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1.
A novel chrysanthemum-shaped monocline ZnWO 4 photocatalyst was synthesized by microwave-assisted hydrothermal method with Na 2WO 4·2H 2O and Zn(NO 3) 2·6H 2O as raw materials at different reaction temperatures. The prepared ZnWO 4 photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy, Photoluminescence spectrum (PL) and UV–Vis absorption spectrum (UV–Vis). The photocatalytic property of the prepared chrysanthemum-shaped monocline ZnWO 4 photocatalyst was evaluated by the degradation of Rhodamine B (RhB) in aqueous solution. The effects of reaction temperature on the photocatalytic degradation efficiency of RhB were investigated. The results indicated that the chrysanthemum-shaped monocline ZnWO 4 photocatalyst is prepared by foliated powders with the sizes of about 30 nm and 500 nm respectively at 160 and 220 °C. The PL relative intensity of prepared ZnWO 4 photocatalyst is apparently intensifying with increasing temperature. The photocatalytic property decreases with the increasing recombination probability of the excited electrons and holes. The chrysanthemum-shaped monocline ZnWO 4 photocatalyst prepared at 160 °C possesses the best photocatalytic property, and the degradation efficiency of RhB at 180 min UV-light irradiation is achieved 75 %. The ZnWO 4 has good reusability property on degradation of RhB and the degradation rate is still higher than 65 % after three cycles. 相似文献
2.
Magnetically recoverable Fe 3O 4/BiOCl nanocomposite photocatalysts were fabricated by a simple chemical coprecipitation method at room temperature. The amount of Fe 3O 4 incorporated into BiOCl was varied from 0 to 20 wt%. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, UV–Vis diffuse reflectance spectroscopy, and vibrating sample magnetometer. The obtained results show that the as-synthesized samples mainly contain both crystalline phases (Fe 3O 4 and BiOCl) and are composed of flower-like nanostructures. Compared to UV light-responsive BiOCl, all the nanocomposite photocatalysts show a strong light absorbance in the range of 250–800 nm, demonstrating that the Fe 3O 4/BiOCl nanocomposites can respond to visible as well as UV light. Moreover, visible light absorbance was increased with the increase in the Fe 3O 4 amount in the composite. The photocatalytic activity of nanocomposite photocatalysts was evaluated by the photodegradation of Rhodamine B (RhB) over the samples under visible light irradiation. The 10 wt% Fe 3O 4/BiOCl nanocomposite photocatalyst shows the highest photocatalytic efficiency among the samples. The Fe 3O 4/BiOCl nanocomposite photocatalyst was stable under visible light irradiation to efficiently degrade RhB molecules after five cycles and could be easily recovered with a magnet after each cycle. 相似文献
3.
以硝酸铟作为前驱体,在蒸馏水和乙二胺的混合溶剂中制备出了InOOH纳米晶,详细地考察了反应溶剂及温度对终产物的影响。利用X射线粉末衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)、扫描电子显微镜(SEM)和透射电镜(TEM)对样品的晶相结构、光吸收性质及其形貌进行了详细的表征。考察了样品在紫外光下及可见光下对液相中的染料罗丹明B(RhB)的光催化降解性能。发现InOOH在紫外光下可以彻底分解RhB,而在可见光下只能使RhB脱色。InOOH在紫外光和可见光下对RhB的分解遵循两种不同的反应机制。 相似文献
4.
Multiferroic BiFeO 3–(Na 0.5Bi 0.5)TiO 3 (BFO–NBT) nanopowders were successfully synthesized by a sol–gel method, and the visible-light photocatalytic and magnetic properties of BFO–NBT nanopowders were investigated. X-ray diffraction results indicated that the adding of NBT and the excess of natrium source could suppress the formation of secondary phases and made it easier to obtain single perovskite phase. High photoactivity of this catalyst for Rhodamine B (RhB) degradation under visible-light irradiation was detected, which is due to narrow band gap energy of 2.08 eV, higher surface area and pure phase compounds with no or less amounts of impurities. The BFO–NBT nanopowders showed a weak ferromagnetic order at room temperature, which should be attributed to the size-confinement effects of the nanostructures. It is suggested that BFO–NBT is a kind of new narrow band gap semiconductor visible-light photocatalyst with broad application prospects, in addition to potential applications for novel magnetoelectric devices. 相似文献
5.
