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1.
Samarium and nitrogen co‐doped Bi 2WO 6 nanosheets were successfully synthesized by using a hydrothermal method. The crystal structures, morphology, elemental compositions, and optical properties of the prepared samples were investigated. The incorporation of samarium and nitrogen ions into Bi 2WO 6 was proved by X‐ray diffraction, energy dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy. UV/Vis diffuse reflectance spectroscopy indicated that the samarium and nitrogen co‐doped Bi 2WO 6 possessed strong visible‐light absorption. Remarkably, the samarium and nitrogen co‐doped Bi 2WO 6 exhibited higher photocatalytic activity than single‐doped and pure Bi 2WO 6 under visible‐light irradiation. Radical trapping experiments indicated that holes (h +) and superoxide radicals ( . O 2?) were the main active species. The results of photoluminescence spectroscopy and photocurrent measurements demonstrated that the recombination rate of the photogenerated electrons and holes pairs was greatly depressed. The enhanced activity was attributed to the synergistic effect of the in‐built Sm 3+/Sm 2+ redox pair centers and the N‐doped level. The mechanism of the excellent photocatalytic activity of Sm‐N‐Bi 2WO 6 is also discussed. 相似文献
2.
Novel Bi 2WO 6‐coupled Fe 3O 4 magnetic photocatalysts with excellent and stable photocatalytic activity for degrading tetracycline hydrochloride and RhB were successfully synthesized via a facile solvothermal route. Through the characterization of the as‐prepared magnetic photocatalysts by X‐ray diffractometry, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectra, it was found that the as‐prepared magnetic photocatalysts were synthesized by the coupling of Bi 2WO 6 and Fe 3O 4, and introduction of appropriated Fe 3O 4 can improve nanospheres morphology and visible‐light response. Among them, BFe2 (0.16% Fe 3O 4) exhibited the best photocatalytic activity for degradation of tetracycline hydrochloride (TCH), reaching 81.53% after 90 min. Meanwhile, the as‐prepared magnetic photocatalysts showed great separation and recycle property. Moreover, the results of electrochemical impedance spectroscopy demonstrated that the well conductivity of Fe 3O 4 can promote photogenerated charge carriers transfer and inhibit recombination of electron–hole pairs, so that Bi 2WO 6/Fe 3O 4 exhibited enhanced photocatalytic activity on degradation of TCH and RhB. Hence, this work provides a principle method to synthesize Bi 2WO 6/Fe 3O 4 with excellent photocatalytic performance for actual application, in addition, it showed that introduction of Fe 3O 4 not only can provide magnetism, but also can enhance photocatalytic activity of Bi 2WO 6/Fe 3O 4 magnetic photocatalysts. 相似文献
3.
The reduced graphene oxide‐Bi 2WO 6 (rGO‐BWO) photocatalysts with the different R F/O values (molar ratio of the F molar mass and the O's molar mass of Bi 2WO 6) had been successfully synthesized via one‐step hydrothermal method. The F‐doped rGO‐BWO samples were characterized by X‐ray diffraction patterns (XRD), field‐emission scanning electron microscopy (FE‐ESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area (BET), X‐ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results indicate that F ? ions had been successfully doped into rGO‐BWO samples. With the increasing of the R F/O values from 0 to 2%, the evident change of the morphology and the absorption edges of F‐doped rGO‐BWO samples and the photocatalytic activities had been enhanced. Moreover, the photocatalytic activity of F‐doped rGO‐BWO with R F/O = 0.05 were better than rGO‐BWO and the other F‐doped rGO‐BWO under 500 W Xe lamp light irradiation. The enhanced photocatalytic activity can be attributed to the morphology of the intact microsphere that signify the bigger specific surface area for providing more possible reaction sites for the adsorption–desorption equilibrium of photocatalytic reaction, the introduction of F ? ions that may cause the enhancement of surface acidity and creation of oxygen vacancies under visible light irradiation, the narrower band gap which means needing less energy for the electron hole pair transition. 相似文献
4.
