Gui-Hong Liao

Self-assembled 3D BiOCl hierarchitectures: tunable synthesis and characterization

3D hierarchitectures (HAs) of BiOCl composed of 2D nanosheets, which intercross with each other, have been successfully synthesized by a template-free solvothermal method at 160 °C for 12 h. The morphology and compositional characteristics of the 3D HAs were investigated by various techniques. On the basis of characterization results, the growth of such 3D HAs has been proposed as an Ostwald ripening process followed by self-assembly. The growth and self-assembly of BiOCl nanosheets could be readily tuned with the molar ratio of urea to BiCl3·5H2O, which brought different morphologies and microstructures to the final products. The specific surface area and porosity of the 3D hierarchitectured (HAd) BiOCl also were investigated by using nitrogen adsorption and desorption isotherms. UV–vis spectra reveal that the band gap energies of the 3D HAs can be tuned from 3.05 eV to 3.32 eV. The as-prepared 3D HAd BiOCl showed much higher photocatalytic activity than that of the reported in the literature, which was evaluated by the degradation of Rhodamine-B (RhB) dye under ultraviolet light irradiation.

Self-Assembled 3D Flower-Like Hierarchical β-Ni(OH)2 Hollow Architectures and their In Situ Thermal Conversion to NiO

Three-dimensional (3D) flower-like hierarchicalβ-Ni(OH)2hollow architectures were synthesized by a facile hydrothermal route. The as-obtained products were well characterized by XRD, SEM, TEM (HRTEM), SAED, and DSC-TGA. It was shown that the 3D flower-like hierarchicalβ-Ni(OH)2hollow architectures with a diameter of several micrometers are assembled from nanosheets with a thickness of 10–20 nm and a width of 0.5–2.5 μm. A rational mechanism of formation was proposed on the basis of a range of contrasting experiments. 3D flower-like hierarchical NiO hollow architectures with porous structure were obtained after thermal decomposition at appropriate temperatures. UV–Vis spectra reveal that the band gap of the as-synthesized NiO samples was about 3.57 eV, exhibiting obviously red shift compared with the bulk counterpart.

Synthesis and photocatalytic properties of core–shell structured α-Fe2O3@SnO2 shuttle-like nanocomposites

The core–shell structured α-Fe2O3@SnO2 shuttle-like nanocomposites were synthesized successfully by a simple solvothermal method. The structure and morphology were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). The results reveal that the diameter in the middle part and the length of the heteronanostructures are respectively 110 and 450 nm, and the thickness of the shell composed of 5 nm SnO2 nanoparticles is about 15 nm. The photocatalytic activities of the as-prepared α-Fe2O3@SnO2 core–shell shuttle-like nanocomposites were evaluated by the photocatalytic decolorization of a model pollutant Rhodamine-B (RhB) under ultraviolet light. The as-prepared core–shell shuttle-like nanocomposites showed much higher photocatalytic activity than that of α-Fe2O3 shuttle-like nanorods, SnO2 nanoparticles, and the mixture of α-Fe2O3 nanorods and SnO2 particles, which may be attributed to effective synergy between α-Fe2O3 and SnO2, and the special core–shell structures.

Porous Fluorine-Doped γ-Fe2O3 Hollow Spheres: Synthesis, Growth Mechanism, and Their Application in Photocatalysis

Porous fluorine-doped maghemite(γ-Fe2O3) hollow spheres have been prepared by facile route based on solvothermal reaction and sequential calcinations. The composition and morphology of the as-prepared samples were characterized by various techniques. The SEM and TEM results showed that the as-synthesized products exhibited a spherical morphology with porous hollow structures. Ultraviolet-visible (UV-vis) diffuse reflectance spectra display that the optical performance of γ-Fe2O3 products are related to their structure and the fluorine concentrations. The porous hollow structured fluorine-doped γ-Fe2O3 spheres exhibit ferromagnetic properties with relatively high saturation magnetization at room temperature. According to the experimental results, a formation mechanism of the fluorine-doped γ-Fe2O3 hollow spheres has been presented. Under UV light irradiation, the photocatalytic degradation activities of the as-synthesized fluorine-doped γ-Fe2O3 samples for RhB dye were 2-5 times higher than that of the undoped sample. The prepared fluorine-doped γ-Fe2O3 hollow spheres will also aroused great interest for their application in catalysis, separation technology, sensors, nanotechnology, and biomedical fields.

In situ synthesis of N-doped carbon nanotubes–BiOCl nanocomposites and their synergistic photocatalytic performance

N-Doped carbon nanotube–BiOCl (NCB) nanocomposites were prepared by an in situ growth strategy in liquid ethylene glycol (EG). The prepared samples were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic investigations showed that the 2-NCB nanocomposites loaded with 2.0 wt% N-doped carbon nanotubes (CNxNTs) possessed the highest rate constant, which is about 2.5, 3.7, and 1.5 times that of pure BiOCl 3D hierarchical structures, BiOCl/MWCNTs composites, and P25, respectively. The enhanced photocatalytic performance could be attributed to the beneficial microstructure, synergistic effects of coupled CNxNTs–BiOCl nanocomposites, and the high migration efficiency of the photogenerated electrons, which may effectively suppress the charge recombination.

Complex-Assisted Hydrothermal Synthesis and Optical Properties of CuO Nanorods

Copper monoxide (CuO) nanorods were successfully synthesized by complex-assisted hydrothermal route. The as-obtained CuO samples were well characterized by XRD, SEM, and TEM. TEM and SEM images showed that the particles have a uniform shape and narrow size distribution. HRTEM and SAED showed that the rod-like CuO nanoparticles were single crystalline monoclinic phase grown along the [110] direction. Optical property of the CuO nanorods was conducted by means of UV-vis spectrum, exhibiting obvious blue shift compared with the bulk counterpart.