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In this study, carbon fibers with different morphologies in their initial growth period have been obtained by the chemical vapor deposition using nano-copper particles as a catalyst at 250°C and then we have investigated the formation mechanism of the carbon fibers. Otherwise, we have noted that multi-branched carbon fibers with different morphologies were synthesized, and proposed the growth models for carbon fibers. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope, energy-dispersive x-ray were used to characterize the products.

Cu 2 O concave octahedron microcrystals with edge lengths of 5–10 μm were synthesized by reducing Cu 2+ with d -glucose in alkaline solution at 50 °C. The growth process of Cu 2 O was studied by field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). The results indicated that Cu 2 O concave octahedrons were formed by shape evolution of smaller regular octahedron as the edge lengths and concavity increased with time. It is also found that the reaction temperature has significant effect on the formation of Cu 2 O concave octahedrons. The formation of the concave octahedrons were explained to be due to selectively dissolution of {1 1 1} facets and preferential growth of {1 0 0} facets of the octahedron crystal.

Orthorhombic single-crystal CeCO 3 OH flower-like nanostructures have been successfully synthesized on a large scale by the hydrothermal method at 120 °C using Ce(NO 3 ) 3 ·6H 2 O as the cerium source, aqueous urea as both an alkaline and carbon source and polyvinyl alcohol as surfactant. Polycrystalline CeO 2 nanostructures have been obtained by thermal decomposition–oxidation of single-crystalline CeCO 3 OH flower-like nanostructures at 500 °C in flowing air. CeCO 3 OH flower-like nanostructures and CeO 2 nanostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), room temperature UV/vis absorption spectrum, differential scanning calorimetric analysis (DSC), and thermogravimetric analysis (TG). The high absorption in the UV region for CeO 2 nanostructures indicated that this material was suitable as UV-blocking material.

Carbon nanofibers have been synthesized by the thermal decomposition of acetylene with a copper nanocatalyst derived from cupric nitrate trihydrate at a low temperature of 260 °C. The resultant carbon nanofibers were characterized using transmission electron microscopy and X-ray power diffraction. The copper nanoparticles changed from initial irregular shapes to regular shapes during the growth of nanofibers. The copper nanoparticle size has a considerable effect on the morphology of carbon nanofibers. Helical carbon nanofibers with a symmetric growth mode were grown on copper nanoparticles with a grain size less than 50 nm. When the catalyst particle size was in the range of 50–200 nm, straight carbon nanofibers were obtained dominantly.

Single-crystalline cerium carbonate hydroxide (CeCO3OH) with shuttle morphology has been successfully synthesized by a facile hydrothermal method with the aid of polyvinyl alcohol (PVA). The typical diameters of CeCO3OH shuttles (middle part) are about 800 nm, and the typical lengths are about several micrometers. The shuttle morphology of CeCO3OH was sustained after thermal decomposition−oxidation to CeO2. Furthermore, the influence of surfactant on the crystal morphologies and luminescence properties of the CeCO3OH products are investigated.

Smaller cuprous oxides (Cu2O) nanocubes were synthesized by solution-phase method at 160 °C, using ethylene glycol reducing Cu(NO3)2·3H2O with poly(vinylypyrrolidone) (pvp) as capping agent. The Cu2O nanocubes were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray powder diffraction (XRD). SEM showed that most of Cu2O nanocubes were uniform and monodisperse, with the average edge length about 130 nm. The TEM results were consistent with the SEM results. Selected area electron diffraction (SAED) suggested that as-prepared Cu2O nanocubes were single crystalline. The geometric shape and size of Cu2O nanoparticles were greatly affected by the presence of PVP and its molar ratio (in repeating unit) relative to copper nitrate, temperature and the concentration of Cu(NO3)2·3H2O. The mechanism of Cu2O nanocubes formation was also discussed.

