Efficient rapid microwave-assisted route to synthesize InP micrometer hollow spheres

The efficiencies of two methods of synthesizing InP micro-scale hollow spheres are compared via the analogous solution-liquid-solid (ASLS) growth mechanism, either through a traditional solvothermal procedure, or via a microwave-assisted method. Scanning electronic microscopy (SEM) images show that most of the as-grown samples are micrometer hollow spheres, which indicates the efficiency of both methods. For traditional solvothermal route, long time (10 h) is necessary to obtain the desired samples, however, for the microwave-assisted route, 30 min is enough for hollow spherical products. An optimal choice of microwave irradiating time allows reducing the reaction time from hours to minutes. The proposed ASLS growth mechanism has also been discussed in detail.     

A novel synthetic route to prepare cubic BN nanorods

Cubic boron nitride nanorods were prepared at 450°C by a low pressure benzene thermal synthesis method using BCl₃ and Li₃N as the reactants. The nanorods with various lengths and diameters were observed by transmission electron microscopy. The analysis of X-ray diffraction pattern and electron diffraction pattern revealed that the nanorods are cBN with a lattice constant of 3.62 Å. The Fourier transformation infrared spectra showed that the dominant phase is cBN, and the B:N ratio of 1.15:1 can be obtained from the X-ray photoelectron spectrum.     

A novel solid-stabilized emulsion approach to CuO nanostructured microspheres

Nanostructured CuO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, TEM, XRD, size analysis and BET measurement were used to characterize the CuO microspheres. The average diameter of the CuO microspheres was 2.8 μm. The surfaces of the CuO microspheres were made of pin-like nanostructures with a pin diameter of 95 nm and a pin length of at least 600 nm. The XRD analysis indicated that the CuO nanostructured microspheres were of monoclinic lattice. The specific surface area of the CuO nanostructured microspheres was about 56.8 m²/g. A mechanism for the formation of the CuO microspheres with nanostructured surfaces was proposed.     

Synthesis of hierarchical Ni11(HPO3)8(OH)6 superstructures based on nanorods through a soft hydrothermal route

In this paper, we reported the successful synthesis of hierarchical Ni₁₁(HPO₃)₈(OH)₆ superstructures based on nanorods via a facile hydrothermal route, employing NiCl₂·6H₂O and NaH₂PO₂·H₂O as the reactants in the presences of polyvinylpyrrolidone (PVP) and CH₃COONa·3H₂O. The reaction was carried out at 170 °C for 10 h. HPO₃²⁻ ions were provided via the dismutation reaction of H₂PO₂⁻ ions in a weak basic solution. The as-obtained products were characterized by X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), field emission scanning electron microscopy (SEM), selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM). Some factors influencing the morphology of the hierarchical Ni₁₁(HPO₃)₈(OH)₆ nanorods, such as the reaction temperature, time, the amounts of PVP and CH₃COONa, and the initial concentration of Ni²⁺ ions, were systematically investigated. A possible growth mechanism was proposed based on experimental results.     

Synthesis and optical properties of ZnS hollow spheres from single source precursor

A facile one-pot synthesis of ZnS hollow spheres has been carried out via a chemical transformation induced inside-out Ostwald ripening process from a single source precursor. The size and shell thickness of the ZnS hollow spheres can be controlled by adjusting the reaction temperature and reaction time, respectively. Photoluminescence spectra show a dominant emission peak at 470 nm accompanied by several weaker peaks. UV-vis measurement reveals that the obtained ZnS hollow spheres exhibit “hollow effect”. The formation process of ZnS hollow spheres has been discussed.     

Bismuth subcarbonate nanoparticles fabricated by water-in-oil microemulsion-assisted hydrothermal process exhibit anti-Helicobacter pylori properties

Well-crystallized bismuth subcarbonate ((BiO)₂CO₃) nanoparticles were successfully synthesized by water-in-oil (w/o) microemulsion-assisted hydrothermal method. In this synthesis, bismuth citrate and urea are used as the precursors and the thermal decomposition of citrate leads to the formation of major carbonate anion. The reaction, nucleation and growth steps are confined inside the water droplets and hence uniform and well-crystallized spherical nanoparticles are formed. Importantly, these nanoparticles exert comparable anti-Helicobacter pylori activities to the clinically used drug, colloidal bismuth subcitrate (CBS), which offers a promise for development of new nanomedicines.     

Synthesis of stable spherical platinum diphosphide, PtP2/carbon nanocomposite by reacting Pt(PPh3)4 at elevated temperature under autogenic pressure

The synthesis of microsized carbon spheres supporting the semiconductor platinum diphosphide, PtP₂, was conducted by the thermal decomposition of an organometallic precursor. This novel reaction was carried out using the reaction under autogenic pressure at elevated temperature (RAPET) method by dissociating Pt(PPh₃)₄ at 1000 °C. The product was characterized using methods of electron microscopy (scanning electron microscope (SEM), transmission electron microscope (TEM), selected area energy dispersive spectroscopy (SAEDS), elemental analyzer (EA) and energy dispersive X-ray analysis (EDX)) and powder-XRD. Transmission electron microscope images indicate that the particle size of the nanoparticles of PtP₂ coated on the carbon spheres is 50 nm.     

