Jia Ren

Heterostructured bismuth molybdate composite: preparation and improved photocatalytic activity under visible-light irradiation.

A heterostructured photocatalyst containing the same Bi, Mo, and O elements (Bi(3.64)Mo(0.36)O(6.55)/Bi(2)MoO(6)) was realized by a facile hydrothermal method. The heterostructured composite was characterized by powder X-ray diffraction, selected-area electron diffraction, scanning electron microscopy, and high-resolution electron microscopy. The Bi(3.64)Mo(0.36)O(6.55)/Bi(2)MoO(6) composite exhibited notable enhanced photocatalytic activity compared to Bi(2)MoO(6) or Bi(3.64)Mo(0.36)O(6.55) in the photocatalytic degradation of rhodamine B and phenol under visible-light irradiation. More interestingly, it is found that the heterostructured composite could mineralize organic substances into CO(2) efficiently. This study offered a clue for the design of an efficient photocatalyst in the application of environmental treatment.

A novel BiVO4 hierarchical nanostructure: controllable synthesis, growth mechanism, and application in photocatalysis

A novel BiVO4 hierarchical nanostructure assembled by nanorods was realized via a facile and additive-free solvothermal method. Based on the electron microscope observations, the growth of such architectures with “rod to dumbbell to sphere” transformation has been proposed as a crystal splitting growth process. Ethylene glycol (EG) instead of organic surfactant played an important dual role during the process. Different shapes were obtained by controlling the synthetic parameters. The as-prepared BiVO4 hierarchical nanostructures exhibited excellent visible-light-driven photocatalytic efficiency, which was increased to nearly 20 times than that of the products prepared by traditional solid-state reaction (SSR) and the nitrogen doped TiO2 (N–TiO2). Moreover, the photocatalyst could settle immediately, which is beneficial for the separation and recycle considering their future applications in waste water treatment.

A practical visible-light-driven Bi2WO6 nanofibrous mat prepared by electrospinning

An electrospinning technique was first developed to fabricate Bi2WO6 nanofibrous mat with excellent photoactivity under visible light. The nanofibers are made of single-crystalline Bi2WO6nanoparticles about 100 nm in size. The diameters of the nanofibers can be controlled by simply tuning the weight ratio of Bi2WO6 to poly(vinyl pyrrolidone) (PVP) (R). With the value of R increasing, the average diameter of the nanofibers was decreased. In addition to the favorable recycling characteristics, the mat with R = 2 exhibits higher photocatalytic activity in the decomposition of acetaldehyde (CH3CHO) and aqueous ammonia than that of the sample prepared by solid-state reaction (SSR) and the nanoparticles. Such an advantageous electrospinning route, which not only brings effective improvement in the photocatalytic activity of catalysts but also provides a solution to the separation problem for conventional catalysts that are small in size, is worth considering for the preparation of other photocatalysts.

General Strategy for a Large-Scale Fabric with Branched Nanofiber–Nanorod Hierarchical Heterostructure: Controllable Synthesis and Applications

The preparation and characterization of a branched nanofiber-nanorod hierarchical heterostructure fabric (TiO(2)/NiO, TiO(2)/ZnO, and TiO(2)/SnO(2)) are described. The nanomaterial was synthesized on a large scale by an inexpensive, generalizable, facile, and controllable approach by combining the electrospinning technique with a hydrothermal method. The controllable formation process and factors (assistance by hexamethylenetetramine and metal oxide nuclei) influencing the morphology of the branched hierarchical heterostructure are discussed. In addition, photocurrent and photocatalytic studies suggest that the branched hierarchical heterostructure fabric shows higher mobility of charge carriers and enhanced photocatalytic activity relative to a bare TiO(2) nanofibrous mat and other heterostructures under irradiation by light. This work demonstrates the possibility of growing branched heterostructure fabrics of various uniform, one-dimensional, functional metal oxide nanorods on a TiO(2) nanofibrous mat, which has a tunable morphology by changing the precursor. The study may open a new channel for building hierarchical heterostructure device fabrics with optical and catalytic properties, and allow the realization of a new class of nano-heterostructure devices.

Electrospun nanofibers of Bi-doped TiO2 with high photocatalytic activity under visible light irradiation.

Bi-doped TiO(2) nanofibers with different Bi content were firstly prepared by an electrospinning method. The as-prepared nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectra (PL), and UV-vis diffuse reflectance spectroscopy (DRS). The results indicated that Bi(3+) ions were successfully incorporated into TiO(2) and extended the absorption of TiO(2) into visible light region. The photocatalytic experiments showed that Bi-doped TiO(2) nanofibers exhibited higher activities than sole TiO(2) in the degradation of rhodamine B (RhB) and phenol under visible light irradiation (λ>420 nm), and 3% Bi:TiO(2) samples showed the highest photocatalytic activities.

Visible light responsive bismuth niobate photocatalyst: enhanced contaminant degradation and hydrogen generation

Niobate photocatalysts are of considerable interest in both contaminant degradation and H2 generation. However, the chemically inert nature limits the synthetic routes available to obtain these materials. Within this paper, single-crystalline Bi3NbO7 nanoparticles have been successfully synthesized by combining polymerized complex-assisted and hydrothermal methods. The reaction temperature was as low as 140 °C and the reaction time was only 12 h. The morphology, physical properties, and band structure of the sample was systematically investigated. The as-prepared Bi3NbO7 nanocrystallites in our experiment possessed higher photocatalytic activities in the photocatalytic degradation of both phenol and aqueous ammonia under visible-light irradiation than those of samples such as commercial Nb2O5, amorphous Nb2O5·nH2O, nitrogen-doped TiO2, P25 and Bi3NbO7 synthesized by solid solution routes. Moreover, the single-crystalline Bi3NbO7 nanoparticles were also able to efficiently evolve hydrogen from water under visible light, which provides a superior candidate for visible-light responsive photocatalysts.

Photocatalytic activity of silver vanadate with one-dimensional structure under fluorescent light.

One-dimensional β-AgVO(3) nanobelts (SVN) were realized by a facile hydrothermal method. It indicates the anisotropic crystallographic characteristics through the characterization. With the additive PEG, the sample was restrained in the one-dimensional preferential orientation (SV-P) effectively. The photocatalytic activity studies reveal that the photocatalyst β-AgVO(3) exhibits excellent photocatalytic activity in the inactivation of Escherichia coli under fluorescent light. In addition, it is found that the morphology has effect on the photocatalytic activity. The β-AgVO(3) photocatalyst with one-dimensional structure has the potential and promising application in bacterial disinfection indoor using fluorescent light.