A novel visible light-responsive homogeneous catalyst based on Bi 2WO 6 quantum dots (QDs-BWO)/Bi 2WO 6 nanosheets (N-BWO) was successfully fabricated through a simple hydrothermal method. A variety of techniques were employed to investigate the morphology, structure, and electronic properties of the samples. The photocatalytic performance of the QDs/N-BWO materials was investigated by monitoring the degradation of 4-chlorophenol and rhodamine B under visible light irradiation. The as-fabricated QDs/N-BWO materials showed higher photocatalytic activity than both QDs-BWO and N-BWO. The results reveal that the incorporation of the QDs improved the separation efficiency of electron-hole pairs, leading to enhanced photocatalytic activity. Moreover, the results of quenching experiments show that ·O 2– species played a major role in the degradation process. This work provides an important reference for the fabrication of homogeneous catalysts with high performance in the degradation of different types of pollutants. 相似文献
5.
Bi 2WO 6 microstructures were synthesized through hydrothermal process and Ag@Bi 2WO 6 composites were synthesized by simple UV light irradiation for 5 min using Bi 2WO 6 and AgNO 3 as raw materials. Ag@Bi 2WO 6 composites were characterized by X‐ray powder diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), and UV‐Vis absorption spectrum (UV‐Vis). Few Ag deposited on the Bi 2WO 6 leads to an increase in photocatalytic activity, which clearly indicates that the recombination of photogenerated charge carrier between the hybrid orbital of Bi6s and O2p (valence band) to the empty W5d orbital is inhibited greatly in the Ag@Bi 2WO 6 composite. In addition, a few H 2O 2 will greatly enhance photocatalytic activity of Ag@Bi 2WO 6, and the proper reason is discussed. 相似文献
6.
Hierarchical Ag/Bi 2WO 6 nanomaterials were prepared by a facile one-step hydrothermal method in mixed acetic acid and ethylene glycol (EG) medium. EG is employed as mild reducing agent for the formation of metallic Ag from Ag + precursors. In situ energy dispersive X-ray diffraction (EDXRD) monitoring showed that the hydrothermal formation kinetics of Bi 2WO 6 in the presence of EG was significantly slowed down due to its very high viscosity. The photocatalytic activities of Ag/Bi 2WO 6 composites were evaluated by the photodegradation of methylene blue (MB) under visible light irradiation. The photocatalytic activity of Bi 2WO 6 is strongly influenced by the Ag loading. The enhanced catalytic activity of the composites is based on the cooperative effects of plasmon absorption band and separation of photogenerated electron-hole pairs. 相似文献
7.
CeO 2/Bi 2WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2/Bi 2WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible‐light irradiation. The 1CeO 2/2Bi 2WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2WO 6 in the as‐prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2/Bi 2WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2/Bi 2WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. 相似文献
8.
In this work, we report a novel AgBi(WO 4) 2–Bi 2WO 6 heterostructure, which was designed and synthesized by using a simple hydrothermal method. Methyl orange was used as a representative dye indicator to evaluate the visible‐light catalytic activity and the catalytic mechanism was investigated. The as‐synthesized AgBi(WO 4) 2–Bi 2WO 6 composite displayed a 43 times higher photocatalytic activity than Bi 2WO 6. Owing to the matched band gap and distinctive heterostructure, AgBi(WO 4) 2–Bi 2WO 6 reveals a high visible‐light response and high‐efficiency utilization of both photogenerated electrons and holes. AgBi(WO 4) 2 reveals a similar energy level to and good lattice match with Bi 2WO 6, which are favorable qualities for band bending and fluent electron transfer. Furthermore, the photoexcited electrons can produce oxygen to generate .O 2? radicals, which is vital for the overall utilization of both holes and electrons. This is the first example of AgBi(WO 4) 2 being used as photocatalytic material. 相似文献
9.
