Showing papers by "Renchao Che published in 2011"
TL;DR: Experimental observations indicated that the BaTiO(3) nano-torus with an average diameter ranging from 50 to 100 nm was of tetragonal phases at room temperature, which might contribute more dissipation and scattering effects of the microwave.
Abstract: Uniform BaTiO3 nano-torus with either concave or epicenter holes were synthesized by a hydrothermal method. Experimental observations indicated that the BaTiO3 nano-torus with an average diameter ranging from 50 to 100 nm was of tetragonal phases at room temperature. The morphology of the BaTiO3 nano-torus depends on the shape of the original titanium dioxide precursor and reaction time. The microwave absorption properties of both the BaTiO3 nano-torus and the BaTiO3 solid nanoparticles were examined between 2–18 GHz microwave frequency bands. The maximum reflection loss of the BaTiO3 nano-torus reached −28.38 dB at 11.36 GHz, compared to that of −12.87 dB at 16.32 GHz of the BaTiO3 solid nanoparticles. The nearly 120% enhancement of the reflection loss in the range of 8–12 GHz was probably attributed to the hollow volume inside the BaTiO3 nano-torus which might contribute more dissipation and scattering effects of the microwave. Growth mechanisms of the BaTiO3 nano-torus were also investigated by changing both the reaction time from 0.5 h to 48 h and the reactants concentration ratio between Ba(OH)2·8H2O and titanium dioxide. Both an “in situ transformation” mechanism and a “dissolution-precipitation” growth mode were proposed.
100 citations
TL;DR: In this article, both Au and Au-CuO hierarchical heterostructured cubic microcages have been prepared using Cu2O cubes as sacrificial templates in aqueous solution.
Abstract: The controllable synthesis of hollow polyhedral hetero-structures composed of metallic and metallic–semiconductor nanograins has aroused great attention not only for the synthetic challenge, but also for the novel functions offered by their unique micro-/nanostructures. Herein, both Au and Au–CuO hierarchical heterostructured cubic microcages have been prepared using Cu2O cubes as sacrificial templates in aqueous solution. The micro-sized Au cubic cages are composed of Au nanograins about 20 nm in size with abundant pores inside the cage walls. Each individual Au–CuO hetero-structured cubic cage is assembled with both gold nanoparticles and CuO nanoneedles. A growth mechanism for the formation process of these delicate hierarchical cubic architectures is presented. Furthermore, the reflection loss (dB) spectra measured in the frequency range 2–18 GHz showed that the Au–CuO hollow hetero-structured cubic cages have an improved electromagnetic interference (EMI) shielding effectiveness (SE) compared to that of both Au hollow cubic microcages and conventional Au hollow microspheres. Moreover, these Au cages and Au–CuO cubic cages might find novel applications in sensing and catalysis due to their hierarchically assembled structures.
67 citations
TL;DR: In this article, an unusual extended and oriented wurtzite ZnS nanorods/nanowires have been successfully synthesized by a one-pot wet chemical method, and the products were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and UV-vis diffuse reflectance spectroscopy (DRS).
Abstract: Unusually extended and oriented wurtzite ZnS nanorods/nanowires have been successfully synthesized by a one-pot wet chemical method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and UV-vis diffuse reflectance spectroscopy (DRS). These nanorods and nanowires are well defined by stacking ZnS nanosheets layer-by-layer along the [0001] direction, and each layer of these nanorods (or nanowires) is a single crystalline ZnS wurtzite structure. A possible formation mechanism for the growth of the ZnS NRs has been proposed. More importantly, the layered ZnS nanorods/nanowires are confirmed to possess an extraordinary photocatalytic ability for the photodegradation of non-biodegradable brilliant red X-3B azo dye under UV-light irradiation.
34 citations
TL;DR: In this article, a facile and mild method was used to synthesize monodispersed ultrafine Bi 2 S 3 nanocrystals of ∼3nm, in which thioacetamide and bismuth oleate complex were used as the sulfur and Bismuth precursors, respectively.
17 citations