Propylene‐ethylene copolymer/calcium carbonate (CaCO3) composites (weight ratio=50/50) toughened with high density polyethylene (HDPE) were prepared using a twin‐screw extruder; the HDPE content in composites was in the range of 0–4 wt.%. The notched impact strength of propylene‐ethylene copolymer/CaCO3 composites with 1.5 wt.% HDPE was 46% higher than that of propylene‐ethylene copolymer/CaCO3 composites. Differential scanning calorimetry (DSC) experiments showed that good miscibility between propylene‐ethylene copolymer and HDPE enhanced the interpenetration of the macromolecules located in the interface. It was shown that debonding of the small HDPE particles within the propylene‐ethylene copolymer matrix resulted in the formation of small voids; the subsequent plastic deformation of the propylene‐ethylene copolymer matrix next to the voids thinned the ligaments and led to large energy consumption.

Amorphous Ni–P hollow microspheres have been synthesized on a large scale by using a template method via electroless deposition. Hollow glass microspheres were used as templates. Field-emission scanning electron microscopy, energy dispersive X-ray microanalysis system and X-ray powder diffraction were used to characterize such hollow microspheres. The liquid-phase nitrobenzene hydrogenation was used as a probe reaction to evaluate the catalytic activity of the obtained hollow microspheres. And the result shows that the amorphous Ni–P alloy hollow microspheres exhibit higher catalytic activity and stability than Raney-Ni catalysts.

In this study, carbon fibers with different morphologies, including coiled carbon nanofibers and straight carbon fibers, were obtained by the chemical vapor deposition using a Cu-catalytic pyrolysis of acetylene at 250 °C. The influences of nano-copper catalyst particle size and the reaction temperature on the morphology of carbon fibers were investigated. Under the same reaction condition, coiled carbon nanofibers generally were synthesized using nano-copper catalyst with smaller particles size, and bigger copper particles are apt to produce straight carbon fibers. With decreasing of reaction temperature to 200 °C, straight carbon fibers were obtained, instead of coiled carbon nanofibers at 250 °C. The product was characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD).

The helical carbon nanofibers (CNFs), synthesized at relatively low temperatures (lower than 250 deg. C) by using Cu as a catalyst, SiO{sub 2}, TiO{sub 2}, Al{sub 2}O{sub 3}, MgO as supports and acetylene as gas source, has been investigated. The products were characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The morphologies of obtained products influenced by the types of supports and weight ratios (Cu/support = 1:1, 1:5, and 1:10) were discussed. The average diameter of the helical CNFs was about 80 nm, and these CNFs had the same coil pitch, and coil diameter.

Helical carbon fibers were synthesized by the catalytic decomposition of acetylene as carbon source at low temperature of 240–260 °C with two nanocopper catalysts prepared by the hydrogen-arc plasma method and thermal decomposition of copper tartrate. Two growth modes for helical carbon fibers were obtained. One is mirror-symmetric growth mode, and the other is asymmetric growth mode. In the two growth modes, there were always only two helical fibers in regular shapes that were grown over a single copper nanoparticle. The two helical fibers had identical coil diameter, coil length, fiber diameter, cycle number, tight coil pitch, and cross section. In mirror-symmetric growth mode, the two helical fibers had absolutely opposite helical senses. The catalyst particle size was less than 50 nm and the coil diameter was

In this paper, cuprous oxide (Cu 2 O) nanostructures with different shapes, such as spheres, cubes and rods, have been synthesized by reducing copper nitrate trihydrate with ethylene glycol in the present of poly(vinylypyrrolidone) (PVP). The molar ratio of PVP (in the repeating unit) / Cu(NO 3 ) 2 ·3H 2 O and reaction temperature have significant effects on the formation and growth of these Cu 2 O nanostructures. The Cu 2 O nanorods were fabricated at the molar ratios of PVP/Cu(NO 3 ) 2 ·3H 2 O 2–3, while spherical and cubic nanoparticles were formed at the ratios of PVP/Cu(NO 3 ) 2 ·3H 2 O 5–7 and 10–15. Increasing with reaction temperatures, monodisperse particles were obtained. The as-synthesized nanoparticles and nanorods were investigated by transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD). With the as-prepared nanoparticles as catalyst, carbon nanofibers (CNFs) were synthesized by catalytic polymerization of acetylene at a lower temperature (250 °C). The effects of the catalyst particle sizes on the morphologies of the carbon fibers were studied.