Bi 2WO 6/TiO 2 heterojunction photocatalysts with two different microstructures were controllably fabricated via a facile two-step synthetic route. XRD, XPS, SEM, TEM, BET-surface, DRS, PL spectra, photoelectrochemical measurement (Mott-Schottky), and zeta-potential analyzer were employed to clarify structural and morphological characteristics of the obtained products. The results showed that Bi 2WO 6 nanoparticles/nanosheets grew on the primary TiO 2 nanorods. The TiO 2 nanorods used as a synthetic template inhibit the growth of Bi 2WO 6 crystals along the c-axis, resulting in Bi 2WO 6/TiO 2 heterostructure with one-dimensional (1D) morphology. The photocatalytic properties of Bi 2WO 6/TiO 2 heterojunction photocatalysts were strongly dependent on their shapes and structures. Compared with bare Bi 2WO 6 and TiO 2, Bi 2WO 6/TiO 2 composite have stronger adsorption ability and better visible light photocatalytic activities towards organic dyes. The Bi 2WO 6/TiO 2 composite prepared in EG solvent with optimal Bi:Ti ratio of 2:12 (S-TB2) showed the highest photocatalytic activity, which could totally decompose Rhodamine B within 10 min upon irradiation with visible light (λ > 422 nm), and retained the high photocatalytic performance after five recycles, confirming its stability and practical usability. The results of PL indicated that Bi 2WO 6 and TiO 2 could combine well to form a heterojunction structure which facilitated electron–hole separation, and lead to the increasing photocatalytic activity. 相似文献
10.
Uniform Bi 2WO 6 spheres with high visible light activity were prepared via a solvothermal route. A variety of techniques including transmission electron micrographs (TEM), X-ray powder diffraction (XRD), N 2 adsorption, FT-IR spectra, and UV–Vis spectra were employed to characterize the structure of the Bi 2WO 6 materials so obtained. The results show that the sphere-like Bi 2WO 6 samples were successfully prepared. And, under the photocatalytic degradation of Rhodamine B, the samples demonstrated high activity, three times higher than that of a sample from the solid-state method. Moreover, the uniform structure made the sample easy to separate from the reaction solution, providing an intrinsic advantage to the normal Bi 2WO 6 samples. 相似文献
11.
以工业固体废弃物粉煤灰漂珠(fly ash cenospheres,FACs)为载体,采用水热法制备了新颖的漂珠负载Bi2WO6复合材料(Bi2WO6/FACs),通过X射线衍射(XRD),扫描电子显微镜(SEM),X-射线光电子能谱(XPS),和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi2WO6的特征衍射峰。DRS结果证实了引入FACs后Bi2WO6对可见光的吸收增强。在可见光的照射下,以亚甲基蓝溶液的光催化降解评价了Bi2WO6/FACs复合材料的光催化性能。结果表明:Bi2WO6/FACs的光催化性能优于纯Bi2WO6的,其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性,Bi2WO6/FACS复合光催化剂可长时间漂浮于水面,既能充分吸收光能,又有利于催化剂的回收和重复利用。 相似文献
12.
以工业固体废弃物粉煤灰漂珠(fly ash cenospheres, FACs)为载体, 采用水热法制备了新颖的漂珠负载Bi 2WO 6复合材料(Bi 2WO 6/FACs), 通过X射线衍射(XRD), 扫描电子显微镜(SEM), X-射线光电子能谱(XPS), 和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi 2WO 6的特征衍射峰。DRS结果证实了引入FACs后Bi 2WO 6对可见光的吸收增强。在可见光的照射下, 以亚甲基蓝溶液的光催化降解评价了Bi 2WO 6/FACs复合材料的光催化性能。结果表明:Bi 2WO 6/FACs的光催化性能优于纯Bi 2WO 6的, 其一级反应速率常数( k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性, Bi 2WO 6/FACS复合光催化剂可长时间漂浮于水面, 既能充分吸收光能, 又有利于催化剂的回收和重复利用。 相似文献
13.
