Synthesis of ZnO nanorods by the thermal reduction process of a mixture of ZnO and Al powder

Single‐crystalline Zinc oxide (ZnO) nanorods were firstly synthesized on gold‐coated Si substrate via a simple thermal reduction method from the mixture of ZnO and Al powder. The growth process was carried out in a quartz tube at different temperature (550‐700 °C) and at different oxygen partial pressure. Their structure properties were investigated by X‐ray diffraction (XRD), scanning electron microscope (SEM), X‐ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The length of the as‐prepared ZnO nanorods was up to several micrometers and their diameters were about 130 nm. The X‐ray diffraction patterns, transmission electron microscopic images, and selective area electron diffraction patterns indicate that the one‐dimensional ZnO nanorods are a pure Single‐crystal and preferentially oriented in the [0001] direction. The reaction mechanism of ZnO nanorods was proposed on the basis of experimental data. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Microstructure of a genuine Damascus sabre

The surface and cross‐section of a genuine Damascus sword was characterised by means of wide‐angle X‐ray scattering techniques complemented by optical and transmisssion electron microscopy. Position‐resolved X‐ray phase analysis revealed that, unlike ferrite and martensite, the distribution of cementite is inhomogeneous in different spatial zones parallel to the cutting edge of the blade. For the first time a quantitative X‐ray phase and texture analysis was made possible by averaging all spatial zones of the surface and the cross‐section of the sword and applying the Rietveld method with code TOPAS. Differences concerning texture and structure characteristics of ferrite, martensite and cementite are discussed. More evidence for the structure of cementite nanowires is supplied. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and morphology of nanosized zeolite L

AFM is a powerful tool for imaging nanoscale surface features; it provides two and three dimensional crystal structure images and other information about actual surface of zeolite crystallites. In this paper, nanosized zeolite L is synthesized in different crystallization times and a study of crystal growth of zeolite L is reported using atomic force microscopy (AFM). X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques are used for characterization of the as synthesized samples. TEM and two‐dimensional AFM images indicate that the zeolite particles are in a nano‐range and they have hexagonal structure. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of substrate temperature on the properties of reactively sputtered TiN/NbN multilayers

TiN/NbN multilayer coatings were deposited with various substrate temperatures by DC reactive magnetron sputtering method onto Si (111) and glass substrates. The effect of substrate temperature on the structural and optical properties of TiN/NbN multilayers was investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, Field emission scanning electron microscopy and Photoluminescence measurements. The composition was analyzed by X‐ray photoelectron spectroscopy. X‐ray diffraction results showed that the layers crystallized in cubic structure for TiN and hexagonal structure for NbN. It was found that grain size increased with increase in substrate temperature. The surface morphology of the TiN/NbN thin films showed a dense and smooth surface with substrate temperature upto 200 °C but after 300 °C, the grains became larger and coarse surface was observed. The TiN/NbN multilayer coatings exhibited the characteristic peaks centered at 180, 210 and 560 cm^‐1. Red band emission peaks were observed in the wavelength range of 700‐710 nm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Zr‐doped CeO2 Hollow slightly‐truncated nano‐octahedrons: One‐pot synthesis,characterization and their application in catalysis of CO oxidation

Zirconium‐doped ceria hollow slightly‐truncated nano‐octahedrons (HTNOs) (Ce_1‐xZr_xO₂) were synthesized by a one‐pot, facile hydrothermal method. The morphology and crystalline structure were characterized with powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and the high resolution transmission electron microscopy (HRTEM). The composition and chemical valence on the surface of the as‐prepared Ce_1‐xZr_xO₂ powders were detected by X‐ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry (EDS). The surface area and pore size distribution of as‐obtained Zr‐doped ceria HTNOs were measured by N₂ adsorption‐desorption measurement. Mechanisms for the growth of Zr‐doped ceria HTNOs are proposed as both oriented attachment and Ostwald ripening process and the formation of the hollow structure is strongly dependent on the addition of Zr⁴⁺ ions. Furthermore, the as‐obtained Zr‐doped ceria HTNOs revealed superior catalytic activity and thermal stability toward CO oxidation compared to pure ceria. It may provide a new path for the fabrication of inorganic hollow structures on introducing alien metal ions.     

