Simple Hydrothermal Reduction Research Articles

Mercury selenide nanorods: Synthesis and characterization via a simple hydrothermal method

HgSe nanorods have been synthesized through a simple hydrothermal reduction approach. The nanorods formed were ≈45 nm average diameter and ≈3 μm nm in length. X-ray diffraction characterization suggested that the product consists of cubic phase pure HgSe. The as-prepared products were also characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An X-ray energy dispersive spectroscopy (EDX) study further confirmed the composition and purity of the product. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the capping agent CTAB (cetyltrimethylammoniumbromide) plays a crucial role in the process. Other factors, such as the reaction time, temperature, different capping agent and the reductant type also have an influence on the morphology of the final products to some extent.

Platinum-Nanoparticle-Modified TiO2 Nanowires with Enhanced Photocatalytic Property

Highly crystalline Pt nanoparticles with an average diameter of 5 nm were homogeneously modified on the surfaces of TiO(2) nanowires (Pt-TiO(2) NWs) by a simple hydrothermal and chemical reduction route. Photodegradation of methylene blue (MB) in the presence of Pt-TiO(2) NWs indicates that the photocatalytic activity of TiO(2) NWs can be greatly enhanced by Pt nanoparticle modification. The physical chemistry process and photocatalytic mechanism for Pt-TiO(2) NWs hybrids degrading MB were investigated and analyzed. The Pt attached on TiO(2) nanowires induces formation of a Schottky barrier between TiO(2) and Pt naonoparticles, leading to a fast transport of photogenerated electrons to Pt particles. Furthermore, Pt incoporation on TiO(2) surface can accelerate the transfer of electrons to dissolved oxygen molecules. Besides enhancing the electron-hole separation and charge transfer to dissolved oxygen, Pt may also serve as an effective catalyst in the oxidation of MB. However, a high Pt loading value does not mean a high photocatalytic activity. Higher content loaded Pt nanoparticles can absorb more incident photons which do not contribute to the photocatalytic efficiency. The highest photocatalytic activity for the Pt-TiO(2) nanohybrids on MB can be obtained at 1 at % Pt loading.

Hydrothermal synthesis and characterization of bismuth selenide nanorods via a co-reduction route

Bi 2Se 3 nanorods have been synthesized through a simple hydrothermal reduction approach. The nanorods formed were ≈50 nm in average diameter and ≈4 μm nm in length. XRD characterization suggested that the product consisted of the rhombohedral phase of pure Bi 2Se 3. The products were also characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermo gravimetric analysis. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the capping agent CTAB plays a crucial role in the process. Other factors, such as the reaction time, the different capping agent and the sort of reductant also have influence on the morphology of the final products to some extent.

Simple synthesis and characterization of highly ordered sisal-like cobalt superstructures

Highly ordered sisal-like cobalt superstructures with novel turreted branches were prepared by a simple hydrothermal reduction route. The synthetic process involved the chemical reduction of cobalt ions and the oriented growth of cobalt nanocrystals under kinetic control independent of surfactants or external magnetic fields. The as-obtained products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and vibrating sample magnetometer (VSM). The sisal-like superstructures were found to be assembled by well-aligned turreted cobalt branches radiating from the center. The size and morphology of the products could be tailored by properly tuning the process conditions and the component of the reaction solution. The magnetic properties of the products were studied as well and the results demonstrate that the products presented ferromagnetic properties related to the corresponding microstructures. Based on a series of contrast experiments, the probable growth mechanism and fabrication process of the products were proposed. This work provides a simple and effective strategy to fabricate self-assembled cobalt hierarchical structures with novel and tunable morphologies.

Size-Controlled Synthesis of Magnetite (Fe3O4) Nanoparticles Coated with Glucose and Gluconic Acid from a Single Fe(III) Precursor by a Sucrose Bifunctional Hydrothermal Method

Size-controlled and coated magnetite nanoparticles with glucose and gluconic acid have been successfully synthesized via a simple and facile hydrothermal reduction route using a single iron precursor, FeCl3, and a combination of the inherent chemical reduction capability of sucrose decomposition products and their inorganic coordinating ability. The particle size can be easily controlled in the range of 4−16 nm. Results obtained with and without the addition of sucrose indicate that sucrose is required for the formation of nanoscale and coated magnetite instead of the much larger hematite. Mass spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetry analysis were used to investigate the formation mechanism of the coated nanomagnetite from the single Fe(III) precursor in sucrose. Sucrose acts as a bifunctional agent: (i) it decomposes into reducing species, causing partial reduction of the Fe3+ ions to Fe2+ ions as required for the formation of Fe3O4 an...