Nitrogen-modified cobalt-doped TiO 2 materials were successfully prepared via a modified sol–gel method. The structure and properties of the catalysts were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM, ultraviolet–visible light diffuse reflectance spectra (UV–Vis DRS), N 2 adsorption–desorption isotherms, and energy-dispersive X-ray spectroscopy. The XRD patterns of the pure and co-doped TiO 2 samples indicate that the predominant phase was anatase. The average grain size obtained from TEM was approximately 10 nm. The Brunauer–Emmett–Teller analysis results indicate that the specific surface area was 77.7 m 2 g ?1. The UV–Vis DRS results for the co-doped sample reveal an absorption edge that had been red-shifted to 500 nm. The photocatalytic activities of the samples were evaluated through photodegradation of papermaking wastewater under UV and visible light irradiation. Compared with the cobalt-doped TiO 2 sample and Degussa P25, the 3 mol% N-doped mesoporous N/Co-TiO 2 photocatalyst exhibited the highest photocatalytic activity, which can be ascribed to the synergistic effect of the N and Co co-doping. 相似文献
6.
This present investigation focused on novel p-type bismuth ferrite (BiFeO3)/n-type tin sulfide (SnS2) heterostructure photocatalyst has been favorably attained via a facile two-step process followed by co-precipitation approach for enhances the photocatalytic activity through the degradation of Methylene Blue (MB) and Rhodamine B (RhB) organic dyes under visible-light illumination. Structural, optical, and photocatalytic behavior of the prepared BiFeO3 and BiFeO3/SnS2 photocatalysts are carefully explored. The photocatalytic efficiency of BiFeO3/SnS2 nanocatalyst was calculated to be 83%, 78% for MB and RhB, respectively, within 120 min illumination whereas the pure BiFeO3 nanoparticle was 58% and 56% for MB and RhB. This prominent enhancement of visible light photocatalytic activity can be ascribed to the separation as well as the transfer of photogenerated charge carriers, successful exploitation of visible light absorption and donates the enlarged number of photocatalytic active sites by the formation of BiFeO3/SnS2 p-n heterojunction. 相似文献
7.
Visible‐light‐driven plasmonic photocatalyst Ag‐TiO 2 nanocomposite hollow spheres are prepared by a template‐free chemically‐induced self‐transformation strategy under microwave‐hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, N 2 adsorption‐desorption isotherms, X‐ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of ?OH radicals on the surface of visible‐light illuminated TiO 2 was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as‐prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible‐light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO 2 hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag‐TiO 2 nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible‐light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO 2 and commercial Degussa P25 (P25) powders. Especially, the as‐prepared Ag‐TiO 2 nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium ( R ) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2. 相似文献
8.
3D BiOBr flower-microspheres decorated with small amount (0.02–0.5 wt%) of Pt nanoparticles were successfully prepared via new electrostatic-adsorption-assisted light-reduction route. The as-prepared samples were characterized by XRD, SEM, HRTEM, EDS, XPS, UV–Vis DRS, PL, and photocurrent measurements. The photocatalytic activities were tested through the photocatalytic degradation of Bisphenol A (BPA) under visible light (420 nm?<? λ?<?680 nm) and simulated sunlight (320 nm?<? λ?<?680 nm) irradiation. The results indicate that Pt loading do not change the structural morphologies and particle sizes of BiOBr flower-microspheres, but there exists an enhanced photocurrent effect, greatly achieving the highly efficient photocatalytic activity of BiOBr under visible-light and simulated sunlight irradiation. 0.2 wt% Pt/BiOBr sample reveals the highest photocatalytic activity for the degradation on BPA with almost 92% under 10 min, much better than pure BiOBr and (P25) TiO 2. The presence of synergistic effect between Pt 4+ and Pt 0 has vital impact on the electron capture and transfer from the semiconductor to noble metal, preventing the fast electron/hole recombination and participating in the multi-electron reduction of O 2, and, consequently, achieving the formation of effective photocatalytic active species. Our findings should provide the fundamental data for making further research efforts in the hot topic on the monatomic Pt-modified photocatalyst systems. 相似文献
9.
