trisodium citrate assisted alkaline precipitation route was developed to prepare ZnO hollow spheres with partial open gaps comprised of a mass of nanoparticles. The composition, morphology and structure of the product were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the final products were pure hexagonal phase (zincite), and the ZnO shell was composed of a polycrystalline aggregation of nanoparticles. Trisodium citrate played a crucial role as a capping agent in the formation of the ZnO hollow spheres. The ZnO with hollow morphology exhibited excellent gas response. This result indicated that the annealed ZnO with hollow sphere architecture is a promising candidate for gas sensing applications.

Self-Assembled Microfibers of Simple Amphiphilic Molecules Through a Facile Precipitation Route

One-dimensional (1D) fiber structures of simple amphiphilic molecules were prepared through a facile precipitation route. The self-assembly process was studied by ultraviolet-visible absorption and Fourier transform infrared) spectroscopy, which indicated that hydrogen bonding interactions played a role in the1D growth along the axis of the fiber. The water content, self-assembling temperature, and concentration of 1,5-bis-(1-(pyridin-2-yl)ethylidene)thiocarbonohydrazide molecules in the solution had obvious effects on the size and morphology of the self-assembled products. The formation of1D superstructures is not only of a hot subject in the process of nanoscience but also opens a new venue for conveniently controlling self-assembled structures of similar organic molecules.

Eu3+/Tb3+-Doped La2O2CO3/La2O3 Nano/Microcrystals with Multiform Morphologies: Facile Synthesis, Growth Mechanism, and Luminescence Properties

LaCO(3)OH nano/microcrystals with a variety of morphologies/sizes including nanoflakes, microflowers, nano/microrhombuses, two-double microhexagrams sandwichlike microspindles, and peach-nucleus-shaped microcrystals have been synthesized via a facile homogeneous precipitation route under mild conditions. A series of controlled experiments indicate that the pH values in the initial reaction systems, carbon sources, and simple ions (NH(4)(+) and Na(+)) were responsible for the shape determination of the LaCO(3)OH products. A possible formation mechanism for these products with diverse architectures has been presented. After annealing at suitable temperatures, LaCO(3)OH was easily converted to La(2)O(2)CO(3) and La(2)O(3) with the initial morphologies. A systematic study on the photoluminescence and cathodoluminescence properties of Eu(3+)- or Tb(3+)-doped La(2)O(2)CO(3)/La(2)O(3) samples has been performed in detail. The excitation and site-selective emission spectra were recorded to investigate the microstructure, site symmetry, and difference in the (5)D(0) → (7)F(2) transition of Eu(3+) ions in La(2)O(2)CO(3) and La(2)O(3) host lattices. In addition, the dependence of the luminescent intensity on the morphology for the as-prepared La(2)O(2)CO(3)/La(2)O(3):Ln(3+) (Ln = Eu, Tb) samples has been investigated. The ability of generating diverse morphologies and multiemitting colors for different rare-earth activator ion (Ln = Eu, Tb) doped La(2)O(2)CO(3)/La(2)O(3) nano/microstructures provides a great opportunity for the systematic evaluation of morphology-dependent luminescence properties, as well as the full exploration of their application in many types of color display fields.

Fe 2O 3 core–NaCo[Fe(CN) 6] shell nanoparticles—Synthesis and characterization

A facile precipitation route was developed for the synthesis of cobalt hexacyanoferrate (CoHCF) as a thin shell around cores of nanoparticles of iron(III) oxide, forming nanoparticles of iron(III) oxide@CoHCF (n-Fe 2O 3@NaCo[Fe(CN) 6]). The morphology and structure of the as-prepared n-Fe 2O 3@NaCo[Fe(CN) 6] were characterized by the techniques of electron microscopies, X-ray diffraction measurements, X-ray photoelectron spectroscopy, infrared spectroscopy and thermogravimetry. Carbon composite electrodes of n-Fe 2O 3@NaCo[Fe(CN) 6] were prepared and the electrochemical behavior of the nanoparticles was evaluated using cyclic voltammetry. The redox couples of n-Fe 2O 3@NaCo[Fe(CN) 6] were investigated and the diffusion coefficients of counter cation in the shell of CoHCF were obtained. The effect of size of particles and the structure of CoHCF was also evaluated. n-Fe 2O 3@NaCo[Fe(CN) 6] represented prominent electrocatalytic activity toward the oxidation of some biologically active compounds.