Carbon-encapsulated copper nanoparticles were synthesized by a modified arc plasma method using methane as carbon source. The particles were characterized in detail by transmission electron microscope, high-resolution transmission electron microscopy, selected-area electron diffraction, X-ray diffraction, thermogravimetric and differential scanning calorimetry. The encapsulated copper nanoparticles were about 30 nm in diameter with 3–5 nm graphitic carbon shells. The outside graphitic carbon layers effectively prevented unwanted oxidation of the copper inside. The effect of the ratio of He/CH4 on the morphologies and the formation of the carbon shell were investigated.

The oriented ZnO nanorod arrays have been synthesized on a silicon wafer that coated with TiO2 films by aqueous chemical method. The morphologies, phase structure and the photoluminescence (PL) properties of the as-obtained product were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM) and PL spectrum. The nanorods were about 100 nm in diameter and more than 1 µm in length, which possessed wurtzite structure with a c axis growth direction. The room-temperature PL measurement of the nanorod arrays showed strong ultraviolet emission. The effect of the crystal structure and the thickness of TiO2 films on the morphologies of ZnO nanostructures were investigated. It was found that the rutile TiO2 films were appropriate to the oriented growth of ZnO nanorod arrays in comparison with anatase TiO2 films. Moreover, flakelike ZnO nanostructures were obtained with increasing the thickness of anatase TiO2 films.

Helical carbon nanofibers are synthesized by thermal chemical vapor deposition using copper nanocrystals as a catalyst and acetylene as a source gas at the low temperature of 195 °C. These nanocoils are symmetrically grown on copper nanocrystals in the form of twin helices. They contain high content of hydrogen. Their molecular structures are different from polyacetylene. They can be classified as a new type of amorphous carbon nanofibers. They present novel elasticity and interesting processability. The twin helices exhibit not only the reversible extension of the nanocoil itself but also the reversible angle change between the two nanocoils. They can be easily separated into two by electron beam heating. However, if a certain section of the nanocoil is heated by electron beam in a scanning mode, it will adjust its structures along the scanning line of the electron beam.

Large-scale of oriented Polyaniline nanorods have been synthesized by one-step electrochemical deposition on aluminium electrode without the aid of any templates. The diameters and lengths of polyaniline nanorods are in the range of 50–60 nm and 150–250 nm, respectively. The morphologies and molecular structures of the film are characterized by field-emission scanning electron microscopy (FE-SEM), Ultraviolet-Visual (UV-vis) and Fourier transform infared (FTIR). The effects of synthetic parameters, such as the concentration of aniline and electric current intensity, on the morphologies of polyaniline films are investigated.

A new type of amorphous helical carbon nanofibers has been synthesized using copper nanocatalysts and an acetylene gas source at atmospheric pressure. The nanofibers are grown at 468 K, which is the lowest temperature by ordinary metal-catalyzed thermal chemical vapor deposition of hydrocarbon, and exhibit a symmetric growth mode in the form of twin helices. IR, XRD, Raman, and C/H molar ratio analyses reveal a polymer-like structure with a weak trans-polyacetylene feature. The nanofibers are a mixture of solid polymers and a small amount of carbon. A reaction mechanism has been proposed on the basis of the previous studies of acetylene adsorption, desorption properties, and surface reactions on copper (111), (110), and (001) planes under ultrahigh-vacuum (UHV) conditions as well as the results obtained in our study. The reaction mechanism of acetylene on copper single-crystal surfaces under UHV conditions indeed reflects the reaction mechanism under practical catalytic conditions at atmospheric pressure. The nanofibers grow mainly via acetylene coupling to solid polymers on copper nanocrystal surfaces. Acetylene also couples to yield small amounts of liquid oligomers and gaseous products, and undergoes slight carbon deposition during the fiber growth.

