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1.
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
2.
Pure TiO 2 and carbon quantum dots (CQDs)-doped TiO 2 nanocomposite (CQDs/TiO 2 nanocomposite) were prepared by a sol-gel approach for photocatalytic removal of Rhodamine B and cefradine. Analyses by Transmission electronmicroscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), UV–visible spectroscopy and X-ray powder diffraction (XRD) confirmed the successful formation of CQDs/TiO 2 heterostructure. The as-prepared TiO 2 and CQDs/TiO 2 composite possessed small particles, spherical-like shape, and anatase crystal form. Meanwhile, Rhodamine B and cefradine were chosen to evaluate the photocatalytic activity of TiO 2 and CQDs/TiO 2 composite. Results revealed that with the facile decoration of CQDs, the absorption of photocatalyst was extended into visible light region and photocatalytic activity was improved in comparison with pure TiO 2. Furthermore, the mechanism for the improvement of the photocatalytic performance of the composites was discussed on the basis of the results. CQDs play an important role in the photocatalytic process, due to their superior ability to extend the visible absorption and produce more electrons and electron–hole pairs for the degradation of pollutants. In all, the paper offers further insights into the development of CQDs/TiO 2 nanocomposite as photocatalyst for the degradation of antibiotics. 相似文献
3.
A unique Cu 2O/TiO 2 nanocomposite with high photocatalytic activity was synthesized via a two-step chemical solution method and used for the photocatalytic degradation of organic dye. The structure, morphology, composition, optical and photocatalytic properties of the as-prepared samples were investigated in detail. The results suggested that the Cu 2O/TiO 2 nanocomposite is composed of hierarchical TiO 2 hollow microstructure coated by a great many Cu 2O nanoparticles. The photocatalytic performance of Cu 2O/TiO 2 nanocomposite was evaluated by the photodegradation of methylene blue (MB) under visible light, and compared with those of the pure TiO 2 and Cu 2O photocatalysts synthesized by the identical synthetic route. Within 120 min of reaction time, nearly 100% decolorization efficiency of MB was achieved by Cu 2O/TiO 2 photocatalyst, which is much higher than that of pure TiO 2 (26%) or Cu 2O (32%). The outstanding photocatalytic efficiency was mainly ascribed to the unique architecture, the extended photoresponse range and efficient separation of the electron-hole pairs in the Cu 2O/TiO 2 heterojunction. In addition, the Cu 2O/TiO 2 nanocomposite also retains good cycling stability in the photodegradation of MB. 相似文献
4.
A series of novel ZnO/Ag/Ag 2WO 4/AgI nanocomposites have been successfully synthesized by a facile ultrasonic-irradiation method and their photocatalytic activities were explored under visible-light illumination using rhodamine B. The synthesized nanocomposites were characterized by various techniques to determine their structural, morphological, and electronical properties. Effect of the amount of AgI, as visible-light sensitizer, on the photocatalytic activity was studied and it was found that the nanocomposite with 30% of AgI displayed the highest photocatalytic activity. Activity of this photocatalyst was almost 150, 17.8, and 55.1 times greater than those of the ZnO, ZnO/Ag/Ag 2WO 4, and ZnO/AgI photocatalysts, respectively. Besides, the importance of active species during the degradation process was explored and it was shown that superoxide anion radical has major role in the photodegradation reaction. Moreover, the outstanding performance of the best nanocomposite in degradations of three more dye pollutants was confirmed. Finally, a cascade mechanism was proposed for the greatly enhanced activity of the nanocomposites in degradation reactions. 相似文献
5.
The present work aimed to synthesize Zn 0.95Ag 0.05O (ZnAgO) nanoparticles using rosemary leaf extracts as a green chemistry method. The characterization of Ag-doped ZnO nanoparticles was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectrophotometry (UV–visible). The XRD, FTIR, and UV–visible spectra confirmed the formation of the presence of hexagonal ZnAgO nanoparticles. FESEM micrograph shows that the nanoparticles have been distributed homogeneously and uniformly. The morphology of ZnAgO nanoparticles is quasi-spherical configuration. Also, the mean particle size is in the range of 22–40 nm. The photocatalytic degradation of methylene blue in the presence of Ag-doped ZnO nanoparticles is nearly 98.5% after exposing 100 min. The ultraviolet lamp was used as the light source for photocatalyst degradation. The disc diffusion method was chosen to study the antibacterial activity of as-synthesized ZnAgO nanoparticles. Antibacterial activity of Zn 0.95Ag 0.05O nanoparticles against Staphylococcus aureus and Escherichia coli revealed that the as-synthesized ZnAgO nanoparticles were efficient in inhibition of bacterial growth. 相似文献
6.