以TiCl4为钛源,离子液体-水为混合溶剂,采用液相水解-沉淀法制得浅黄色的N、F共掺杂宽光域响应多孔TiO2光催化剂(TiONF).以苯酚为模型物,考察了TiONF在紫外光区、可见光区及太阳光下催化活性.采用X射线光电子能谱(XPS)、紫外-可见漫反射光谱(DRS)、透射电镜(TEM)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱及低温N2吸附-脱附等技术对TiONF的结构进行表征.结果表明,在离子液体-水混合介质中合成适量N、F共掺杂的TiO2在紫外光区、可见光区及太阳光下均表现出较高的活性,且高于纯水介质中合成TiONF的活性.离子液体-水混合介质有利于N、F进入TiO2晶格中;N、F共掺杂后在TiO2表面生成Ti―O―N键,形成新的能级结构,使催化剂的吸收红移至450-530nm,诱发TiO2可见光催化活性;同时,N、F共掺杂提高了TiO2表面羟基数量;还提高了TiO2相转变温度,减缓了相转变速率.另外,在离子液体-水混合介质中合成的TiONF较纯水介质中合成的TiONF粒子小、分散性好、比表面积大. 相似文献
10.
Silver orthophosphate-graphene nanosheets composite (Ag 3PO 4-GNs) has been fabricated using a facile hydrothermal method. The Ag 3PO 4-GNs were characterized using XRD, UV–vis DRS and SEM. The photocatalytic activity of Ag 3PO 4-GNs was evaluated by photocatalytic decolorization of dye aqueous solutions under simulated solar light irradiation. It was observed that Ag 3PO 4 nanoparticles in Ag 3PO 4-GNs were attached on the surface of graphene nanosheets.The introduction of graphene nanosheets enhanced remarkably the visible light absorption region of Ag 3PO 4-GNs compared with bare Ag 3PO 4. The photocatalytic activity of Ag 3PO 4-GNs is nearly twice as high as that of the pure Ag 3PO 4. The removal efficiency can reach more than 90 % by Ag 3PO 4-GNs under simulated solar light irradiation within 25 min, which might mainly be attributed to high adsorption capacity, extended light absorption range and efficient charge separation. After irradiation for 60 min, 84.70 % TOC mineralization was achieved by Ag 3PO 4-GNs. Based on the results of detection of active species, the direct oxidization of dye pollutants in aqueous solution by holes takes a major role in the whole decolorization process by Ag 3PO 4-GNs. As a result, Ag 3PO 4-GNs with the high photocatalytic activity are proven to be an excellent light photocatalyst for potentially scalable removal of dyes in aqueous solutions and other environmental remediation under simulated solar light irradiation. 相似文献
11.
ZnFe 2O 4 nanoparticles sensitized by C-modified TiO 2 hybrids (ZnFe 2O 4–TiO 2/C) were successfully prepared by a feasible method. The ZnFe 2O 4 nanoparticles were prepared by mechanical alloying and annealing. The residual organic compounds in the synthetic process of TiO 2 were selected as the carbon source. The as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, X-ray fluorescence, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible light diffuse reflectance spectroscopy (UV–Vis) and N 2 adsorption–desorption analysis. The photocatalytic activity of the photocatalysts was measured by degradation of methyl orange under ultraviolet (UV) light and simulated solar irradiation, respectively. The results show that the carbon did not enter the TiO 2 lattice but adhered to the surface of TiO 2. The photocatalytic activity of the as-prepared C-modified TiO 2 (TiO 2/C) improved both under UV and simulated solar light irradiation, but the improvement was not dramatic. Introduction of ZnFe 2O 4 into the TiO 2/C could enhance the absorption spectrum range. The ZnFe 2O 4–TiO 2/C hybrids exhibited a higher photocatalytic activity both than that of the pure TiO 2 and TiO 2/C under either UV or simulated solar light irradiation. The complex synergistic effect plays an important role in improving the photocatalytic performance of ZnFe 2O 4–TiO 2/C composites. The optimum photocatalytic performance was obtained from the ZnFe 2O 4(0.8 wt%)–TiO 2/C sample. 相似文献
12.