Spherical titanium suboxide nanoparticles (Ti 5 O 9 , Ti 9 O 17 , TiO) are synthesized by arc plasma. A mixture of Ar, H 2 and H 2 O at 10 mbar pressure is used as the working gas. The variations of the proportion of H 2 O in the mixture gas during the synthesis induce a clear change in the size, color, composition, and optical properties of these nanoparticles. A reduction of H 2 O partial pressure reduces the grain size of the product. The titanium suboxide nanoparticles (Ti 5 O 9 , Ti 9 O 17 ) show a blue luster. The UV–Vis–NIR absorption spectra present a substantial absorption in the range 400–800 nm. In particular, there is a uniform and stable absorption from 800 to 3000 nm. FT-IR spectra reveal the H 2 O partial pressure significantly affects the –OH groups content on the surface or in the bulk of the nanoparticles.

Polyaniline nanobelts have been synthesized by a self-assembly process using the chemical oxidative polymerization of aniline in a surfactant gel. The morphologies of polyaniline nanostructures were characterized by field-emission scanning electron microscopy and transmission electron microscopy. The effects of the concentrations of cetyltrimethylammonium bromide on the morphologies of polyaniline nanostructures have also been investigated.

In this work we report the synthesis of tantalum nanoparticles from bulk tantalum by hydrogen arc plasma method. The product obtained was investigated by ultraviolet (UV)–visible spectrum, X-ray diffractometer (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) analysis. The size of these particles is less than 10 nm and there are few defects on their surface. A strong ultraviolet absorption below 320 nm was observed. XRD analysis revealed that the product consist of tantalum and hexagonal δ-TaO nanoparticles. The tantalum nanoparticles were easily oxidized in the air to form δ-TaO due to high activity. The thermal stability of sample was analyzed by thermogravimetry/differential scanning calorimetry (TG/DSC) in the ambience of dry N2 (containing less than 1% of oxygen).

Helical carbon nanofibers with a symmetric growth mode were synthesized by the decomposition of acetylene with a copper catalyst. There were always only two helical fibers symmetrically grown over a single copper nanocrystal. The two helical fibers had opposite helical senses, but had identical cycle number, coil diameter, coil length, coil pitch, cross section, and fiber diameter. The irregular tips and helical reversals of the two helical fibers further revealed the symmetric growth mode. This mirror-symmetric growth mode was induced by the shape changes in copper nanocrystals during catalyzing the decomposition of acetylene. Upon contacting the initial copper nanocrystals with irregular shapes, acetylene began to decompose to form two straight fibers (the irregular tips). At the same time, shape changes in copper nanocrystals began. Once they changed from an irregular to a regular faceted shape, the two straight fibers ceased to grow and two regular helical nanofibers with opposite helical senses began to grow. If the regular faceted nanocrystals continue to change shapes during fiber growth, the two helical fibers possibly changed helical senses at the same time, resulting in helical reversals. The shape changes were caused by the changes in surface energy resulting from the acetylene-adsorption on the copper nanocrystals.

Carbon nanofibers (CNFs) and carbon nanotubes (CNTs) were synthesized at different temperatures by the catalytic pyrolysis of acetylene with iron nanoparticles prepared using a hydrogen-arc plasma method. The obtained carbon nanomaterials were characterized by transmission electron microscopy and field-emission scanning electron microscopy. An iron nanoparticle was always located at the tip of CNFs or CNTs, whose diameter was approximately identical with the diameter of the iron nanoparticle. The structures of the products were closely related to the reaction temperature, and could be changed from fibers to tubes by simply increasing the temperature. CNFs were obtained at the reaction temperature of 550–650 °C. When the reaction temperature was increased to 710–800 °C, CNTs were obtained.

A simple route that utilizes carbon nanofibers as templates for preparing metal or alloy nanotubes via electroless deposition is developed. SEM and TEM images of the prepared Ni–Ni 3 P nanotubes are presented. In this method, it is easy to control the size or the shape of the prepared metal nanotubes by using different carbon or other nanofibers as templates.

