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1.
In this paper, novel quaternary Fe 3O 4/ZnO/AgBr/Ag 3PO 4 nanocomposites with different weight percents of Ag 3PO 4 were successfully prepared through refluxing method at 96 °C. The as-prepared products were characterized with XRD, EDX, SEM, TEM, UV-vis DRS, FT-IR, PL, and VSM techniques to determine their phase structure, purity, morphology, spectroscopic, and magnetic properties. Photocatalytic degradation of rhodamine B under visible-light irradiation indicated that the nanocomposite with 20% of Ag 3PO 4 has the best activity. Photocatalytic activity of this nanocomposite is nearly 68, 5.0, and 3.4-folds greater than those of the Fe 3O 4/ZnO, Fe 3O 4/ZnO/AgBr, and Fe 3O 4/ZnO/Ag 3PO 4 samples in degradation of rhodamine B, whereas 17, 6.7, and 2.8-folds greater in degradation of methylene blue, respectively. The activity enhancement was mainly ascribed to the enhanced visible-light absorption ability and formation of tandem n-n heterojunctions between counterparts of the nanocomposites, which facilitate the generation and separation of charge carriers. An additional advantage of these photocatalysts is magnetic recoverability using external magnetic field. In addition, using different scavengers, superoxide ion radicals were identified as the main oxidative species in the degradation reaction of rhodamine B. Finally, photocatalytic stability of the nanocomposite was evaluated for six cycles. 相似文献
2.
A series of novel magnetically separable Fe 3O 4/ZnO/CoWO 4 nanocomposites with different contents of CoWO 4 were fabricated using a facile refluxing method at 96 °C followed by a calcination step. The structure, purity, morphology, spectroscopic, and magnetic properties of the prepared samples were characterized by XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, PL, and VSM techniques. Photocatalytic activity of the nanocomposites was investigated by degradation of rhodamine B, methylene blue, methyl orange, and fuchsine under visible-light irradiation. The results showed remarkably enhanced activity for the Fe 3O 4/ZnO/CoWO 4 (30%) nanocomposite relative to the Fe 3O 4/ZnO and Fe 3O 4/CoWO 4 samples. The degradation rate constant of RhB over the optimal nanocomposite is nearly 24 and 5 times higher than those of the Fe 3O 4/ZnO and Fe 3O 4/CoWO 4 samples, respectively. The intensive absorption of visible light and separation efficiency of the photogenerated electron–hole pairs in the ternary nanocomposites were confirmed by UV–vis DRS and PL techniques, respectively. In addition, a plausible mechanism for separation of the electron–hole pairs based on p–n heterojunction was proposed. 相似文献
3.
Ag 2WO 4/g-C 3N 4 composites with different Ag 2WO 4 concentration and calcination temperature were synthesized via a mixing and heating approach. Various techniques were used to investigate the characters of the as-prepared samples, such as thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. The degradation of rhodamine B (20 ppm) under visible light was performed to investigate the photocatalytic activity of Ag 2WO 4/g-C 3N 4 composites. Results indicate that the Ag 2WO 4/g-C 3N 4 is actually Ag/Ag 2WO 4/g-C 3N 4 ternary system. 7.5 wt% Ag 2WO 4/g-C 3N 4 prepared at 300 °C presented the best photocatalytic performance in rhodamine B degradation. The degradation rate reaches 0.0679 min ?1, which is 3.25 times higher than the value of pure g-C 3N 4. The enhanced activity is attributed to the synergetic effect of Ag 2WO 4, g-C 3N 4 and metal Ag. Additionally, cycling experiments also proved that the Ag 2WO 4/g-C 3N 4 photocatalyst has good stability. 相似文献
4.
