Search

CuO nanodendrites have been synthesized by a simple and novel hydrothermal method. Their morphology, structure, and composition have been also characterized. The results show that an as-prepared nanodendrite is composed of a main branch-like nanorod near upon a micrometre in length and about 100 nm in diameter and the sub-branch nanorods several hundred nanometres in length and 20–60 nm in diameter. The dendrite-like CuO nanostructures are of monoclinic phase and single crystalline in nature. The investigation of the hydrothermal process assisted by different quantities of ethylene glycol (EG) indicates that EG plays a critical role in the formation of dendrite-like CuO nanostructures. A possible mechanism for the formation of such CuO nanostructures is discussed. Furthermore, the correlation between the optical spectrum and the different morphologies of copper oxides nanomaterials is also discussed. [ABSTRACT FROM AUTHOR]

Flower-like Bi2S3 nanostructures consisting of nanorods with a lateral size of about 30 nm have been prepared via a thioglycolic acid (HSCH2COOH, TGA) assisted hydrothermal method. The x-ray diffraction (XRD) pattern shows that the obtained flower-like Bi2S3 nanostructures are of orthorhombic phase. High-resolution transmission electron microscopy (HRTEM) identifies that the flower-like Bi2S3 nanostructures are single crystalline in nature. It is believed that the sodium thiosulfate (STS) as the sulfur source could facilitate the formation of flower-like embryos and the TGA could enhance the anisotropic growth of Bi2S3 nanorods initiated from the embryos. STS and TGA play the key roles in the formation of flower-like Bi2S3 nanostructures during the hydrothermal process. [ABSTRACT FROM AUTHOR]

Abstract: The ZnO nanostructures have been synthesized by hydrothermal process in a dilute aqueous solution consisting of Zn(AC)2 and NaOH. X-ray diffraction (XRD) pattern indicates that the synthesized ZnO crystal is of hexagonal phase. By means of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE–SEM), it has been revealed that the ZnO nanoparticles, nanorods and nanotips sequentially occur along with the hydrothermal process, during which the concentration of Zn source is ever decreasing. The nanoparticles terminated with pyramids firstly generate at the early stage of hydrothermal process; subsequently, a number of seed-crystals branch on the pyramids, furthermore, the homo-epitaxy based on which along the <0001> direction results in the formation of nanorods; finally, due to the extremely low concentration of Zn source, instead of the continual elongation of the nanorods, the nanotips dispersively occur on the top flat plane of nanorods as a result of selective epitaxy. [Copyright &y& Elsevier]

Abstract: The CdS nanoparticles have been assembled into CdS nanorods and arrayed nanorod bundles by a thioglycolic acid (TGA) assisted hydrothermal processes using sodium sulfide (Na2S) and thiourea ((NH2)2CS) as the sulfur source, respectively. High-resolution transmission electron microscopy (HRTEM) shows that the CdS nanorods are single crystalline and the arrayed nanorod bundles are polycrystalline in nature. It is believed that the CdS nanorods were formed through the cluster-to-cluster oriented attachment mechanism, while the CdS nanorods bundles were formed through the particle-to-particle oriented attachment mechanism. In addition, the optical properties of CdS nanostructures were characterized by photoluminescence spectra (PL) and Raman spectroscopy. [Copyright &y& Elsevier]

Abstract: The disk-like, flower-like and nanorod flower-like ZnO nanostructures have been controllably fabricated by citric acid (CA) assisted hydrothermal process. All the ZnO nanostructures are hexagonal and single crystal in nature. The effects of the growth conditions such as temperature, pH value and the molar ratio of Zn2+ and CA on the morphology of ZnO nanostructures have also been investigated. It is considered that CA has a critical role in the formation of disk-like ZnO nanostructure. The pH value is the main factor to determine the anisotropic growth. The blue shift in the ZnO nanostructures is observed. Finally, the mechanism for CA assisted hydrothermal synthesis of the ZnO nanostructure is discussed. [Copyright &y& Elsevier]