Bare TiO 2 and Cu-doped TiO 2 nanoparticles with different nominal doping amounts of Cu ranging from of 0.5 to 5.0 mol% were synthesized using the modified sol–gel method. The samples were physically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller-specific surface area, UV–Vis diffuse reflectance spectroscopy, zeta potential, X-ray photoelectron spectroscopy, inductively coupled plasma, and photoluminescence techniques. The Cu-doped TiO 2 exhibited good photocatalytic activity in mineralization of oxalic acid and formic acid under visible light irradiation. Photomineralization of oxalic and formic acids under visible light irradiation revealed greatly enhanced photoactivity exhibited by the 2.0 mol% Cu-doped TiO 2 photocatalyst compared to bare TiO 2 . The enhanced photocatalytic performance arises from copper ion doping in the TiO 2 structure, leading to an extended photoresponsive range, enhanced photogenerated charge separation, and transportation efficiency. 相似文献
13.
Uniform Bi 2WO 6 pancakes were prepared via a solvothermal route in a solvent mixture of glycerol (Gly) and water ( V/ V = 1). A variety of techniques including scanning electron microscopy, transmission electron micrographs, X-ray powder diffraction, Brunauer–Emmett–Teller, FT-IR spectra, and UV–Vis diffuse reflectance spectra, were employed to characterize the structure and properties of the as-obtained Bi 2WO 6. It was found that Bi 2WO 6 pancakes showed prominent photocatalytic performance for the degradation of rhodamine B (RhB) under visible light ( λ ≥ 420 nm) irradiation, which can be attributed to its good crystallization, large surface area, unique morphology and structural features. 相似文献
14.
采用电化学方法制备Ag@AgI/Ni表面等离子体薄膜催化剂,使用扫描电镜(SEM),X射线衍射(XRD)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶体结构、光谱特性以及能带结构进行分析表征,在模拟太阳光照射下,把罗丹明B作为模拟污染物对薄膜的光催化活性与稳定性进行评价,采用向反应体系中加入活性物种捕获剂的方法对薄膜光催化机理进行探究。结果表明:最佳工艺下制备的Ag@AgI/Ni薄膜表面是由附着少量Ag粒子的AgI纳米晶构成。薄膜具有显著的表面等离子共振作用、优异的光催化活性和突出的光催化稳定性。光催化反应60 min,薄膜对罗丹明B的降解率(81.1%)是AgI/Ni薄膜的1.35倍,是TiO 2(P25)/ITO薄膜的1.61倍。在薄膜光催化活性基本保持不变的前提下可循环使用5次。薄膜表面纳米Ag的等离子共振对光阴极反应的活化是光催化性能提高的重要原因。提出了薄膜光催化降解罗丹明B的反应机理。 相似文献
15.
A AgBr/DyVO 4 composite photocatalyst was synthesized by a hydrothermal method for the first time. The physical and chemical structure and optical properties of the composite catalysts were investigated by XRD, XPS, SEM, TEM and UV–Vis. It was found that the prepared photocatalyst is a ternary composite of DyVO 4, AgBr and Ag. A photodegradation experiment and a cyclic test verified that the composite catalyst has high activity and stability, indicating that the photocatalyst has a wide application potential. The optimal AgBr/DyVO 4 sample can degrade 85% of RhB (20 ppm) under visible light irradiation for 12 min. The degradation rate reaches 0.290 min ?1, which is 14.5 times higher than that of AgBr. The high activity can be ascribed to the coupling effect between AgBr, DyVO 4 and Ag, which leads to high separation efficiency of electrons and holes. 相似文献
16.
采用电化学方法制备Ag@AgI/Ni表面等离子体薄膜催化剂,使用扫描电镜(SEM),X射线衍射(XRD)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶体结构、光谱特性以及能带结构进行分析表征,在模拟太阳光照射下,把罗丹明B作为模拟污染物对薄膜的光催化活性与稳定性进行评价,采用向反应体系中加入活性物种捕获剂的方法对薄膜光催化机理进行探究。结果表明:最佳工艺下制备的Ag@AgI/Ni薄膜表面是由附着少量Ag粒子的AgI纳米晶构成。薄膜具有显著的表面等离子共振作用、优异的光催化活性和突出的光催化稳定性。光催化反应60 min,薄膜对罗丹明B的降解率(81.1%)是AgI/Ni薄膜的1.35倍,是TiO_2(P25)/ITO薄膜的1.61倍。在薄膜光催化活性基本保持不变的前提下可循环使用5次。薄膜表面纳米Ag的等离子共振对光阴极反应的活化是光催化性能提高的重要原因。提出了薄膜光催化降解罗丹明B的反应机理。 相似文献
17.