Fabrication of hollow mesoporous NiO hexagonal microspheres via hydrothermal process in ionic liquid

The novel NiO hexagonal hollow microspheres have been successfully prepared by annealing Ni(OH)₂, which was synthesized via an ionic liquid-assisted hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption and Fourier transform infrared spectrometer (FTIR). The results show that the hollow NiO microstructures are self-organized by mesoporous cubic and hexagonal nanocrystals. The mesoporous structure possessed good thermal stability and high specific surface area (ca. 83 m²/g). The ionic liquid 1-butyl-3methylimidazolium tetrafluoroborate ([Bmim][BF₄]) was found to play a key role in controlling the morphology of NiO microstructures during the hydrothermal process. The special hollow mesoporous architectures will have potential applications in many fields, such as catalysts, absorbents, sensors, drug-delivery carriers, acoustic insulators and supercapacitors.     

Self-rising approach to synthesize hierarchically porous metal oxides

Hierarchically porous metal oxides are prepared using a novel self-rising approach. The method is ‘hard-template’ free and relatively easy to perform, utilizes inexpensive precursors and processing conditions, and is versatile, thus offering tremendous opportunities with a wide variety of conditions to explore to synthesize single or mixed metal oxides with hierarchically porous structures. Fe₂O₃, Sm_0.2Ce_0.8O_1.9, LaFeO₃, LaCoO₃, and La_0.5Sr_0.5Co_0.5Fe_0.5O₃ have been successfully synthesized while Fe₂O₃ and La_0.5Sr_0.5Co_0.5Fe_0.5O₃ as examples for single and mixed metal oxides have been studied in detail. Sm_0.2Ce_0.8O_1.9 has been applied as electrolyte for solid oxide fuel cells, showing good sinterability and high conductivity. A tentative scheme is provided to illustrate the pore formation mechanism using the self-rising approach.     

A novel solution-phase route for the synthesis of crystalline silver nanowires

A unique solution-phase route was devised to synthesize crystal Ag nanowires with high aspect-ratio (8-10 nm in diameter and length up to 10 μm) by the reduction of AgNO₃ with Vitamin C in SDS/ethanol solution. The resultant nanoproducts were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD) and electron diffraction (ED). A soft template mechanism was put forward to interpret the formation of metal Ag nanowires.     

Urchin-like Co2P nanocrystals: Synthesis, characterization, influencing factors and photocatalytic degradation property

In this paper, cobalt phosphides (Co₂P) nanocrystals with urchin-like structures have been successfully synthesized via a water-ethanol mixed-solvothermal route, employing white phosphorus (WP) and cobalt dichloride as starting reactants, sodium acetate as the pH adjustor, and sodium dodecyl benzene sulfonate (SDBS) as the surfactant. The as-obtained product was characterized by X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), (high resolution) transmission electron microscopy (TEM/HRTEM), selected area electron diffraction (SAED) and field emission scanning electron microscopy (FESEM). It was found that sodium acetate played an important role in the formation of Co₂P nanocrystals with urchin-like structures. Some factors influencing the morphology of the product, including the reaction temperature, time, amounts of WP and SDBS and so on, were investigated. The photocatalytic property of the product for the degradation of organic dyes was studied. A possible formation mechanism of urchin-like Co₂P nanocrystals was suggested based on the experiment results.     

Shape evolution of Cu2S nanostructures in Triton X-100/cyclohexane/water reverse micelles

The shape evolution of Cu₂S nanostructures, which were produced in Triton X-100/cyclohexane/water reverse micelles, was investigated by the transmission electron microscopy technique as a function of aging time, and the effect of the molar ratio of water to surfactant on the size and shape of Cu₂S nanostructures was also discussed. The results suggest that at the initial stage the nucleation process was dominant and the shape of Cu₂S nanostructures was preferably confined by the reverse micelle droplets and took spherical forms. With the extension of the aging time, the growth gradually governed the process and the shape of Cu₂S nanostructures evolved first to nanorods, and then to nanowires gradually. The formation of one-dimensional Cu₂S nanostructures is attributed to a directed aggregation growth process mediated by reverse micelle droplets, which was confirmed by high-resolution transmission electron microscopy. Furthermore, the size and shape of Cu₂S nanostructures can be controlled by changing the molar ratio of water to surfactant.     

Nickel titanate microtubes constructed by nearly spherical nanoparticles: Preparation, characterization and properties

In this paper, we report the successful synthesis of NiTiO₃ microtubes constructed by nearly spherical nanoparticles via a simple solution-combusting method employing a mixture of ethanol and ethyleneglycol (V/V = 60/40) as the solvent, nickel acetate as the nickel source, tetra-n-butyl titanate as the titanium source and oxygen gas in the atmosphere as the oxygen source. The as-obtained product was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). The UV-vis absorption spectrum of the product showed two absorption peaks centered at 258.6 and 350.1 nm, respectively. The Brunauer-Emmett-Teller (BET) surface area of the product was 14.06 m²/g and the pore size distribution mainly located from 20 to 30 nm. The photocatalytic degradation property of the product for organic dyes showed that the as-obtained porous NiTiO₃ microtubes could strongly promote the degradation of organic dyes including Pyronine B, Safranine T and Fluorescein.     