In this paper, Bi 2O 3 and rare earth (La, Ce)‐doped Bi 2O 3 visible‐light‐driven photocatalysts were prepared in a Triton X‐100/ n‐hexanol/cyclohexane/water reverse microemulsion. The resulting materials were characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, photoluminescence spectra (PLS) and UV–Vis diffuse reflectance spectroscopy. The XRD patterns of the as‐prepared catalysts calcined at 500°C exhibited only the characteristic peaks of monoclinic α‐Bi 2O 3. PLS analysis implied that the separation efficiency for electron‐hole has been enhanced when Bi 2O 3 was doped with rare earth. UV–Vis diffuse reflectance spectroscopy measurements presented an extension of light absorption into the visible region. The photocatalytic activity of the samples was evaluated by degradation of methyl orange (MO) and 2,4‐dichlorophenol (2,4‐DCP). The results displayed that the photocatalytic activity of rare earth‐doped Bi 2O 3 was higher than that of dopant‐free Bi 2O 3. The optimal dopant amount of La or Ce was 1.0 mol%. And the mechanisms of influence on the photocatalytic activity of the catalysts were discussed. 相似文献
14.
Plasmonic Ag/AgCl‐modified bismuth subcarbonate (Bi 2O 2CO 3) composites were prepared by a multistep process with hydrothermal, deposition, and photoreduction in the absence of organic capping agents. The properties of the obtained Ag/AgCl/Bi 2O 2CO 3 samples were characterized using X‐ray diffraction, field emission scanning electron microscopy and X‐ray photoelectron, UV–visible diffuse reflectance, and photoluminescence spectroscopies. The results reveal that Ag/AgCl nanoparticles are dispersed on the Bi 2O 2CO 3 surface to achieve plasmonic Ag/AgCl/Bi 2O 2CO 3. The Ag/AgCl/Bi 2O 2CO 3 nanocomposites show improved rhodamine B (RhB) adsorption capacity and photocatalytic activity compared with pure Bi 2O 2CO 3 and Ag/AgCl. In addition, the Ag/AgCl/Bi 2O 2CO 3 composite with 20 wt% Ag/AgCl exhibits the highest photocatalytic activity and remains stable for the photodegradation of RhB under visible light. The enhanced photocatalytic activity of Ag/AgCl/Bi 2O 2CO 3 may be attributed to the surface plasmon resonance effect of in situ generated Ag nanoparticles and synergistic effect of Ag/AgCl and Bi 2O 2CO 3, which increase the separation efficiency of photogenerated electron–hole pairs under visible light irradiation. 相似文献
15.
Bi 2WO 6 powder photocatalyst was prepared using Bi(NO 3) 3 and Na 2WO 4 as raw materials by a simple hydrothermal method at 150 °C for 24 h, and then calcined at 300, 400, 500, 600 and 700 °C for 2 h, respectively. The as-prepared samples were characterized with UV-visible diffuse reflectance spectra, fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and N 2 adsorption-desorption measurement. The photocatalytic activity of the samples was evaluated using the photocatalytic oxidation of formaldehyde at room temperature under visible light irradiation. It was found that post-treatment temperature obviously influenced the visible-light photocatalytic activity and physical properties of Bi 2WO 6 powders. At 500 °C, Bi 2WO 6 powder photocatalyst showed the highest visible-light photocatalytic activity due to the samples with good crystallization and high BET surface area. 相似文献
16.
Near‐monodisperse Bi‐doped anatase TiO 2 nanospheres with almost uniform diameters in the range of 117 to 87 nm were prepared simply by introducing different amounts of bismuth nitrate pentahydrate into the reaction system and subsequent calcinations. X‐ray diffraction, UV‐visible diffuse reflectance spectra, and X‐ray photoelectron spectroscopy confirm that the doped ions substitute some of the lattice titanium atoms, and furthermore, Bi 3+ and Bi 4+ ions coexist. All the Bi‐doped TiO 2 samples show much better photocatalytic activity than pure TiO 2 in the degradation of rhodamine B (RhB) under the irradiation of visible light ( λ>420 nm), and, interestingly, it was found that the degradation mechanism is different from the conventional one, which has already been reported elsewhere. The detailed mechanism is discussed in this article. 相似文献
17.
