Search

Supported nanostructured photocatalysis is considered to be a sustainable and promising method for water pollution photodegradation applications due to its fascinating features, including a high surface area, stability against aggregation, and easy handling and recovery. However, the preparation and morphological control of the supported nanostructured photocatalyst remains a challenge. Herein, a one-step hydrothermal method is proposed to fabricate the supported vertically aligned ZnO nanosheet arrays based on aluminum foil. The morphologically controlled growth of the supported ZnO nanosheet arrays on a large scale was achieved, and the effects of hydrothermal temperature on morphologic, structural, optical, and photocatalytic properties were observed. The results reveal that the surface area and thickness of the nanosheet increase simultaneously with the increase in the hydrothermal temperature. The increase in the surface area enhances the photocatalytic activity by providing more active sites, while the increase in the thickness reduces the charge transfer and thus decreases the photocatalytic activity. The influence competition between the area increasing and thickness increasing of the ZnO nanosheet results in the nonlinear dependence between photocatalytic activity and hydrothermal temperature. By optimizing the hydrothermal growth temperature, as fabricated and supported ZnO nanosheet arrays grown at 110 °C have struck a balance between the increase in surface area and thickness, it exhibits efficient photodegradation, facile fabrication, high recyclability, and improved durability. The RhB photodegradation efficiency of optimized and grown ZnO nanosheet arrays increased by more than four times that of the unoptimized structure. With 10 cm2 of as-fabricated ZnO nanosheet arrays, the degradation ratio of 10 mg/L MO, MB, OFL, and NOR was 85%, 51%, 58%, and 71% under UV irradiation (365 nm, 20 mW/cm2) for 60 min. All the target pollutant solutions were almost completely degraded under UV irradiation for 180 min. This work offers a facile way for the fabrication and morphological control of the supported nanostructured photocatalyst with excellent photodegradation properties and has significant implications in the practical application of the supported nanostructured photocatalyst for water pollution photodegradation.

3D ZnO hierarchical nanostructures have been successfully synthesized by heating aqueous solutions with a facile surfactants assisted hydrothermal route. The morphology depended on the different surfactants (ionic surfactant: SDS, CTAB and nonionic surfactant: PEG400, PVP) in aqueous solutions. According to the result of SEM, the four products with uniform particle size presented different morphologies. The possible growth mechanism was discussed from three aspects which were nucleation, growth and self-assembly processes respectively. The photocatalytic results indicated that the product grown in the solution with PVP exhibited a significantly high photocatalytic activity and good stability in the processes of cycling degradation of methylene blue. This was mainly due to the special morphology, uniform size and good stability.

Flower-like hierarchical zinc oxide nanostructures have been successfully synthesized by a facile and template-free hydrothermal method from zinc acetate (Zn(AC)2) and potassium hydroxide (KOH) only. Furthermore, the effects of alkaline mineralizer type on product synthesis by hydrothermal processing have been studied. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscope, UV–vis spectrophotometry and Raman-scattering spectroscopy. When the type of mineralizer was KOH, the shape of ZnO sample has presented flower-like hierarchical nanostructures with diameters of 2–4 μm. Photocatalytic activity of the hierarchical ZnO nanostructures was evaluated by the degradation of methylene blue (MB) under UV light illumination. The as-prepared ZnO nanostructures exhibited a significantly enhanced photocatalytic activity than commercial ZnO. This was mainly attributed to the unique morphology and higher surface area.

A new multifunctional compound containing hierarchical microspheres of Fe3O4@SiO2@MoS2/g-C3N4 (FSMG) was created. The microspheres comprised Fe3O4@SiO2 as a magnetic component and a heterostructure of MoS2/g-C3N4 as an outer shell, and both elements are compounded by an effective and applicable method and can be used in photocatalytic applications. Highly efficient separation of the photodriven pairs of electron/hole pairs (e–/h+) was exhibited with the as-synthesized FSMG structures under visible light. The photocatalytic activities of Fe3O4@SiO2@MoS2, g-C3N4, and FSMG are assessed by surveying the hydrogen (H2) production and rhodamine B (RhB) photodegradation from water. These contrasting studies show that microspheres of FSMG show promising visible-light-induced photocatalytic activity and exhibit 1.99-fold and 3.38-fold increased activity over that of Fe3O4@SiO2@MoS2 and g-C3N4 mechanisms, respectively, in RhB degradation and a 4.13-fold and 11.09-fold increase in H2 production from water, respective...

SnO2 nanostructures were prepared successfully through a template-free and surfactant-free hydrothermal method. The prepared SnO2 nanostructures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectra and UV–vis absorption spectra. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. Furthermore, the possible growth and photodegradation mechanism of the as-prepared sample were also briefly discussed.

In this study, the flower-like ZnO nanostructures have been fabricated using zinc chloride and potassium hydroxide as precursors by sonochemical technique. The as-prepared ZnO nanostructures were characterized by SEM, XRD, Fourier Transform Infrared Spectroscopy (FTIR), Raman spectra and UV–vis spectroscopy. The results indicated that the synthesized zinc oxide posses a flower shape with diameters in the range of 4–6 μm. Meanwhile, every single flower is composed of needle-like crystals of 200–300 nm in diameter irradiated from the center. The morphologies of the obtained product at different sonochemical time were experimentally studied. The formation mechanism is discussed in detail. Additionally, photocatalytic activity of the prepared ZnO sample was evaluated by the degradation of methylene blue under UV irradiation.