Structural and morphological studies on Mn substituted ZnO nanometer‐sized crystals

Mn substituted ZnO nanocrystals synthesized by a co‐precipitation method. X‐ray diffraction (XRD) studies confirms the presence of wurtzite (hexagonal) crystal structure similar to un doped ZnO, suggesting that doped Mn ions go at the regular Zn sites. The lattice parameters a and c are increasing with increasing Mn content. The unit cell volume increases with increasing Mn concentration, indicating the homogeneous substitution of Mn²⁺ for the Zn²⁺. The lattice distortion parameter (ε_v) is evaluated from XRD data and found that it enhances as Mn content increases. Transmission electron microscopy photographs show that the size of the ZnO crystals is in the range of 20‐50 nm. The SAED pattern confirms the hexagonal and crystalline nature of the samples which are in agreement with X‐ray analysis. The chemical groups of the samples have been identified by FTIR studies (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ethylenediamine inducing growth of {100} facets exposed PbS nanosheets

A simple ethylenediamine‐assisted hydrothermal method was developed for the synthesis of sheet‐like PbS nanostructures. Studies show that ethylenediamine not only provides a weakly basic environment for the reaction system, but also acts as a capping reagent to control the growth habit of cubic PbS. A reasonable growth mechanism for the PbS nanosheet structure has been proposed on the basis of the experimental studies. The structure, morphology, and composition of the nanosheets have been characterized by X‐ray powder diffraction, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and transmission electron microscopy.     

Fabrication of ferric oxide/reduced graphene oxide/cadmium sulfide heterostructure photoelectrode for enhanced photoelectrochemical performance

A novel high‐efficiency photoelectrode (Fe₂O₃/reduced graphene oxide/CdS) built from heterostructure and conductive scaffold has been successfully designed and synthesized. Reduced graphene oxide works as a “bridge” which benefits for electron and hole transport. The obtained heterostructure photoelectrodes were systematically characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The photoconversion efficiency (η) and photocurrent densities vs. time (I‐t) curves responding to monochromatic lights have been further investigated in‐depth, which reveals that introduction of CdS and reduced graphene oxide played an important role in the enhancement of photoelectrochemical performance.     

α‐Fe2O3 nanospindles loaded with ZnO nanocrystals: Synthesis and improved gas sensing performance

ZnO/α‐Fe₂O₃ nanocomposites were fabricated through a two‐step hydrothermal method. The morphology and composition of the as‐synthesized products were characterized by X‐ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectroscopy (EDS), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The gas sensing properties of the fabricated products were investigated towards ethanol, acetone, propanol, isopropanol, formaldehyde, chloroform and so on. The results demonstrated that the ZnO/α‐Fe₂O₃ nanocomposites exhibited excellent sensing properties and showed remarkably higher sensing responses and much lower optimum operating temperature compared to individual ZnO and α‐Fe₂O₃. In addition, the ZnO/α‐Fe₂O₃ nanocomposites have some selectivity for ethanol, propanol and isopropanol. The possible gas sensing mechanism was also proposed. Our studies demonstrate that our fabricated materials could be widely used in the future.     

Elliptic NdCrO3 microplate by a simple one‐step hydrothermal synthesis route and its characterization and magnetic properties

Elliptic NdCrO₃ microplates were synthesized by a simple and facile one‐step hydrothermal method of processing temperature 280 °C for 3 days. The products prepared in this paper have been characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), X‐ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR) and field‐emission scanning electron microscopy (FESEM). The magnetic properties of the final sample are also studied. The XRD pattern indicates the pure orthorhombic phase for NdCrO₃ particles, the XPS, XRF and FTIR results further demonstrate the composition and purity of the final product. A possible growth mechanism for elliptic NdCrO₃ microplates is proposed. Through the investigation of magnetic properties, it can be generally concluded that the orthorhombic elliptic NdCrO₃ microplates exhibit typical behaviors of magnetic transition, spin reorientation transition and magnetic exchange bias. The Néel temperature is 218 K and the spin reorientation transition temperature is 46 K. The hysteresis loop under 5 K shows that the value of exchange bias field (H_ex) is 12 Oe and the shift of remanent magnetization (ΔM) is 0.008 emu/g, respectively.     