Bi 2O 3/BiFeO 3 composite was successfully fabricated by a conventional sol–gel method and structural properties were characterized based on X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy-dispersive X-ray analyzer, nitrogen adsorption–desorption measurement, and UV–visible diffuse reflectance spectroscopy. Bi 2O 3/BiFeO 3 had a good absorption for visible light, which was benefit to photocatalytic activity. The highest degradation efficiency was obtained when the content of Bi 2O 3 in Bi 2O 3/BiFeO 3 was 63.9%. Effect of experimental conditions was investigated, and the highest photocatalytic activity of Bi 2O 3/BiFeO 3 was observed at photocatalyst dosage of 0.5 g/L, initial BPA concentration of 10 mg/L, and solution pH of 6.3. Bi 2O 3/BiFeO 3 photocatalyst exhibited enhanced photocatalytic activity for BPA, and the reaction rate constant over Bi 2O 3/BiFeO 3 composite was 2.23, 3.65, and 8.71 times higher than that of BiFeO 3, Bi 2O 3 and commercial TiO 2 (P25), respectively. Bi 2O 3/BiFeO 3 showed high photocatalytic activity after three cycles, suggesting that it was a stable photocatalyst. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The hydroxyl and superoxide radicals together with photogenerated holes played significant roles in the photocatalytic reaction. 相似文献
18.
In the present study, Nd 3+-doped ZnSe nanoparticles with variable Nd contents were successfully synthesized via a hydrothermal process using Neodymium (III) chloride hexahydrate as the doping source. X-ray diffraction, UV–Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy and transmission electron microscopy were used for characterization of the synthesized nanoparticles. It was confirmed by the DRS analysis that both of the undoped and Nd-doped ZnSe samples had significant optical absorption in the visible light range. The photocatalytic performance of as-synthesized nanoparticles was investigated towards the decolorization of C. I. Acid Orange 7 solution under visible light irradiation. Results indicated that the loading of Nd dopant into ZnSe nanoparticles significantly enhanced the photocatalytic activity of pure ZnSe with increasing Nd loading up to 6 mol% (color removal efficiency of 24.31 % for ZnSe and 84.20 % for Nd 0.06Zn 0.94Se after 120 min of treatment) and then the photocatalytic activity began to decrease. 相似文献
19.
TiO 2 nanopowders doped by Si and Zr were prepared by sol–gel method. The effects of Si and Zr doping on the structural, optical, and photo-catalytic properties of titania nanopowders have been studied by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and UV–Vis absorption spectroscopy. XRD results suggest that adding impurities has a significant effect on anatase phase stability, crystallinity, and particle size of TiO 2. Titania rutile phase formation in ternary system (Ti–Si–Zr) was inhibited by Zr 4+ and Si 4+ co-doped TiO 2 in high temperatures (500–900 °C) and 36 mol% anatase composition is retained even after calcination at 1,000 °C. The photocatalyst activity was evaluated by photocatalytic degradation kinetics of aqueous methylen orange under visible radiation. The results show that the photocatalytic activity of the 20 %Si and 15 %Zr co-doped TiO 2 nanopowders have a larger degradation efficiency than pure TiO 2 under visible light. 相似文献
20.
A novel Cs 0.33WO 3/LDHs (CWLDH) composite was synthesized by simple two steps solvothermal method and first investigated as the photocatalyst for tetracycline (TC) and Congo red (CR) degradation under visible light irradiation. The CWLDH heterostructures catalysts were characterized by XRD, UV–Vis, SEM, XPS and BET. The composite CWLDH showed enhanced photocatalytic activity compared with pure Cs 0.33WO 3 and NiAl‐LDH under identical experimental conditions. The enhanced photocatalytic activity was mainly attributed to the higher visible light‐absorbing ability, efficient electron–hole separation and prolonged lifetimes of photogenerated charges. The photocatalyst presented a high photocatalytic activity (92%) at the optimum of CWLDH ‐3 and initial TC concentration of 40 mg L −1. Besides, the degradation efficiency of TC is higher than 75% for reused CWLDH after four cycles, demonstrating that it could be used as a potential catalyst with good photocatalytic activity, stability and reusability. According to the experimental results, a possible photocatalytic mechanism of CWLDH was discussed. 相似文献
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