Guangfang Li

Microwave synthesis of BiPO4 nanostructures and their morphology-dependent photocatalytic performances.

A facile and rapid microwave irradiation method was explored for the synthesis of bismuth phosphate (BiPO(4)) nanostructures with various morphologies and phases in different solvents. The BiPO(4) products were characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS). The effect of the solvents on the formation of the BiPO(4) nanostructures was discussed on the basis of experimental results. The different BiPO(4) nanostructures exhibited different optical properties, BET surface areas and photocatalytic activities on the degradation of methyl orange (MO) under UV and visible light irradiation. The experimental results suggested that the photocatalytic activity was closely relative with the crystalline phase and band gap of BiPO(4). Hexagonal BiPO(4) nanoparticles with narrow band gap showed the highest photocatalytic performance.

Template‐Free Fabrication of Bi2O3 and (BiO)2CO3 Nanotubes and Their Application in Water Treatment

Uniform bismuth oxide (Bi(2)O(3)) and bismuth subcarbonate ((BiO)(2)CO(3)) nanotubes were successfully synthesized by a facile solvothermal method without the need for any surfactants or templates. The synergistic effect of ethylene glycol (EG) and urea played a critical role in the formation of the tubular nanostructures. These Bi(2)O(3) and (BiO)(2)CO(3) nanotubes exhibited excellent Cr(VI)-removal capacity. Bi(2)O(3) nanotubes, with a maximum Cr(VI)-removal capacity of 79 mg g(-1), possessed high removal ability in a wide range of pH values (3-11). Moreover, Bi(2)O(3) and (BiO)(2)CO(3) nanotubes also displayed highly efficient photocatalytic activity for the degradation of RhB under visible-light irradiation. This work not only demonstrates a new and facile route for the fabrication of Bi(2)O(3) and (BiO)(2)CO(3) nanotubes, but also provides new promising adsorbents for the removal of heavy-metal ions and potential photocatalysts for environmental remediation.

BiOX (X=Cl, Br, I) nanostructures: mannitol-mediated microwave synthesis, visible light photocatalytic performance, and Cr(VI) removal capacity.

A facile microwave irradiation method has been successfully developed for the controllable fabrication of BiOX (X=Cl, Br, I) nanostructures in mannitol solution. The morphology and size of BiOX nanostructures could be readily tailored by adjusting the amount of halide, reaction precursor, and mannitol concentration. Mannitol molecule acts as both a capping agent and a cohesive agent in the formation of BiOX nanostructures. A possible two-stage formation mechanism was discussed based on the morphology evolution of BiOI nanostructures obtained in mannitol solution with different concentrations. The as-synthesized BiOX nanostructures exhibit much higher photocatalytic activities than that of commercial TiO2. In particular, flower-like BiOX hierarchical nanostructures display the best photocatalytic performance, which is mainly ascribed to their unique hierarchical structure, high BET surface area, and large band gap. Moreover, BiOX nanostructures also demonstrate superior Cr(VI) removal capacity. The Cr(VI) adsorption behavior was also analyzed by the Langmuir and Freundlich adsorption isotherms.

Size-tunable fabrication of multifunctional Bi2O3 porous nanospheres for photocatalysis, bacteria inactivation and template-synthesis

Multifunctional Bi2O3 porous nanospheres (PNs) with tunable size have been successfully synthesized via a facile solvothermal method. The obtained Bi2O3 porous nanospheres demonstrate outstanding performance in visible-light-driven photocatalysis for Cr(VI) and organic dye removal, inactivation of Gram-negative and Gram-positive bacteria, as well as template-synthesis for fabrication of bismuth-related hollow nanostructures.

Modification with Metallic Bismuth as Efficient Strategy for the Promotion of Photocatalysis: The Case of Bismuth Phosphate

A BiPO4 nanostructure modified with Bi nanoparticles rich in oxygen vacancies in the surface and subsurface was prepared through a one-pot solvothermal treatment utilizing the weak reductive ability of ethylene glycol (EG). The presence of Bi nanocrystals and oxygen vacancies is beneficial for the separation and consumption of photogenerated electrons and holes where Bi nanocrystals act as active sites for the formation of (.) OH and oxygen vacancies are active sites for (.) O2 (-) formation. The enhanced photocatalytic activity is ascribed to the synergistic effect of Bi nanocrystals and surface oxygen vacancies.

Large-scale synthesis of bismuth hollow nanospheres for highly efficient Cr(VI) removal

Bismuth hollow nanospheres were successfully synthesized via a facile solvothermal method and exhibit highly efficient Cr(VI) removal capacities in a wide pH range (2-11).

Hydrothermal synthesis of porous α-Fe2O3 nanostructures for highly efficient Cr(VI) removal

Porous α-Fe2O3 nanostructures with different morphologies, such as rod-like, sphere-like and cube-like nanostructures, were successfully synthesized via a facile hydrothermal method. The obtained products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and nitrogen adsorption. It was found that iron precursors played a crucial role in the formation of porous α-Fe2O3 nanostructures. The porous α-Fe2O3 nanorods possessed largest BET surface area and ideal pore distribution, as well as exhibited excellent Cr(VI) removal capacity and a fast adsorption rate in a wide pH range. Moreover, porous α-Fe2O3 nanorods also showed excellent adsorptive ability for organic dyes.

Thickness-tunable solvothermal synthesis of BiOCl nanosheets and their photosensitization catalytic performance

Bismuth oxychloride (BiOCl) nanosheets with tunable thickness were synthesized via a facile solvothermal method. The obtained BiOCl products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption. It was found that the metal ions (Fe3+, Co2+ and Na+) played a significant role in modulating the thickness of two-dimensional (2D) BiOCl nanostructures. Compared with commercial P25 and commercial BiOCl, the as-prepared BiOCl nanosheets exhibited superior activity for photosensitization degradation of organic dyes upon visible light irradiation. Furthermore, the photosensitization degradation activities were strongly correlated with the thickness of BiOCl nanosheets. The thinner nanosheets demonstrated a relatively high activity for the degradation of Rhodamine B (RhB). The enhanced photosensitization activities were ascribed to its low electron injection barrier and high electron mobility on the surface of BiOCl nanosheets, which was confirmed by transient photocurrent responses and electron impedance spectra of the samples.

Rhodamine B-sensitized BiOCl hierarchical nanostructure for methyl orange photodegradation

Loose-packed flower-like BiOCl hierarchical nanostructures (HNs) assembled by thin nanosheets were successfully synthesized via a facile solvothermal method. Based on the matchability analysis of band structure of BiOCl and the molecular orbitals of the dyes, the RhB dye-sensitized heterogeneous BiOCl HNs system was established for MO degradation under visible light irradiation. The mechanism of MO degradation over RhB-sensitized BiOCl was also discussed according to the photocurrent and photoluminescence results. It was found that MO degradation efficiency over RhB-sensitized BiOCl HNs was obviously improved due to the generation of superoxide radicals (˙O2−) through the reduction of surface-adsorbed O2 molecules by the injected electrons on the conduction band of BiOCl HNs from the excited RhB molecules. This work may provide insight on better understanding the organic dye photodegradation process in RhB dye-sensitized BiOCl heterogeneous systems and explore a dye-sensitized semiconductor photocatalyst strategy for environmental remediation.