In order to compare the photocatalytic properties of TiO 2, ZnO and their composite in the gas phase pollutant environment, nanocomposite with different mole ratios of TiO 2/ZnO were designed to degrade gaseous formaldehyde. The results showed that the rate constant of TiO 2 for formaldehyde degradation was 0.05 min ?1 which was two orders of magnitude larger than that of ZnO in our experiment. Through comprehensive analysis of UV–vis diffuse reflectance (UV–vis) spectra, photoluminescence spectra (PL) and energy band diagram, it was found that the differences of photocatalytic properties between ZnO and TiO 2 may mainly originate from the increased recombination of photoinduced charges in ZnO. The photocatalytic properties of TiO 2/ZnO composite for formaldehyde degradation were much worse than those of TiO 2, while better than those of ZnO. The addition of a small amount of ZnO weakened the photocatalytic properties of TiO 2. It may be attributed to that the recombination action of photoinduced electron–hole pairs in ZnO. 相似文献
7.
A new type of photodegradable poly(vinyl chloride)‐bismuth oxyiodide/TiO 2 (PVC‐BiOI/TiO 2) nanocomposite film was prepared by embedding a nano‐TiO 2 photocatalyst modified by BiOI into the commercial PVC plastic. The solid‐phase photocatalytic degradation behavior of the as‐prepared film was investigated in ambient air at room temperature under UV light irradiation, with the aid of UV‐Vis spectroscopy, weight loss monitoring, scanning electron microscopy, and FT‐IR spectroscopy. Compared to the PVC‐TiO 2 nanocomposite film, the PVC‐BiOI nanocomposite film and the pure PVC film, the PVC‐BiOI/TiO 2 nanocomposite film exhibited a higher photocatalytic degradation activity. The optimal mass ratio of BiOI to TiO 2 was found to be 0.75 %. The weight loss rate of the PVC‐BiOI/TiO 2 nanocomposite film reached 30.8 % after 336 h of irradiation, which is 1.5 times higher than that of the PVC‐TiO 2 nanocomposite film under identical conditions. The solid‐phase photocatalytic degradation mechanism of the nanocomposite films was briefly discussed. 相似文献
8.
Rational design of semiconductor membrane photocatalyst with good mechanical flexibility and excellent photocatalytic activity is of significance for environmental remediation. Herein, flexible Ag@ZnO/TiO 2 fibrous membranes with hierarchical nanostructures were fabricated through combining a simple electrospinning method and subsequent hydrothermal reaction and photodeposition process. In the ternary nanocomposite, ZnO nanorods were firmly anchored onto TiO 2 nanofibers, while Ag nanoparticles were evenly decorated on the surface of both ZnO and TiO 2. Benefiting from the improved light absorption, large surface area, and effective charge separation, the resultant Ag@ZnO/TiO 2 membranes displayed superior photocatalytic degradation efficiency of 91.6% toward tetracycline hydrochloride within 1 h, and also exhibited prominent antibacterial activity with a 6.5 log inactivation of E. coli after 1 h simulated solar light exposure. Significantly, the membrane photocatalyst still preserved structural integrity and mechanical flexibility after utilization. This study provides an alternative approach for designing and synthesizing flexible TiO 2-based membrane photocatalysts toward high-efficiency water purification. 相似文献
9.
Visible-light-induced titania/sulfanilic acid nano-composite photocatalysts were prepared and characterized by FTIR, XPS, UV-vis, XRD, and SEM. The results indicate that the formation of Ti-O-S bonds after the modification of P25 TiO 2 nanoparticles with sulfanilic acid ligands extends the photoresponse of the photocatalyst from the UV to the visible range. The photocatalytic activity of the nano-composite photocatalyst was examined by degrading Congo red under visible light, in which its effecting factors such as irradiation time, catalyst dosage, solution pH and the addition of H 2O 2, were investigated in detail. The possible mechanism of photocatalytic degradation under visible irradiation has been also presented. 相似文献
10.
Photocatalytic reduction of carbon dioxide (CO 2) into valuable hydrocarbon such as methane (CH 4) using water as reducing agent is a good strategy for environment and energy applications. In this study, a facile and simple sol-gel method was employed for the synthesis of metal (Cu and Ag) loaded nanosized N/TiO 2 photocatalyst. The prepared photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, BET Surface area analyzer, X-ray photoelectron spectroscopy and UV–vis diffuses reflectance spectroscopy. The photocatalytic conversion of CO 2 into methane was carried out under visible light irradiation (λ≥420 nm) by prepared photocatalysts in order to evaluate the photocatalytic efficiency. The results demonstrate that Ag loaded N/TiO 2 showed enhanced photocatalytic performance for methane production from CO 2 compared to other Cu–N/TiO 2, N/TiO 2 and TiO 2 photocatalysts. The improvement in the photocatalytic activity could be attributed to high specific surface area, extended visible light absorption and suppressed recombination of electron – hole pair due to synergistic effects of silver and nitrogen in the Ag–N/TiO 2 photocatalyst. This study demonstrates that Ag–N/TiO 2 is a promising photocatalytic material for photocatalytic reduction of CO 2 into hydrocarbons under visible light irradiation. 相似文献
11.