Novel CdS/BiVO 4 nanocomposites were synthesized by simple solvothermal method. The as-prepared samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis diffuse reflectance spectra (DRS), Fourier transform infrared spectra (FT-IR) and photoluminescence (PL). In the nanocomposites, CdS particles were deposited on the surface of the BiVO 4. The photocatalytic tests showed that the CdS/BiVO 4 nanocomposites possessed a higher rate for degradation of malachite green (MG) than the pure BiVO 4 under visible light irradiation. The 1.5-CdS/BiVO 4 nanocomposite photocatalyst was found to degrade 98.3% of MG under visible light irradiation. Moreover, the photocatalytic mechanism of CdS/BiVO 4 nanocomposites was also discussed. The results showed that the nanocomposite construction between CdS and BiVO 4 played a very important role in their photocatalytic properties, which has the potential application in solving environmental pollution issues utilizing solar energy effectively. 相似文献
5.
A visible light active photocatalyst, Ag/TiO 2/MWCNT was synthesized by loading of Ag nanoparticles onto TiO 2/MWCNT nanocomposite. The photocatalytic activity of Ag/TiO 2/MWCNT ternary nanocomposite was evaluated for the degradation of methylene blue dye under UV and visible light irradiation. Ag/TiO 2/MWCNT ternary nanocomposite exhibits (~9 times) higher photocatalytic activity than TiO 2/MWCNT and (~2 times) higher than Ag/TiO 2 binary nanocomposites under visible light irradiation. The enhancement in the photocatalytic activity is attributed to the synergistic effect between Ag nanoparticles and MWCNT, which enhance the charge separation efficiency by Schottky barrier formation at Ag/TiO 2 interface and role of MWCNT as an electron reservoir. Effect of different scavengers on the degradation of methylene blue dye in the presence of catalyst has been investigated to find the role of photogenerated electrons and holes. Simultaneously, the Ag/TiO 2/MWCNT shows excellent photocatalytic stability. This work highlights the importance of Ag/TiO 2/MWCNT ternary nanocomposite as highly efficient and stable visible-light-driven photocatalyst for the degradation of organic dyes. 相似文献
6.
Novel plasmonic photocatalyst of Ag/AgCl-CdWO 4 was successfully synthesized via an in situ loading and photoreduction process. The as-obtained Ag/AgCl-CdWO 4 samples were characterized by various analytical techniques. The Ag/AgCl-CdWO 4 nanocomposites present a remarkable visible-light photocatalytic activity. The optimal Ag/AgCl-CdWO 4 can completely degrade RhB, MB and MO within 30 min. Moreover, 95% of phenol can also be degraded within 90 min. The enhanced photocatalytic activity was mainly attributed to two factors: the strong SPR of Ag NPs would improve the visible-light absorbance effectively. Simultaneously, the photo-generated electron–hole pairs can transfer and separate among the Ag/AgCl-CdWO 4 hybrid effectively. 相似文献
7.
A hydrothermal method was used to prepare YVO 4 nanoparticles, and a photo-assisted deposition method was used to load Ag onto the YVO 4. The photocatalytic performances of the prepared photocatalysts were tested by the degradation of methylene-blue dye using visible-light irradiation. The results indicate that the Ag is well-dispersed within the YVO 4, and the surface area of the Ag/YVO 4 is smaller than that of the YVO 4 samples. The sample with 0.3 wt% Ag/YVO 4 has the highest activity for the removal of methylene-blue dye. The 0.3 wt% Ag/YVO 4 can be used five times without the loss of its photocatalytic activity. 相似文献
8.
The present work is focused on the preparation of hybrid ZnO/TiO 2/Ag 2O nanocomposite for enhanced photocatalytic activity. The resultant samples are characterized by using XRD, SEM, EDX, HR-TEM, UV-DRS, BET and XPS techniques. X-ray diffraction analysis indicates the co-existence of wurtzite, anatase and cubic phases in ZnO/TiO 2/Ag 2O nanocomposite. The band gap energy value of the photocatalyst is 3.39 eV, which has been evidenced from UV–visible diffuse reflectance spectroscopy measurements. Photocatalytic degradation of methylene blue dye has been investigated by using UV–visible spectrophotometer. From the result, it has been concluded that ZnO/TiO 2/Ag 2O nanocomposite has proven to be an efficient photocatalyst under UV irradiation when compared to that of mono and binary oxide systems. Further, the possible photodegradation mechanism is proposed to support the enhancement of photocatalytic activity towards degradation of dyes. 相似文献
9.
