Morphology Of As-synthesized Products Research Articles

Hydrothermal synthesis of urchin-like MnO2 nanostructures and its electrochemical character for supercapacitor

Urchin-like α-MnO2 nanostructures were successfully synthesized via a simple hydrothermal process at different synthesis temperatures without using any template or surfactant. The microstructure and morphology of as-synthesized products were systematically investigated by focused ion beam, transmission electron microscopy, and high-resolution transmission electron microscopy. The electrochemical test of the prepared MnO2 exhibits ideal cyclic voltammetry behavior, high specific capacitance (151.5Fg−1 at a current density of 1Ag−1) and excellent cycling stability (93.4% capacitance retention after 1000 cycles) which suggests its promising application as supercapacitor.

Synthesis, characterization, optical and magnetic properties of a nickel sulfide series by three different methods

Two methods of thermal decomposition and hydrothermal routes were applied for synthesis of nickel sulfides of new precursor [Ni(TSC)2]Cl2 (TSC=thiosemicarbazide) and compared two methods with each other. Also another method by direct putting a mixed aqueous solution composed of NiCl2⋅6H2O and TSC (H2NNHCSNH2) into an autoclave without presence of any surfactants was examined to investigate the morphology of products. The effect of the reaction temperature on phase and morphology of as-synthesized products was investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), ultraviolet–visible spectroscopy (UV–Vis) and photoluminescence spectroscopy (PL). Magnetization measurement indicates that NiS samples show a weak ferromagnetic behavior maybe due to nano-size effect.

Synthesis of SnO2 Nanostructures and Their Application for Hydrogen Evolution Reaction

SnO2 hierarchical architectures were synthesized with a surfactant-free hydrothermal synthesis route. We found that the acid or alkaline amount (HCl or NaOH) of the solution had a remarkable effect on the morphology of as-synthesized products. The SnO2 nanostructures were selected as a support of Pt catalyst (Pt/SnO2) for hydrogen evolution reaction (HER) in the acidic media. The influence of SnO2 morphologies on the electrochemical performance has been investigated by cyclic voltammetry and linear sweeping voltammetry using the rotating disk electrodes. In addition, the effect on the catalytic activity in different electrolyte concentration was taken into account. Kinetic study shows that the HER on the Pt/SnO2(flower) electrocatalyst gives a higher exchange current density and a lower overpotential in H2SO4 solution with high concentration. Tunable synthesis of SnO2nanostructures has been achieved via hydrothermal method without using any surfactants. The SnO2nanostructures have been used as multidimensional frame for loading Pt nanoparticles for hydrogen evolution reaction.

Properties of Polyamide-6 Composites Reinforced with Hydroxyapatite Nanospheres

Hydroxyapatite nanospheres (nHA) were first synthesized from (NH4)2HPO4 and CaCl2 precursors in the presence of poly(vinyl alcohol) templates. The structure and morphology of as-synthesized products were examined by materials characterization techniques. X-ray diffraction patterns and Fourier transform infrared spectra showed that the nHA (50–70 nm) exhibit the crystalline structure and vibration bands of HA. The Ca/P molar ratio of nHA approached the stoichiometric value of 1.67. The nHA were then melt blended with polyamide-6 (PA6), followed by injection molding. Tensile and flexural measurements showed that the tensile and bending strengths of injection molded PA6–10 wt% nHA composite were close to those of human cortical bone. A simulated body fluid immersion test revealed that apatite crystals can be readily deposited on the PA6–10 wt% nHA composite surface after immersion for 30 days.

A Nonaqueous Approach to the Preparation of Iron Phosphide Nanowires

Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) have been used as surfactants, and oleylamine has been used as solvent. The crystalline structure and morphology of the as-synthesized products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained iron phosphide nanowires have a typical width of ~16 nm and a length of several hundred nanometers. Structural and compositional characterization reveals a hexagonal Fe2P crystalline phase. The morphology of as-synthesized products is greatly influenced by the ratio of TOP/TOPO. The presence of TOPO has been found to be essential for the growth of high-quality iron phosphide nanowires. Magnetic measurements reveal ferromagnetic characteristics, and hysteresis behaviors below the blocking temperature have been observed.

Synthesis, Characterization, and Photocatalytic Activity of Zn-Doped SnO2 Hierarchical Architectures Assembled by Nanocones

Zn-doped SnO2 hierarchical architectures with nanoflower, nanourchin, and nanotrepang morphologies have been synthesized with a surfactant-free solvothermal synthesis route in the mixed solvents of ethylenediamine (En), ethanol, and deionized water. The observations of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that Zn-doped SnO2 hierarchical architectures with different morphologies were assembled by the nanocones with diameters ranging from 20 to 60 nm. We found that the alkaline dosage (NaOH) of the solution had a remarkable effect on the morphology of as-synthesized products. The UV−visible spectra of Zn-doped SnO2 hierarchical architectures exhibited a blue shift with the decrease of the size of nanocones. The photocatalytic activity of Zn-doped SnO2 samples were evaluated by the degradation of RhB aqueous solution, and the results revealed that the sample with urchin morphology had high photocatalytic activity efficiency. Moreover, the degradation process of RhB induced by Zn-doped SnO2catalyst was investigated in detail as well.

Controlled synthesis of europium-doped lutetium compounds: nanoflakes, nanoquadrels, and nanorods

In this contribution, we report the successful preparation of large-scale and uniform europium-doped lutetium compounds with the varied morphologies of nanoflakes, nanoquadrels and nanorods, using colloidal Lu(OH)3–Eu at different concentrations as a precursor for the hydrothermal method (170 °C and pH = 13 for 24 h). The as-made products have different crystalline structures as well as different morphologies. The as-synthesized nanoflakes have a “perfect” square shape with side lengths of 220–400 nm and thicknesses of 50 nm or below. On the basis of the observed “non-perfect” nanoflakes, we have deduced a mechanism of “side wrapping” to describe the growth of the “perfect” square nanoflakes. The as-made nanoquadrels possess a sandwich-like nanostructure and they are all composed of several square nanoflakes via face-to-face “self-reorganization”. The formation of nanorods is due to the high chemical potential resulting from the high precursor concentration. At the same time, the pH value of the precursor and the method of mixing of the lanthanide nitrate solution with the NaOH solution have a great effect on the morphology of the as-synthesized products. The shapes of the as-made products were sustained after thermal decomposition to europium-doped Lu2O3. The crystalline structure, morphology and thermal behavior of as-synthesized products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TG) and differential scanning calorimetric analysis (DSC), respectively.

Synthesis and characterization of semiconductor zinc sulfide nanotubes by soft-template method

ZnS nanotubes have been successfully synthesized from solutions containing a surfactant, Triton X-100 (t-octyl-(OCH2CH2)×OH,x=9, 10). X-ray diffraction (XRD), transmission electron microscope (TEM) and selected area electron diffraction (SAED) are employed to characterize the structure and morphology of as-synthesized product. XRD and SAED pattern indicate that as-obtained products consist of pure polycrystalline cubic-phase ZnS structures. TEM images reveal that most of the products are tubular structures, with diameters ranging between 37–52 nm and lengths up to 3 μm. The wall thickness of as-obtained ZnS nanotube is around 9 nm. The growth mechanism of ZnS nanotubes has also be proposed.