Bundle-like structures consisting of single crystal cerium hydroxide carbonate (Ce(OH)CO 3 ) nanorods have been synthesized successfully by a hydrothermal method at 100 °C using cerium nitrate (Ce(NO 3 ) 3 ·6H 2 O) as the cerium source, aqueous carbamide both as an alkaline and carbon source and cetyltrimethylammonium bromide (CTAB) as surfactant. X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to characterize such bundle-like structures. SEM and TEM images show that Ce(OH)CO 3 bundle-like structures were composed of nanorods with diameters of ∼ 100 nm. The XRD pattern and electron diffraction (ED) pattern indicate that Ce(OH)CO 3 has a pure orthorhombic single crystal structure.

A hydrogen arc plasma method for preparing nano-particles was introduced. A method which possesses higher production rate, lower energy consumption and is suitable for preparation of nano-particles of metals with high melting point. The microstructures and properties of the nano-particles prepared by this method were reported.

Nanoscale copper and silver were synthesized by the H2+Ar arc plasma method. During the synthesis, hydrogen molecules were dissociated into hydrogen atoms and stored in the particles. At the same time, nanometer copper and silver particles were prepared by the inert gas condensation method whose power is about identical with the hydrogen arc plasma method. Various specimens were annealed respectively at low temperature. The particle size was measured by a transmission electron microscopy. A proper temperature was chosen to prepare the standard specimen.

We show the successful growth of ZnO layer and tubular structures on silicon substrates by a simple hydrothermal method. The products were characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffractometer (XRD). SEM images show that the nanotubes with outer diameters in the range of 120–250 nm, and wall thickness in the range of 30–50 nm. In addition, it was found that there were many incomplete ZnO nanotubes, which indicated that they were formed by scrolling of layer structure. And the possible growth mechanism was proposed. XRD shows that ZnO layers and nanotubes have hexagonal wurtzite structure.

Single-crystal cerium hydroxide carbonate (Ce(OH)CO3) triangular microplates with the hexagonal phase have been successfully synthesized by a hydrothermal method at 150 degrees C using cerium nitrate (Ce(NO3)3.6H2O) as the cerium source, aqueous carbamide as both an alkaline and carbon source, and cetyltrimethylammonium bromide (CTAB) as a surfactant. Single-crystal ceria (CeO2) triangular microplates have been fabricated by a thermal decomposition-oxidation process at 650 degrees C for 7 h using single-crystal Ce(OH)CO3 microplates as the precursor. The shape of the Ce(OH)CO3 microplate was sustained after thermal decomposition-oxidation to CeO2. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), differential scanning calorimetric analysis (DSC), and thermogravimetric analysis (TG).

A new kind of Ce-Ni nanoparticle was prepared by hydrogen arc plasma method. The nanoparticles consist of a large Ni core and a thin outer shell of CeNi alloy and CeO2. A large quantity of hydrogen was stored in the particles, which was released at about 400 °C. The particles possess a lot of defects, dislocations and twin faults, which increase the number of surface active centers of the particles. The mechanism of shell structure formation of the nanoparticles is discussed in terms of the low solubility of Ce in Ni, and surface segregation under non-equilibrium cooling conditions.

Nanostructured TiO 2 with an average grain size of 40 nm was synthesized by the gas condensation technique followed by consolidation and sintering. Pellets of 15 mm diameter and 0.5 mm in thickness were deformed plastically by a gas pressure forming technique. Gas ressures were varied between 100 and 250 kPa, resulting in stresses in the range of 2 to 20 MPa; deformation temperatures varied from 700 to 800°C. After deformation with strains ϵ up to 0.1 the samples did not show any evidence of crackformation. The total deformation at the center of the sample disk, i.e. the apex height, was larger than 2 mm and strain rates were as large as 4 x 10 −6 s −1 . These experiments show for the first time that nanostructured ceramics can be deformed plastically under tensile stresses below half the melting point. Although the total strain is still small, larger deformation and net shape forming should be possible by this technique, enabling technological applications of nanostructured ceramics.