Heterogeneous Ag/Ag 3PO 4/BiPO 4 photocatalyst was synthesized by a one-step low temperature chemical bath method and exhibited better photocatalytic activity and better stability than those of individual Ag 3PO 4 or BiPO 4 nanoparticles for photodegradation of organic compounds (Rhodamine B) in the absence of electron accepters under visible light ( λ>420 nm). The enhanced photocatalytic performance is mainly ascribed to the strong visible-light absorption originating from high efficient separations of photogenerated electron–hole pairs through Ag 3PO 4/BiPO 4 and Ag/Ag 3PO 4 heterostructures. 相似文献
10.
In this research, novel ternary Ag/αFe 2O 3-rGO nanocomposites with various contents of GO were synthesized via a facile one-pot hydrothermal method. Ag/αFe 2O 3-rGO nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR). The results showed that hematite nanoparticles and Ag nanoparticles were well decorated on the graphene surface. Photocatalytic activity of Ag/αFe 2O 3-rGO ternary nanocomposites and pure Ag/αFe 2O 3 was investigated for photodegradation of Congo red dye solution as a model pollutant under UV light irradiation. The ternary nanocomposite with 1.8?mg/ml GO aqueous solution concentration shows higher degradation efficiency under UV light irradiation than the pure Ag/αFe 2O 3 and the nanocomposites with other GO aqueous solution concentrations. It was observed that the adsorption of the dyes on the nanocomposites surface is dependent on the graphene content due to a decrease in the recombination rate, particles size, and increase charge carrier transfer. The results show that the Ag/αFe 2O 3-rGO nanocomposite can be used as an excellent photocatalytic material for degradation of Congo red dye in wastewater. A possible photocatalytic mechanism was proposed for degradation of Congo red dye. 相似文献
11.
In this study, we report novel magnetically separable g-C 3N 4/AgBr/Fe 3O 4 nanocomposites as visible-light-driven photocatalysts. The preparation method was simple, large-scale, and low-temperature and did not require any additives or post preparation treatments. The nanocomposites were characterized using X-ray diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV–vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and vibrating sample magnetometry techniques. Photocatalytic activity of the nanocomposites was investigated by degradation of rhodamine B under visible-light irradiation. The nanocomposite with 4:1 weight ratio of g-C 3N 4/AgBr to Fe 3O 4 exhibited superior activity in the degradation reaction. Activity of this nanocomposite was about 5.3 and 5-fold higher than those of g-C 3N 4, and g-C 3N 4/Fe 3O 4, respectively. Moreover, we investigated the influence of refluxing time, calcination temperature, and scavengers of reactive species on the degradation activity. Finally, the photocatalyst was magnetically separated, with high efficiency, from the treated solution after five successive cycles. 相似文献
12.
The Ag 3PO 4/Bi 2WO 6 hierarchical heterostructures were prepared by a combination of hydrothermal technique and in situ precipitation method for the first time. The Ag 3PO 4/Bi 2WO 6 hierarchical heterostructures displayed enhanced visible-light photocatalytic activity against phenol. The enhanced photocatalytic activity could be attributed to the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the Ag 3PO 4/Bi 2WO 6 heterojunction interface. Repetitive tests showed that the Ag 3PO 4/Bi 2WO 6 hierarchical heterostructures maintained high catalytic activity over several cycles, and it had a better regeneration capability under mild conditions. 相似文献
13.