Synthesis and electrochemical properties of CuO nanobelts

CuO nanobelts have been successfully prepared with high yield via a simple hydrothermal reduction process at a low temperature. The as-prepared CuO nanowires were characterized by XRD, SEM, TEM and HRTEM techniques. The growth mechanism of these nanostructures is discussed. The electrochemical tests show that the ultrafine CuO nanobelts, as a promising electrode material, can deliver a large discharge capacity of about 500 mA h g −1 .

Controlled Synthesis of Cobalt Flowerlike Architectures by a Facile Hydrothermal Route

AbstractCobalt flowerlike architectures composed of hexagonal nanoplatelets have been synthesized by a simple hydrothermal reduction method. The architectures are fabricated by the reaction of CoCl2 with NaOH at 140–180 °C in the presence of sodium dodecyl benzenesulfonate (SDBS), with NaH2PO2·H2O as reducing agent. The diameters of the flowers range from 8 to 10 μm, and the average thickness of the hexagonal sheets is about 100 nm. Higher reaction temperatures and the proper concentration of sodium hydroxide (NaOH) are key requirements for the fabrication of the flowerlike architectures. A growth mechanism for these architectures is proposed on the basis of the characterization by X‐ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The magnetic hysteresis loops at 5 K and 295 K of the cobalt flowerlike architectures show ferromagnetic characteristics with coercivities of 371 Oe and 197 Oe, respectively. Our work may shed light on the designed fabrication of complex 3D architectures of other materials.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Synthesis and Characterization of Novel Three-Dimensional Metallic Co Dendritic Superstructures by a Simple Hydrothermal Reduction Route

Novel three-dimensional (3D) Co dendritic superstructures with an average diameter of ca. 15 µm were successfully prepared by a simple hydrothermal reduction route. The as-obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. It was shown that the 3D Co superstructures were comprised of dozens of well-aligned metallic Co dendrites with hierarchical assemblies radiating from the center. On the dendritic hierarchical structures, several leaves with different lengths and widths are connected to the main branch. The length of the main branch is several micrometers, and that of each leaf is about 0.5–1.5 µm with a width of 100−600 nm. A rational formation mechanism was proposed on the basis of the contrasting experiment. Compared with bulk cobalt, the 3D Co superstructures exhibited a decreased saturation magnetization (Ms) but an enhanced coercivity (Hc) due to their peculiar morphology.

A simple hydrothermal method for the growth ofBi2Se3 nanorods

Bi2Se3 nanorods have been synthesized through a simple hydrothermal reduction approach. The nanorods formedwere ≈10 nm in diameter and 100–200 nm in length. XRD characterizationsuggested that the product consisted of the hexagonal phase of pureBi2Se3. EDX and XPS studies further confirmed the composition and purityof the product. A possible mechanism for the reaction is proposed, whereBi2Se3 microsheets are presumed to be the intermediate for the formation of the nanorods. Theeffect of solvent on the morphology of the final product is discussed, where, in the presenceof aprotic solvent DMF, nanoparticle formation is observed. A bandgap of 2.25 eV isobserved from the UV–visible absorption spectra.

Synthesis and Characterization of Bi Nanorods and Superconducting NiBi Particles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and characterization of Bi nanorods and superconducting NiBi particles

Bi nanorods and NiBi particles were prepared using a simple hydrothermal reduction method at moderate temperatures of 150 °C. Transmission electron microscopy (TEM) reveals pure Bi nanorods with diameters of about 50 nm and superconducting NiBi particles. The magnetic susceptibility ( χ) of the superconducting NiBi was measured as a function of temperature at 10 Oe.

Synthesis, Characterization, and Growth Mechanism of Tellurium Nanotubes

A simple hydrothermal reduction method, employing sodium tellurate (Na2TeO4·2H2O) as tellurium source and formamide (HCONH2) as a reductant, was used to prepare and investigate tellurium nanotubes. The diameters of the nanotubes range from 200 to 600 nm and their lengths from 4 to 15 μm. Unlike studies reported previously,1,2 a series of electron microscopy characterization results suggests that the growth of tellurium nanotubes under the present experimental conditions is governed by a nucleation−dissolution−recrystallization growth mechanism: sphere-like tellurium nanoparticles initially formed in the hydrothermal system; the sphere-like nanoparticles were gradually dissolved to generate free tellurium atoms in the solution; these tellurium atoms were renewedly transferred onto the surfaces of the sphere-like nanoparticles and evolved into groove-like nanorods; the groove-like nanorods could be grown into tellurium nanotubes eventually.