Preparation and characterization of lamellar-like Mg(OH)2 nanostructures via natural oxidation of Mg metal in formamide/water mixture

Facile, scale-up, and controllable fabrication of lamellar-like Mg(OH)₂ on a magnesium substrate through natural oxidation of Mg metal in formamide/water mixtures has been demonstrated. The one-step, wet-chemical approach has displayed well-controlled growth of densely packed magnesium hydroxide with large-area homogeneity and uniform morphology. The chemical-liquid-deposition process, an analogue to the widely used chemical-vapor-deposition technique, has been well developed for production of specific morphological Mg(OH)₂ through continuous supply, transport, and thermal decomposition of magnesium complexes in a liquid phase. The formation mechanism of lamellar-like Mg(OH)₂ was also discussed based on experimental phenomena.     

A novel route for the synthesis of nanotubes and fullerene-like nanostructures of molybdenum disulfide

The paper described the synthesis of nanotubes and fullerene-like nanostructures of MoS₂ through a technically simple, rapid, and energy-efficient microwave-assisted synthesis technique, which involved the use of elemental sulfur dissolved in a mixture of monoethanolamine and hydrazine hydrate as the sulfide source. The microwave induced reaction between the molybdate with sulfide ions, in the presence of hydrazine hydrate in the reaction medium, resulted in the formation of gray colored powders of amorphous MoS₂. The as-obtained powders were calcined at 600 °C for 2 h and characterized by different techniques. HRTEM analysis of the calcined samples indicated the formation of fullerene-like MoS₂ structures when the starting solution mixture was irradiated with microwave for a period of 200 s, while on 600 s of irradiation of the same revealed the formation of folded sheets like MoS₂ nanotubes. BET surface areas of the calcined samples have been measured and a plausible reaction mechanism for the formation of nanotubes and fullerene-like nanostructures of MoS₂ has been proposed.     

Cetyltrimethyl ammonium bromide assisted hydrothermal growth of hematite hollow cubes

Hematite hollow cubes have been prepared by forced hydrolysis of ferric chloride solutions under hydrothermal conditions. The effects of reaction time, reaction temperature and cetyltrimethyl ammonium bromide on the transformation process from akageneite to hematite were investigated in detail. The products were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. It is found that cetyltrimethyl ammonium bromide was a critical factor influencing the phase transformation process of akageneite and the final morphology of the as-prepared products. With cetyltrimethyl ammonium bromide, hematite hollow cubes and porous spheres were obtained. Otherwise only dense cubes were observed even prolonging reaction time or increasing reaction temperature. The mechanism was proposed.     

A mild solvothermal route to α-Fe2O3 nanoparticles

A mild solvothermal route has been developed to synthesize α-Fe₂O₃ nanoparticles using Fe(NO₃)₃ as a starting material. The results from XRD and TEM indicate the α-Fe₂O₃ powders possess a rhombohedrally centered hexagonal structure, and the size of particles from alcohothermal method at 160 °C is about 50-100 nm.     

Utilization of residual CdCl2 in CBD-CdS to realize grain growth in CdTe: A novel route

CdTe films were deposited by thermal evaporation onto chemical bath deposited CdS (CBD-CdS) films. The composite films were subjected to rapid thermal annealing (RTA) to observe simultaneous grain growth in both the CdS and CdTe layers. The films were characterized by measuring the compositional, microstructural and photoluminescence (PL) properties. PL spectra is dominated by the characteristic peaks (∼1.42 eV and ∼1.26 eV) associated with the virgin CdTe film. Additional features located at ∼2.56 eV and ∼1.99 eV could also be detected. The Fourier Transform Infra Red (FTIR) peak at ∼482 cm⁻¹ appeared due to the simultaneous presence of absorption peaks for CdTe stretching mode as well as Cd-S modes. Appearance of the broad peak between 1000 cm⁻¹ and 1165 cm⁻¹ may be an indication of interfacial alloying. Secondary ion mass Spectroscopy (SIMS) measurements were done to observe the compositional uniformity in the film and to measure the interfacial mixing behaviour.     

Branched silica nanostructures oriented by dynamic G-quadruplex transformation

Polymorphic G-quadruplexes including stacked G-quartet planes are potentially promising DNA templates beyond Watson-Crick duplexes to construct inorganic nanostructures. In this work, a novel G-rich oligonucleotide that can be modulated from the antiparallel G-quadruplex to multi-stranded supermolecular assemblies was designed. Based on this dynamic G-quadruplex transformation, an interesting leaf-vein silica nanostructure with regular branched intervals was constructed. The G-quadruplex assembly structure was found to play a significant role in the organization of the silica structures.