The photocatalytic ability of ZnO is improved through the addition of flower-like Bi 2WO 6 to prepare a Bi 2WO 6/ZnO composite with visible light activity. The composite is characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and N 2 adsorption-desorption isotherms. After modification, the band gap energy of Bi 2WO 6/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV. Under visible light irradiation, the Bi 2WO 6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue (MB) and tetracycline. The photo-degradation efficiencies of (0.3:1) Bi 2WO 6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO, respectively, and correspondingly, the photo-degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO, respectively. Moreover, the photocatalyst of (0.3:1) Bi 2WO 6/ZnO exhibits a higher transient photocurrent density of approximately 4.5 μA compared with those of bare Bi 2WO 6 and ZnO nanoparticles. The successful recombination of Bi 2WO 6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO, which can be attributed to the effective separation of electron–hole pairs. Active species trapping experiments display that [O 2] ? is the major species involved during photocatalysis rather than ?OH and h +. This study provides insight into designing a meaningful visible-light-driven photocatalyst for environmental remediation. 相似文献
18.
Visible-light-driven heterostructure Ag/Bi2WO6 nanocomposites were prepared by transforming Ag+ ions into metallic Ag0 nanoparticles loaded on top of Bi2WO6 nanoplates under visible light irradiation for 1 h. XRD, XPS, SEM and TEM analyses indicated that spherical metallic Ag nanoparticles were uniformly dispersed on top of orthorhombic Bi2WO6 thin nanoplates. Rhodamine B (RhB) was used as a dye model for investigation of photocatalytic performance of Bi2WO6 nanoplates with different weight contents of Ag nanoparticles illuminated by visible radiation. In this research, 10% Ag/Bi2WO6 nanocomposites have the highest photocatalytic activity in the degradation of RhB at 94.21% within 210 min because of the rapid diffusion of electronic charge through the Schottky barrier between metallic Ag nanoparticles and Bi2WO6 thin nanoplates, good electrical conductivity of metallic Ag nanoparticles, inhibited recombination of charge carriers and enhanced photocatalytic activity of Ag/Bi2WO6 nanocomposites. Main active species of the photocatalysis and stability of the photocatalyst were also evaluated. 相似文献
19.
In this work, an Ag-loaded octahedral Bi 2WO 6 photocatalyst has been successfully prepared by the hydrothermal method and photo deposition method. X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDX), field-emission scanning electron microscopy (FE-SEM) and ultra-violet adsorption spectrum (UV-Vis) were employed for characterization of the composite photocatalyst. Furthermore, two different photocatalysts including the obtained Ag-loaded octahedral Bi 2WO 6 were employed here for photodegradation of model contaminated water of Orange II (OII). Results show that Ag-loaded Bi 2WO 6 photocatalyst exhibits superior photocatalytic properties compared to the undoped Bi 2WO 6. The reasons for improvement in photocatalytic activity of the Ag-loaded octahedral Bi 2WO 6 were also discussed. 相似文献
20.
One‐dimensional (1D) CeO 2/Bi 2WO 6 heterostructured nanofibers with a diameter of about 300 nm were successfully synthesized by using a straightforward strategy combining an electrospinning technique with a sintering process. The acquired products were characterized by thermogravimetric and differential scanning calorimetric (TG‐DSC), Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area measurements, and UV/Vis spectroscopy. The obtained CeO 2/Bi 2WO 6 heterostructured nanofibers exhibited an excellent photocatalytic property for the degradation of Rhodamine B (RhB) dye driven by visible light due to the promoted separation of photoelectrons and holes and the large contact area between the photocatalyst and organic pollutant. 相似文献
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