The undoped and Zn-doped SnO2 products have been synthesized by a solvothermal method. With the Zn doping concentration changing from 0 to 20 mol%, the SnO2 morphology evolved from aggregated nanoprisms into hierarchical porous spheres. The products were characterized by x-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, selected area electron diffraction, UV-Vis absorption spectra, and photoluminescence spectra analysis. The results showed that Zn doping concentration significantly influenced on the microstructure, size, morphology, and optical property of the SnO2 products. Furthermore, the influence of the doping effect on the photocatalytic performance of the as-prepared SnO2 products was compared. The results revealed that 20 mol% Zn-doped SnO2 with hierarchical porous spheres exhibited excellent efficiency of photocatalytic activity, which could be attributed to their abundant oxygen vacancies, large specific surface area, and porous structure.

SnO2 nanosheets with sizes around 1 μm and thickness around 30 nm have been synthesized by a template-free hydrothermal method. With the addition of urea, SnO2 hollow microspheres with diameters of about 1 μm and shell thickness of about 200 nm were also prepared. The structures, morphologies, and optical properties of the as-prepared samples were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction, Raman spectroscopy, and ultraviolet-visible absorption spectrophotometry. The possible mechanisms for the growth of these SnO2 nanostructures were tentatively proposed based on controlled experiments. Moreover, photocatalytic investigations revealed that the as-prepared SnO2 samples possessed good photocatalytic activity in the degradation of rhodamine B.

Novel walnut-like SnO2spheres have been synthesized using a one-step hydrothermal reaction with SnCl2·2H2O and KOH as raw materials. The morphology, microstructure, and optical properties of the products were characterized by X-ray powder diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and ultraviolet-visible (UV-Vis) absorption spectroscopy. The detailed studies revealed that these synthesized spheres are highly monodisperse and have a uniform size of approximately 250 nm. Photocatalytic activity of the prepared SnO2spheres was evaluated by the degradation of methylene orange. The synthesized SnO2spheres exhibited excellent photocatalytic degradation. In addition, a possible formation mechanism of the walnut-like nanostructures was proposed based on reaction time-dependent experiments.

Flower-like ZnO nanostructures have been successfully synthesized via a facile and template-free sonochemical method, using zinc acetate and potassium hydroxide as reactants only. The as-synthesized flower-like ZnO nanostructures were composed of nanorods with the width of ∼ 300 – 400 nm and the length of ∼ 2 – 3 μm . The structures, morphologies and optical properties of the as-prepared products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, UV-Vis spectrophotometry and Raman-scattering spectroscopy. A plausible formation mechanism of flower-like ZnO nanostructures was studied by SEM which monitors an intermediate morphology transformation of the product at the different ultrasonic time ( t = 80 , 90 , 95 , 105 , and 120 min ).

In this work, Co-doped ZnO nanofibers have been fabricated successfully by an electrospinning technique. The as-prepared nanofibers are characterized by themogravimetric analysis (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectra and photoluminescence spectroscopy (PL). Results have showed that a wurtzite ZnO nanofibers were obtained and the PL spectrum showed a red-shift by 10 nm due to narrowing of the ZnO band gap (∼3.29 eV) as a result of Co doping. Meanwhile, Raman scattering spectra exhibited an unusual peak at 540 cm−1.

ZnO microstructures were prepared by a simple microwave-assisted solution phase approach in the present of cetyltrimethylammonium bromide (CTAB). The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy. The influence of reaction time and the molar of CTAB on the morphologies and sizes of the products has been investigated. A possible growth mechanism of ZnO microstructures has also been discussed.

In this work, monodispersed silver nanoparticles decorated SiO 2 nanofibers were synthesized by electrospinning method, followed by thermal treatment at 600 °C. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the composite nanofibers. Accordingly, the detailed formation mechanism of SiO 2 /Ag composite nanofibers was discussed. Furthermore, an excellent catalytic activity of SiO 2 /Ag composite fibers was observed by a degradation reaction of methyl orange (MO) dye.

ZnO thin films with (002) orientation have been deposited on Si(100) substrate by radio frequency (RF) magnetron sputtering technique. The influence of RF power and oxygen ratio on the the grain size-, the residual stress and optical properties was investigated by X-ray diffraction, transmission spectra and photoluminescence spectra. The results show that the ZnO film deposited with sputtering power (100W) and oxygen ratio(60%), can obtain its best c-axis orientation and crystallization and that tension stress of the film reaches the lowest, and a strong UV photoluminescence(PL) peak and a weak blue emission peak were observed.

In the research of detecting extinction ratio of polarimeter, some significant characters are discovered. One polaroid has perfect extinction ratio in the visible, but its extinction ratio becomes weak in near infrared (NIR) region, and the transmittance of a pair of vertical polaroid becomes strong in NIR region. This phenomenon has been found in several other polaroids as well. The transmittance increases greatly in NIR even if the crystal Glan-Taylor prism polarimeter with good polarization is used. The extinction ratio of the polaroid changes from 3:100 in visible to 98:100 in NIR. More experiments have shown that the weakening of extinction ratio and the enhancement of transmittance of a pair of vertical polaroid in NIR are closely associated with the intensity of incident light. When the light intensity increases, the effect becomes clearer. The transmittance exceeds the theoretical results from classical physical optics, reaching 98%. Our results provide two aspects of applications. First, because the extinction ratio of the polaroid is related to the wavelength of incident light, the polaroid can be used in definite spectral range. Second, a pair of vertical polaroid can perfectly filter the visible light, while making NIR light transmit. This research result can provide some conveniences at IR spectrum, IR photography, IR imaging and IR detection.