Yongjie Zhan

A simple route to hydroxyapatite nanofibers

Abstract Hydroxyapatite nanofibers were prepared by a simple route at ambient conditions, by which the reaction of calcium chloride and sodium phosphate took place. The length and diameter were 160–220 and 5 nm, respectively. The microstructure of the resultant nanofibers was studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transmission infrared spectrometer (FTIR) and Raman spectra. It has been found that hydroxyapatite nanofibers have high crystalline and fairly pure phase.

One-step, solid-state reaction to the synthesis of copper oxide nanorods in the presence of a suitable surfactant

A novel and simple one-step, solid-state reaction in the presence of a suitable surfactant has been developed to synthesize uniform copper oxide nanorods with average diameters of ca. 8 nm and lengths of up to 400 nm.

Growth and mechanism of titania nanowires

Abstract Anatase and rutile-phase titania nanowires have been prepared via an efficient molten salt-assisted and novel pyrolysis route, respectively. The growth of anatase nanowires is parallel to [010] direction. The anatase titanium oxide nanowires are obtained by exchange reaction between Na2TiO3 and HCl, whereas the formation of rutile titania nanowires is conventional vapor–liquid–solid growth mechanism.

Synthesis of NiO nanowires by an oxidation route

Abstract In this letter, we report NiO nanowires synthesized by means of oxidation route. NiS prepared by microemulsion method was used as precursor compound. NiO nanowires grew in molten NaCl and were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAD) techniques. The results indicate that these nanowires with diameters about 40–100 nm and lengths up to 10 μm have fine crystallinity and large aspect ratios. Suitable precursor and molten salt conditions play an important role in obtaining the final product.

A novel and simple one-step solid-state reaction for the synthesis of PbS nanoparticles in the presence of a suitable surfactant

Abstract A novel and simple one-step solid-state reaction in the presence of a suitable surfactant has been developed. We have synthesized PbS nanoparticles with the diameters of ca. 10–15 nm by using this method. The PbS nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV-VIS optical absorption, and X-ray photoelectron spectrum (XPS). The roles of surfactant C 18 H 37 O(CH 2 CH 2 O) 10 H (abbreviated as C 18 EO 10 ) in the forming of PbS nanoparticles were discussed, and the results indicated that the surfactant C 18 EO 10 played an important role in the preparation of PbS nanoparticles.

Preparation of SnO2 nanorods by annealing SnO2 powder in NaCl flux

SnO2 nanorods having the rutile structure have been prepared by annealing fine SnO2 powder in a NaCl flux. The starting SnO2 powder, the NaCl flux, and surfactant NP9 were mixed and heated at 800 °C for 2.5 h. The nanorods have diameters of ca. 20–40 nm and lengths of up to 1 μm. High-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) showed that the nanorods were well-crystallized with a rutile structure. The structure features and chemical composition of the as-prepared nanorods were analyzed by XRD, TEM, HRTEM, SAED, EDS and FTIR. A possible growth mechanism of the nanorods was described by the studies of the formation of nanorods with comparative experiments. The effects of NaCl and NP9 are discussed in detail.

Synthesis of cadmium oxide nanowires by calcining precursors prepared in a novel inverse microemulsion

The semiconductor nanowires are of special interest for their electronic, optical and conductive properties [1, 2]. Many methods have been developed to prepare semiconductor nanowires [3–5]. However, complicated apparatus, complex process control and special conditions may be required for these approaches. Here a new method for the preparation of cadmium oxide nanowires by calcining precursor powders containing cadmium carbonate, sodium chloride and potassium nitrate, previously prepared in a novel inverse microemulsion is reported. The method is distinguished by its simplicity of the apparatus used and the high efficiency of crystal growth. One of the simple preparation methods for a complex oxide is molten salt synthesis (MSS) [6], in which molten salts are used as solvents. In this method, the synthesis temperature and time are the process parameters, which lead to different results. Changes in the amount and type of salt can result in differences in powder characteristics because they are responsible for the reaction and growth environments. There are several requirements for the selection of the salt [6]. First, the melting point of the salt should be low and appropriate for the synthesis of the required phase; second, the salt should have sufficient aqueous solubility to enable it to be eliminated easily by simple washing after synthesis. Third, there should be no side reaction between the salt and the constituent oxides, which could result in undesirable second phases. Transparent conducting oxides have been studied extensively because of their importance in the fabrication of optoelectronic devices [7, 8]. Among the conducting oxides, cadmium oxide, a II–VI, n-type semiconductor, is one of the promising candidates for optoelectronic applications such as solar cells [9, 10], photo transistors [11], photo diodes [12] and transparent electrodes [13]. Applications of cadmium oxide have recently been extended to gas sensors [14] because of its ionic nature coupled with wide band gap (direct band gap of approximately 2.5 eV and indirect one experimentally found at 1.98 eV [15, 16]).

Synthesis of CoO fibers in pyrolytic process

Abstract Cobalt oxide fibers were synthesized by a simple pyrolytic process in which cobalt sulfate was used as precursor, and molten NaCl was used to provide a suitable liquid growth circumstance. X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and scanning electron microscopy (SEM) show that these micron-sized fibers were CoO with big aspect ratios and good yield. Their diameters were about 1–3 μm and lengths up to several hundred millimeters. The species of the precursors play an important role in deciding the final morphology of the products.