A green hydrothermal route to GaOOH nanorods

GaOOH nanorods were synthesized by a green hydrothermal method at 200 °C using nanocrystalline Ga₂O₃ powders and distilled water as the starting materials, and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and thermogravimetric and differential scanning calorimetry (TG-DSC) analysis.     

Synthesis of sodium iron silicate(NaFe(III)[SiO3]2) nanorods and electrochemical characterization

Sodium iron silicate (NaFe(III)[SiO₃]₂) nanorods have been synthesized using iron nitrate (Fe(NO₃)₃) and sodium silicate (Na₂SiO₃) solutions by means of hydrothermal method. The mixture solution is processed in hydrothermal autoclave first at 180-200 °C for two days and then dried at 70 °C to obtain nanotructured NaFe(III)[SiO₃]₂. It was revealed that NaFe(III)[SiO₃]₂ nanorod with the average diameter of ~ 15 nm and length of several hundreds nm was confirmed by X-ray power diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cyclic voltammeter (CV) and electrochemical impedance spectra (EIS) investigations show that this kind of NaFe(III)[SiO₃]₂ nanostructures have evident and stable electrochemical redox behavior between potential range of − 0.1-0.55 V in alkaline solution.     

Sparse nanowire arrays for facile transport measurements

Nanowires can be electrodeposited into partially etched porous alumina templates such that only a very small number of nanowires reach the top surface of the template. This allows transport measurements of small clusters or single nanowires in their alumina matrix by connecting leads to the hemispherical domes marking the protrusion of nanowires on the surface. Copper, nickel, and silver nanowires have been synthesized in this manner, and a more general synthesis method is proposed.     

A facile approach to nanostructured hollow titania with high photocatalytic activity

Nanostructured hollow titania has been synthesized by a facile hydrothermal method in water/2-propanol mixed solution. The synthesized hollow titania is of anatase phase with a novel worm-like morphology. The wall thickness of this hollow structure can be conveniently controlled from about 100 nm to 380 nm and the inner cavity diameter from 300 nm to 130 nm by changing the water to 2-propanol ratio. The formation of the hollow worm-like titania could be attributed to the microheterogeneity of the water/2-propanol system. Furthermore, the as-synthesized product exhibits higher photocatalytic activity than that of commercial P25 in the methylene blue (MB) degradation reaction.     

A facile and green approach for the fabrication of ZnO nanorods using bamboo charcoal as the template

A green synthetic approach was presented for the fabrication of ZnO nanorods via the bamboo charcoal-assisted impregnation route with ZnC₂O₄ colloid in ethanol as the inorganic precursor, followed by calcination at 800 °C for 7 h in air. These ZnO samples were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is shown that wurtzite hexagonal structured ZnO nanorods were fabricated, with an average diameter of about 300 nm and a length up to several micrometers. Bamboo charcoal played a key role in the formation of ZnO nanorods. The possible formation mechanism for ZnO nanorods was proposed.     

A facile synthetic route to aqueous dispersions of silver nanoparticles

Stable aqueous dispersions of silver nanoparticles have been synthesized from an organometallic precursor dissolved in an organic phase. Hydrogen gas is used to reduce the precursor to form silver nanoparticles which spontaneously transfer into an immiscible aqueous phase where they are stabilized. This route provides a simple pathway for the preparation of aqueous nanoparticle solutions and avoids production of the inorganic ions that are usually associated with aqueous methods. The effectiveness of a variety of aqueous stabilizing agents is evaluated. All products show plasmon absorption bands characteristic of silver nanoparticles and transmission electron microscopy reveals most particles to be below 40 nm in diameter.     

Synthesis of polyaniline nanorods using sucrose stearate as soft template

Highly ordered polyaniline (PANI) nanorods were prepared by oxidative polymerization in the presence of sucrose stearate surfactant acting as a soft template and acetone as solvent. The polymerized PANI nanorods were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, and X-ray diffraction (XRD). Results showed that the concentration of sucrose stearate exhibited a strong influence on nanorods diameters, surfaces, and also the crystallinity of PANI. The diameters and crystallinity increase remarkably with increasing the sucrose stearate concentration. A mechanism for the formation of nanorods is also proposed. The steric hindrance of sucrose stearate molecules and hydrogen bonds formed between sucrose stearate and anilium ions or oligomers molecules play an important part in the formation of PANI nanorods.     