Structural and catalytic properties of Cu2S microrods grown on a three‐dimensional substrate

We present a facile solution‐phase method for the synthesis of Cu₂S microcrystals with rod‐like morphologies by the reaction of sulfur with three‐dimensional substrate copper foam in a mixed solvent of ethylene glycol and deionized water. The lengths of Cu₂S microrods are between 80 and 150 μm and the diameter is among 3 to 8 μm. Monodisperse Cu₂S microrods self‐assemble into echinus structure. The samples were characterized by X‐ray powder diffraction and scanning electron microscopy. Energy dispersive X‐ray spectroscopy was further used to testifiy the purity of Cu₂S. Catalysis performance proved that the obtained Cu₂S materials possess superior catalytic efficiency on methylene blue with the assistance of H₂O₂. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solvothermal synthesis of flower‐like lanthanum tartrate and lanthanum oxide microspheres in ethanol‐water mixed system

Monodispersed lanthanum tartrate microspheres with flower‐like shape were synthesized by a mild solvothermal method using ethanol‐water mixed system as the solvent. Lanthanum oxide with reserved spherical shape was subsequently fabricated by a following calcination process. X‐ray diffraction analyses (XRD), X‐ray spectroscopy (EDS), scanning electron microscopy (SEM), thermogravimetry‐differential thermal analysis (TG‐DTA) were employed to characterize the composition, structure, and morphology of the products. The lanthanum tartrate microspheres were aggregated by nanosheets as petals. Size of the aggregation and thickness of the petal vary with the vol.% of ethanol. As the vol.% of ethanol increases the degree of aggregation and the thickness of the petal decrease, and other properties such as the size distribution, dispersion are also modulated. These alterations can be interpreted by the changing dielectric constant of mixed solvent. Such lanthanum tartrate can be applied to fabricate micro‐sphereshaped lanthanum oxide after calcination. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Floating zone growth and characterization of ruby single crystals

Large, high optical quality single crystals of ruby have been grown successfully by the floating zone method under air atmosphere. The size of the grown crystal is typically 60‐70 mm in length and 7‐8 mm in diameter. The obtained crystals were red and did not have any macroscopic defects such as cracks and inclusions. Grown crystals were characterized by powder X‐ray diffraction (XRD) methods, polarized optical microscopy, scanning electron microscopy (SEM). The absorption and fluorescence spectra were measured at room temperature and the dielectric constant measurements of ruby crystals were also presented. Defects occurring in single crystals of ruby during crystal growth by floating zone method are described, and their correlation with the growth parameters is discussed. The origin and control of these defects in grown crystals were studied and the optimum method was proposed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Simple extraction‐solvothermal synthesis of single‐crystalline silver microplates

Single‐crystalline silver microplates, with average edge length of about 1.5 μm and thickness of 100 nm, have been synthesized by a simple extraction‐solvothermal method. Samples were characterized in detail by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM) and High‐resolution transmission electron microscopy (HRTEM) technologies. Extractant primary amine N1923 can also act as reducing agent. It has been found that microstructure of the silver can be controlled by the n‐octanol during the solvothermal treatment. Based on a series of experimental analysis, the possible formation mechanism of these microplates was discussed briefly. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and characterization of magnetite nanocrystals

Nanocrystals of magnetite (Fe₃O₄) were prepared by sol‐gel technique. The prepared nanocrystals were characterized for phase by powder X‐ray diffraction (XRD) of the samples annealed at successively higher temperature. The magnetite phase was formed during the annealing of the synthesized powder at 400 °C for a few hours. The Fourier transform infrared spectroscopy (FTIR) was performed to analyze the functional groups in the material. The energy dispersive X‐ray diffraction (EDAX) was performed for chemical composition analysis. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques were used to analyze the morphology of nanocrystals and for estimating their average size. The results confirm the formation of Fe₃O₄nanocrystals of the sizes ∼20–50 nm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Fabrication and photocatalytic property of CuO nanosheets via a facile solution route

