Hanxiang Jia

Controllable fabrication of nanostructured copper compound on a Cu substrate by a one-step route

We report a one-step corrosion process to synthesize nanostructured CuO thin films at room temperature. The reaction time has great effect on the composition and microstructure of products to control the size and shape of the copper compound. X-ray diffraction studies showed the transformation of nanograins from Cu(OH)2 nanowires to flower-like CuO and to dispersed CuO nanosheets. The optical properties of CuO nanosheets were investigated by using UV-vis spectroscopy with considerable blue-shift in the optical band gap (Eg = 1.8 eV) due to the quantum confinement effect. Additionally, the photocatalytic activities of as-prepared copper compound films were determined by measuring the degradation of methyl blue (MB) to find out their potential application in waste water treatment. The photoluminescence (PL) spectrum showed both UV as well as visible emission peaks, indicating their good optical properties. Moreover, a reasonable growth mechanism for the formation of the CuO nanostructure is proposed by means of a scanning electron microscope (FESEM).

Controllable synthesis, characterization of ZnS nanostructured spheres

ZnS nanostructured spheres have been synthesized successfully without the assisted of surfactant, templates or capping agent via a facile hydrothermal method. Structural, morphological and optical characterization was fully performed. On the basis of characterization results, it was founded that the concentration of sulfur sources, hydrothermal reaction time and reaction temperature had an important effect on the formation of ZnS nanostructured spheres. The reason that reaction parameters are how to affect the formation of nanostructured spheres was investigated and discussed in detail. The formation mechanism of nanostructured spheres was innovatively proposed based on experimental results. The strong green PL emission of such structures would provide a potential application in novel luminescent devices. In addition, the route for the synthesis of ZnS nanostructures will be a promising way in the industrial application.

Facile synthesis of ZnS-ZnO nanocomposites for enhanced photocatalytic activity

Novel ZnS–ZnO nanocomposites were successfully synthesised via a facile thermal treatment of ZnS microstructure spheres. Microstructure, morphological and photocatalytic activity were fully investigated. X-ray diffraction patterns indicated that the ZnO was successfully decorated on the surface of ZnS. The microstructure of ZnS was transformed into nanocomposites after the formation of ZnO. The value of band gap decreased from 3.37 to 3.00 eV, which enhanced the light utilise efficiency. The ZnS–ZnO nanocomposites exhibited enhanced photocatalytic activity, compared with pristine ZnS. The enhancement of photocatalytic performance was attributed to the increased light absorption and effective separation of photogenerated electrons–holes.

Solution self-assembly of flower-like ZnO nanostructures with nanosheets and their optical properties

A uniform flower-like ZnO materials assembled by nanosheets have been synthesised on a large scale by a facile, cost efficient and room temperature solution route without the assistance of any substrate, template or seed layers. X-ray diffraction and field emission scanning electron microscopy were employed to characterise the phase composition and morphology of the samples, and ultraviolet–visible (UV-vis) diffuse reflectance spectrum and photoluminescence (PL) spectrum were used to analyse the optical properties of the samples. The flower-like ZnO materials with an average diameter of ∼2 μm are composed of interacted nanosheets with an average thickness of ∼5 nm. A reasonable growth mechanism that the formation of this kind of flower-like ZnO structures experienced a two-stage nucleation growth process was discussed. Based on the UV-vis diffuse reflectance spectrum, the band gap of hierarchical flower-like ZnO materials was calculated to be 3·27 eV. The PL spectrum suggests that flower-like ZnO materials only emit UV light and possess good optical properties.

The photocatalytic performance research of La2O3 modified TiO2 nanotube arrays

Since the environmental pollution is becoming more and more serious, TiO2 nanotube arrays, as a new kind of photocatalytic degradation materials have been widely researched and applied in our society. In order to enhance its photocatalytic performance, TiO2 nanotube arrays modified by La2O3 were successfully synthesized via an anodic oxidation method through dissolved La2O3 powder in the organic electrolyte. The photoelectron chemical performances of the composite nanotube arrays were characterized by FE-SEM, XRD, UV, and the photocatalytic activity was evaluated by photodegrading methylene blue which was treated as the target pollutants. The analytical results demonstrated that the La2O3 modified TiO2 nanotube arrays has a more significantly increased capability for photocatalytic properties than the pure TiO2 nanotube arrays, and the new concept was helpful to guide the synthesis of robust visible-light photocatalysts.