Ag/g-C 3N 4 photocatalysts were synthesized by a rapid microwave-assisted polyol process. The characterization results showed monodisperse Ag nanoparticles with diameters of a few nanometers closely attached to the edges of g-C 3N 4. The presence of Ag nanoparticles in Ag/g-C 3N 4 photocatalysts enhanced the visible-light absorption and suppressed the recombination of photogenerated electron/hole pairs. The Ag/g-C 3N 4 photocatalysts exhibited the superior visible-light responsive photocatalytic activity for rhodamine B degradation. The mechanism of visible-light induced photocatalysis over Ag/g-C 3N 4 photocatalysts was also discussed. 相似文献
14.
A series of direct Z-scheme FeIn 2S 4/Bi 2WO 6 hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn 2S 4/Bi 2WO 6 nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn 2S 4 and Bi 2WO 6. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn 2S 4 in FeIn 2S 4/Bi 2WO 6 nanocomposites and the optimized component ratio of FeIn 2S 4 to Bi 2WO 6 is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn 2S 4/Bi 2WO 6 nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment. 相似文献
15.
AgI/TiO 2 and Ag/TiO 2 porous nanostructures were synthesized using AgNO 3, KI, thioglycollic acid, and tetrabutyl orthotitanate as a precursor. AgI nanoparticles were used as seeds to initiate the nucleation of a precursor TiO 2 shell, and thioglycollic acid acted as a hydrolysis inhibitor and porosity promoter. The hybridized samples were annealed at different temperatures. Porous AgI/TiO 2 nanostructures were formed at low annealing temperatures (300 and 400 °C). At 600 °C, the porous Ag/TiO 2 nanostructures exhibited a plasmon resonance effect. The formation mechanism of the different porous nanostructures was also investigated. Methylene blue solutions were used as wastewater to evaluate the visible-light photocatalytic activity of the samples. The porous nanostructured photocatalyst exhibited substantially high visible-light-induced photocatalytic activity for the photodegradation of methylene blue compared with pristine AgI and TiO 2 nanoparticles. 相似文献
16.
Polyurethane acrylate (PUA)–Ag/TiO 2 nanocomposites were synthesized through in situ polymerization. The well-dispersed Ag/TiO 2 nanorods serve as photoinitiator. Meanwhile, the PUA–Ag/TiO 2 nanocomposite films exhibit superior activity toward the photocatalytic degradation of Escherichia coli under UV light. The excellent UV curing and antibacterial activities can be ascribed to the synergistic effect of Ag and TiO 2, which promotes the effective electron/hole separation and thus generates various reactive species. Thin films with these nanoparticles are more hydrophilic after UV illumination. And the antibacterial mechanism of the UV-curable PUA–Ag/TiO 2 nanocomposites was proposed. 相似文献
17.
Introducing magnetic metal onto semiconductor materials has been proven to be an attractive strategy for enhancing the photocatalytic activity in the visible region. In this work, ternary heterostructure magnetic semiconductor photocatalyst RGO/ZnFe2O4/Ag2WO4 was successfully synthesized through a simple hydrothermal method and was evaluated by photodegradation of Rhodamine B (RhB) under visible light irradiation. The composition, structure, morphology, and optical absorption properties of the as-prepared photocatalyst were investigated by XRD, FT-IR, SEM, and UV–Vis DRS, respectively. It was found that the photocatalytic activity under visible light irradiation was in the order of RGO/ZnFe2O4/Ag2WO4?>?ZnFe2O4?>?Ag2WO4?>?RGO/ZnFe2O4 and RGO/ZnFe2O4/Ag2WO4. The enhancement of photocatalytic performance could be attributed to the reduced graphene oxide sheets can function as an electron collector and transporter to lengthen the lifetime of the charge carriers, improving the whole photocatalytic activity. The reaction kinetics, possible degradation pathway, and catalyst stability, as well as the roles of ZnFe2O4 and Ag2WO4 in photoreaction, were comprehensively studied. The obtained results indicate that the prepared magnetic and effective catalytic materials could be potentially applied in environmental organic pollutants purification. 相似文献
18.