Two‐dimensional (2D) CuO nanosheets were fabricated on Cu foils using a solution method. The method was novel, easy and can be completed at room temperature in the absence of any surfactant. The obtained materials were characterized by X‐ray diffraction (XRD), X‐ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM) and ultraviolet‐visible (UV‐Vis) spectroscopy. The effects of reaction time and temperature on the morphology and formation of CuO nanosheets were investigated, and a possible mechanism for the formation of CuO nanosheets was proposed. Experiments demonstrated that the formation of CuO nanosheets were significantly influenced by the growth time, and the reaction temperature was a key factor in determining the size of CuO nanosheets. Photocatalytic performance of CuO nanosheets was evaluated by measuring the decomposition rate of methyl orange solution. About 93% of the methyl orange was degraded after 150 min, which was much more efficient than that of CuO nanoparticles.     

Synthesis and characterization of manganese sulphide thin films deposited by spray pyrolysis

Manganese sulphide (MnS) thin films have been deposited onto glass substrate by a low cost spray‐pyrolysis technique at 220 °C. The as‐deposited MnS thin films have been characterized using scanning electron microscopy (SEM), energy dispersive X‐ray (EDX) spectroscopy, atomic force microscopy (AFM), X‐ray diffraction, UV visible spectroscopy and photo electrochemical (PEC) measurement. The SEM and AFM images showed that the MnS thin films were well covered onto the substrate surface. The as‐deposited raw thin film was found to be amorphous in nature and perfectly crystalline phase after annealing the sample. Optical band gap of the MnS thin films was found to vary from 3.1 to 3.21 eV and the band gap decreases with the increase in film thickness. Optical constants such as refractive index, extinction coefficient have been evaluated using reflectance and absorbance data. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and photoluminescence properties of ZnO nanowire arrays

In this paper we report a chemical method named coordination reaction method to synthesize ZnO nanowire arreys. ZnO nanowires with the diameter about 80nm were successfully fabricated in the channels of the porous anodic alumina (PAA) template by the above coordination reaction method. The microstructures of ZnO/PAA assembly were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results showed that the ZnO nanowires can be uniformly assembled into the nanochannels of PAA template. The growth mechanism of ZnO nanowires and the conditions of the coordination reaction are discussed. Photoluminescence (PL) measurement shows that the ZnO/PAA assembly system has a blue emission band caused by the various defects of ZnO. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Microstructural Characterization of Electrosynthesized ZnTe Thin Films

Thin films of zinc telluride (ZnTe) were electrosynthesized on tin oxide coated conducting glass substrates at various bath temperatures. The deposited films were characterized by x‐ray diffraction (XRD) and scanning electron microscopy (SEM). The structure was found to be cubic with preferential orientation along (111) plane. X‐ray line profile analysis technique by the method of the variance has been used to evaluate the microstructural parameters. The variation of different microstructural parameters such as, crystallite size, RMS strain, dislocation density and stacking fault probability affecting the fraction of planes with film thickness and bath temperatures were studied. The experimental observations are discussed in detail.     

Synthesis of nanoflakes‐based self‐assembling crossed structure of stannous oxide and photocatalysis property

Self‐assembling nanoflakes‐based crossed architectures of stannous oxide (SnO) were successfully synthesized via template‐free hydrothermal growth method by using SnCl₂·2H₂O and KOH as precursors. Crystal structures, morphology, chemical composition and optical properties were examined by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), energy dispersive X‐ray analysis, and Raman spectroscopy, respectively. The results indicate that the as‐synthesized product belongs to tetragonal phase SnO with crossed morphology self‐assembled by nanoflakes. Furthermore, UV‐vis spectrophotometry was used to determine optical band gap of the SnO nanostructures and the direct band gap of 2.90 eV was obtained. The photocatalysis of the product has been evaluated with methyl orange and the high degradation ratio of 87% is obtained in 240 minutes under the measuring condition which is attributed to the wide band gap and large specific surface area of the nanoflakes‐based crossed SnO architectures. A possible growth mechanism is proposed in the end.