[reaction: see text] Helical polyacetylene fibers with absolutely symmetric structures were prepared by polymerization of acetylene using copper tartrate as a catalyst. There were always only two coiled polyacetylene fibers grown on a single copper nanocrystal. The two coiled fibers had absolutely opposite helical senses but were identical in cycle number, coil diameter, coil length, coil pitch, and fiber diameter.

In this work, Y-shaped carbon fibers with high purity were successfully synthesized by CVD using copper tartrate as a catalyst precursor at low reaction temperature, 279 °C. A model has been proposed for interpreting the mechanism of the Y-shaped carbon fibers growth. It is suggested that the introduction of hydrogen is the key factor to the formation of three carbon fibers growth faces on every the agglomeration of copper monocrystalline catalyst particles and lead to the formation of Y-shaped carbon fibers subsequently. The Y-shaped carbon fibers were characterized by field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction.

By using a double-aberration-corrected (scanning) transmission electron microscope (STEM/TEM) at an acceleration voltage of only 80 kV, we demonstrate that, due to the low solubility of copper (Cu) in carbon and its affinity with oxygen (O), single-crystal Cu catalysts dissociate into small cuprous oxide (Cu2O) nanoparticles after the growth of carbon nanofibers, and Cu2O nanoparticles ultimately localize on the fiber surfaces. This new finding is a step toward a better understanding of the interactions between Cu catalysts and carbon nanomaterials and could suggest a simple and effective method for eliminating Cu impurities from the fibers.

The oriented ZnO nanotube arrays have been synthesized by a chemical solution method on a silicon wafer coated with ZnO thin films via thermally decomposing zinc acetate at 280°C. The morphologies, phase structure and the photoluminescence (PL) properties were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM) and photoluminescence (PL) spectrum. It was found that the outer diameters of the ZnO nanotube ranges from 200nm to 300 nm, and the wall thickness is in the range of 30nm to 40 nm. ZnO nanotubes prefer to grow along the c axis. Photoluminescence (PL) spectrum shows a strong UV emission peaks at ~380 nm and a broad green-yellow emission at ~ 580 nm.

Copper nanowires with high aspect ratios were synthesized by solventhermal reduction of Cu2+ in H2O/CTAB/n-butanol/n-hexane reverse microemulsion system with a water to surfactant molar ratio (?) = 40. The synthesized products were studied by XRD, SEM, and TEM respectively. The phase structure of the products was cubic face-centered Cu as straight nanowires with an average diameter of ~20 nm and lengths up to 2 ?m. It was found that higher water content (?=40) favored the formation of nanowires with high aspect ratios. The evolution of the nanowires was unidirectional with constant diameters. In aqueous solution experiments, flower-like microspheres consisted of short nanorods were obtained, which indicated that the microemulsion system was a crucial prerequisite for the formation of nanowires with high aspect ratios. A tentative formation mechanism of the nanowires is proposed, which involves unidirectional crystal growth as a consequence of irreversible micellar fusion, micellar longitudinal exchange and coalescence of micelles.

In this paper, the synthesis of carbon fibers (CFs) with different morphology, that is, coiled carbon nanofibers with symmetrical structure and Y-shaped carbon fibers was presented by using copper tartrate as catalyst precursor at low temperature, 279 °C. Hydrogen and commercial acetylene or commercial acetylene only was introduced into the reaction tube, respectively, during the synthesis reaction, the introduction of hydrogen will be the key factor to the formation of Y-shaped carbon fibers. According to the analysis, the growth model for carbon fibers has been established. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy were used to carry out the product characterization.

Mesoporous SiO2/Ni3Si2O5(OH)4 core-shell microspheres with tunable chamber structures have been synthesized by the reaction between Ni(Ac)2.4H2O and SiO2 microspheres via a simple self-template approach.