Characterization of Bi2S3 with different morphologies synthesized using microwave radiation

Bi₂S₃ with different morphologies (nanoparticles, nanorods and nanotubes) was synthesized using bismuth nitrate pentahydrate (Bi(NO₃)₃·5H₂O) and two kinds of sulfur sources (CH₃CSNH₂ and NH₂CSNH₂) in different solvents (water, ethylene glycol and propylene glycol) via a microwave radiation method at 180 W for 20 min. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that all of the products are orthorhombic Bi₂S₃ phase of nanoparticles, nanorods and nanotubes, influenced by the sulfur sources and solvents. Formation mechanisms of the products with different morphologies are also proposed.     

A facile method to prepare PbS nanorods

PbS nanorods with an average diameter of about 30 nm have been successfully prepared through a simple polyglycol-assisted route for the first time. The obtained PbS nanorods have been characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electronic diffraction (SAED). Experiments show that polyglycol plays an important role for the control of the morphology of PbS nanostructures. The preliminary result of the UV-vis absorption spectrum of the PbS nanorods is also presented.     

Raman scattering for the size of CdSe and CdS nanocrystals and comparison with other techniques

The sizes of the ensembles of CdSe regular nanocrystals (RNCs), CdSe magic-sized nanocrystals (MSNCs), and CdS RNCs were investigated by Raman scattering. The nanocrystal ensembles were synthesized via wet-chemistry approaches. The size distribution increases from CdSe MSNCs (2.26 nm), to CdSe RNCs (3.52 nm), and to CdS RNCs (3-8 nm and 4-10 nm). The sizes derived from Raman spectra are compared with those from other characterization tools such as UV/vis spectroscopy and transmission electron microscopy (TEM). The present study suggests that Raman scattering is an alternative and reliable technique for the determination of nanocrystal size and size distribution.     

A facile route to synthesize mesoporous zirconia with ultra high thermal stability

The mesoporous zirconia with ultra high thermal stability was synthesized via a controllable and facile sol-gel approach. It is found that the strong alkaline solution post-treatment exerted a critical influence on improving the thermal stability of the product. Even after calcination at 700 °C for 4 h, the worm-like mesopore system was fairly preserved in the post-treated product and the sample exhibited a high specific area (198 m² g⁻¹). Whereas for those samples without any post-treatment, its pore walls totally collapsed during calcinations above 400 °C, and the specific area drastically decreased.     

A novel technique to synthesize buserite-type manganese oxide thin film

Buserite-type layered magnesium manganese oxide has been prepared in a thin film form by means of the combination of electrochemical and ion-exchange processes. Mg²⁺ ions between the layers of buserite are stable toward ion-exchange with monovalent cations in solution while they can be excluded electrochemically for charge-compensation upon oxidation.     

A facile approach to synthesize N and B co-doped TiO2 nanomaterials with superior visible-light response

N and B co-doped TiO₂ nanoparticles were prepared by a facile one-step combustion reaction where Ti(OC₄H₉)₄ and H₃BO₃ were used as the precursors and urea served as the fuel and the N source. The formation of TiO₂ nanoparticles and the co-doping of N and B into the TiO₂ matrix lattices were achieved simultaneously. Our experimental results have shown that the optical absorption edges of the N and B co-doped TiO₂ nanoparticles significantly shift toward long wavelength compared to that of non-doped TiO₂ photocatalysts. The estimated optical bandgap of the N&B co-doped TiO₂ nanoparticles is 2.13 eV, which is much smaller than that of pure anatase TiO₂ (3.18 eV). We further studied the photocatalytic activity of the synthesized N&B co-doped TiO₂ nanoparticles through the decomposition of acetic acid, showing that the N&B co-doped TiO₂ exhibits superb photocatalytic activity and visible light response compared to one of the best commercially available TiO₂ photocatalysts, P25.     