The heterogeneous titanium oxide-reduced graphene oxide-silver (TiO 2/RGO/Ag) nanocomposites were successfully prepared by incorporation of two dimensional (2D) RGO nanosheets and spherical silver nanoparticles (NPs) into the 1D TiO 2 nanofibers. The novel TiO 2/RGO/Ag nanocomposites were synthesized by loading TiO 2 nanofibers, prepared via electrospinning technique, on the RGO/Ag platform. The resulting nanocomposites have been characterized using various techniques containing transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and ultra-violet-visible (UV–vis) spectroscopy. Microscopic studies clearly verified the existence of TiO 2 nanofibers with Ag NPs on the surface of RGO sheet and formation of TiO 2/RGO/Ag nanocomposites. Moreover, the results of UV–vis spectroscopy demonstrated that TiO 2/RGO/Ag nanocomposites extended the light absorption spectrum toward the visible region and significantly enhanced the visible-light photocatalytic performance of the prepared samples on degradation of rhodamine B (Rh. B) as a model dye. It was found that, incorporation of 50 µl RGO/Ag into the TiO 2 nanofibers lead to a maximum photocatalytic performance. Also, the improvement of the inactivation of Escherichia coli ( E. coli) bacteria under visible-light irradiation was revealed by introduction of RGO/Ag into the TiO 2 matrix. The significant enhancement in the photo and bio-activity of TiO 2/RGO/Ag nanocomposites under visible-light irradiation can be ascribed to the RGO/Ag content by acting as electron traps in TiO 2 band gap. 相似文献
19.
Zinc Oxide (ZnO), ZnO/GO (Graphene Oxide) and ZnO:Ag/GO nanocomposite thin films were deposited on glass substrates using a simple cost-effective automated jet nebulizer spray pyrolysis technique for photocatalytic degradation of organic dyes. The ZnO:Ag/GO film exhibits superior photocatalytic activity when compared with ZnO and ZnO/GO films. The degradation rate constant values of pristine ZnO and ZnO/GO films are found to be 0.0143 and 0.0176 min −1, respectively whereas that of ZnO:Ag/GO is 0.0567 min −1. The possible mechanism involved in the enhanced photocatalytic activity of ZnO:Ag/GO films for the degradation of Methylene Blue dye is proposed with the help of structural, optical and photoluminescence studies. The powder XRD profile confirms the hexagonal wurtzite structure of the synthesized catalysts. The results of Raman, XPS and EDX studies confirm the presence of GO in the ZnO/GO and GO and Ag in the ZnO:Ag/GO films. 相似文献
20.
Preparation of visible-light active photocatalysts for efficient degradation of pollutants from the industrial wastewater has received considerable attention in recent decades. The present study introduces a new sonochemical route for the preparation of graphene/TiO 2/Ag nanocomposite for visible-light photocatalytic degradation of X6G (C.I. Reactive Yellow 2), a commonly used textile azo-dye. The obtained graphene/TiO 2/Ag nanocomposite is extracted from the reaction solution by two drying methods: (1) conventional centrifuging and drying, and (2) freeze drying. Both of the dried samples are calcinated at 500 °C. The TEM images reveal that distribution of TiO 2/Ag nanoparticles within the graphene sheets in the freeze dried nanocomposite is better than the conventional dried sample. Furthermore, the freeze dried nanocomposite has higher photocatalytic activity than the other nanocomposite. In conventional centrifuging and drying method, some of the TiO 2/Ag nanoparticles are gradually pushed out from the graphene sheets during the drying process and graphene layers are stacked, therefore the dispersion effect of sonication is destroyed. However, in the freeze dried nanocomposite, because of the fast freezing of the sonicated sample by liquid N 2, the TiO 2/Ag nanoparticles are kept between the graphene sheets and calcination process attached and fixed them to the graphene, preserving the dispersion effect of sonication. 相似文献
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