A simple route to lanthanum hydroxide nanorods

This letter first describes a facile, low-cost, solution-phase approach to the large-scale preparation of lanthanum hydroxide single crystal nanorods at 60 °C without any template and surfactant. X-ray diffraction (XRD) shows that the nanorods are of pure hexagonal structure. The size and morphology of the products were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Lanthanum hydroxide single crystal nanorods are with diameters of approximately 20 nm and lengths of 150-200 nm. The processes of formation and decomposition for the as-prepared lanthanum hydroxide nanorods were discussed.     

A facile approach to synthesize rose-like ZnO/reduced graphene oxide composite: fluorescence and photocatalytic properties

Rose-like ZnO/reduced graphene oxide composites are synthesized by a simple, scalable, and facile route without using any surfactants. The well-defined ZnO microstructure has a hexagonal hierarchical rose-like architecture, which is composed of densely packed uniform thin flakes. The N,N-dimethylformamide/water system employed here acts as an organic solvent as well as a reagent, and two competing reactions give rise to the formation of the hexagonal hierarchical rose-like ZnO architecture. Compared with bare ZnO, the rose-like ZnO/reduced graphene oxide composite displays the fluorescence quenching property. Finally, the as-prepared products possess considerable photocatalytic property under visible light for the degradation of methylene blue.     

A simple molten salt method to synthesize single-crystalline potassium titanate nanobelts

Single-crystalline K₂Ti₆O₁₃ nanobelts with 100-300 nm in diameter and 10-50 μm in length have been synthesized via a facile and simple one-step solid-state chemical reaction method. The K₂Ti₆O₁₃ nanobelts were characterized by a range of methods including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDS), selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). Furthermore, the effects of the reaction temperature, the reaction time, and the weight ratio of reactants on the ultimate products are discussed.     

A novel solvothermal method to synthesize one-dimensional chains of indium tin oxide nanoparticles

One-dimensional conductive chains of indium tin oxide (ITO) nanoparticles with high specific surface areas of about 65 m² g^− 1 were synthesized from indium, tin acetylacetone complexes using isopropanol as solvent by a novel solvothermal method and post heat-treatment. When isopropanol was replaced with water as solvent, the non-conductive individual In₂SnO₅ nanoparticles were obtained.     

Solvothermal preparation of Bi2WO6 nanocrystals with improved visible light photocatalytic activity

Bismuth tungstate (Bi₂WO₆) nanocrystals with the average size of ca. 12 nm had been successfully synthesized by a simple solvothermal method at 180 °C for 2 h. The as-synthesized Bi₂WO₆ nanocrystals were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectra, and N₂ adsorption–desorption measurements. The visible-light-driven photocatalytic activity of the sample was evaluated by photo-degradation of rhodamine-B (RhB) at room temperature, which is much higher than that of the hydrothermal synthesized Bi₂WO₆ square plates and the commercially available TiO₂ (P-25). We believed that the high photocatalytic activity could be ascribed to the intrinsically small grain size and high surface-to-volume ratio associated with the Bi₂WO₆ nanocrystals.     

A simple L-cystine-assisted solvothermal approach to Cu3SbS3 nanorods

A simple L-cystine-assisted synthetic route has been successfully developed to prepare Cu₃SbS₃ nanorods under solvothermal conditions. In this synthetic system, we used CuCl₂ as the copper source, SbCl₃ as the antimony source, and L-cystine as both sulfur source and complexing reagent. The obtained Cu₃SbS₃ nanorods were characterized by XRD, XPS, FESEM and TEM (HRTEM). The results showed that the Cu₃SbS₃ nanorods were 100-150 nm in width and several micrometers in length. A possible formation mechanism for Cu₃SbS₃ nanorods was also discussed. The proposed solvothermal method using L-cystine as the sulfur source provides an alternative approach to prepare other ternary semiconductor nanomaterials.