A novel Cu 2O/TiO 2/Bi 2O 3 ternary nanocomposite was prepared, in which copper oxide improves the visible light absorption of TiO 2 and bismuth oxide improves electron–hole separation. The ternary composite exhibited extended absorption in the visible region, as determined by UV–Vis diffuse reflectance spectroscopy. High-resolution transmission electron microscopy images showed close contact among the individual semiconductor oxides in the ternary Cu 2O/TiO 2/Bi 2O 3 nanocomposite. Improved charge carrier separation and transport were observed in the Cu 2O/TiO 2/Bi 2O 3 ternary composite using electrochemical impedance spectroscopy and photocurrent analysis. TiO 2 modified with bismuth and copper oxides showed exceptional photocatalytic activity for hydrogen production under natural solar light. With optimum bismuth and copper oxide loadings, the Cu 2O/TiO 2/Bi 2O 3 ternary nanocomposite exhibited an H 2 production (3678 μmol/h) 35 times higher than that of bare TiO 2 (105?μmol/h). The synergistic effect of improved visible absorption and minimal recombination was responsible for the enhanced performance of the as-synthesized ternary nanocomposite. 相似文献
12.
AbstractToday, the ultrasound utilizing for material synthesis has been extensively investigated. The unusual acoustic cavitation phenomenon caused by ultrasonic waves has created a new world for the production of high efficiency photocatalysts with new structures. In this study, TiO 2, TiO 2-Ag, and TiO 2-ZnO thin film photocatalysts were prepared using titanium isopropoxide Ti[OCH(CH 3) 2] 4, zinc acetate dehydrates (CH 3COO) 2Zn·2H 2O, and silver nitrate AgNO 3 by a sol–gel method under the ultrasonic irradiation. The prepared photocatalysts were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive spectroscopy. The SEM images showed that the Ag and ZnO particles were evenly dispersed in the photocatalysts due to the ultrasonic irradiation, and Ag particles were approximately 90?nm, which is relatively small compared to the photocatalysts which is not treated with ultrasonic irradiation. The catalytic activity of the photocatalysts was determined using Acid Red 27 dye. The most excellent catalytic degradation was obtained with TiO 2-ZnO thin film photocatalyst. In comparison to the conventional photocatalyst, the efficiency of photocatalytic activity of the photocatalyst produced under ultrasonication has been increased due to the reduced size of Ag and ZnO and its uniform dispersion. 相似文献
13.
Cu 2O/TiO 2 composite nanotube arrays demonstrating enhanced photocatalytic performance were synthesized using an electrodeposition method to impregnate the p-type Cu 2O into the n-type titanium dioxide nanotube arrays (TNTs). The morphological results confirmed that the TNTs are wrapped by the Cu 2O nanoparticles and the UV–Vis absorption spectra showed that the Cu 2O/TNTs display a better ability for visible light absorption compared to the pure TNTs. CO 2 photocatalytic reduction experiments carried out by using Cu 2O/TNT nanocomposites proved that Cu 2O/TNTs exhibit high photocatalytic activity in conversion of CO 2 to methanol, while pure TNT arrays were almost inactive. Furthermore, Cu 2O/TNTs also exhibited augmented activity in degradation of target organic pollutant like acid orange (AO) under visible light irradiation. The ultra enhanced photocatalytic activity noticed by using Cu 2O/TNTs in CO 2 reduction and degradation of organic pollutant could be attributed to the formation of Cu 2O/TiO 2 heterostructures with higher charge separation efficiency. 相似文献
14.
A TiO 2–nanoclay nanocomposite was used as a photocatalyst for the degradation of phenol in presence of acoustic cavitation. TiO 2–nanoclay nanocomposite was synthesised in benzyl alcohol medium wherein TiO 2 nanoparticles were formed between the nanoclay platelets. The synthesised product was characterised by using FTIR, XRD and TEM techniques. TEM image shows that TiO 2–nanoclay nanocomposite particles were in the range of 30–40 nm. XRD gram confirms the formation of nanocomposite of TiO 2 nanoclay. The effect of cavitation and TiO 2–nanoclay nanocomposite photocatalyst on phenol removal was investigated. The effects of various parameters such as nanocomposite loading, initial concentration, etc., have been studied. On comparing the results obtained with that of nanocomposite without UV, it was found for an initial concentration of 500 mg/L of phenol, the TiO 2–nanoclay nanocomposite exhibited higher percentage of pollutant removal (59%) and for nanoclay it was 47%. © 2011 Canadian Society for Chemical Engineering 相似文献
15.
Here, novel graphene/TiO 2 nanocomposite has been successfully prepared by loading flocculent-like titanate nanostructure in graphene sheets via hydrothermal method plus a subsequent annealing process. The as-obtained hybrid was characterized by X-ray diffraction, scanning electron microscopy with an energy dispersive spectroscope (EDS), Raman, and UV–vis diffuse reflectance spectra, respectively. The photoelectrochemical activities and photocatalytic degradation performance of methyl orange under the illumination of ultraviolet light were investigated, and the flocculent-like TiO 2/graphene composites was found to have a superior photocatalytic activity compared to flocculent-like titanate nanostructure and commercial anatase TiO 2 powder, which can be attributed to the improved light absorption and extremely efficient charge separation of the hybrid structure. The results suggest that the as-prepared flocculent-like TiO 2/graphene composite is a promising photocatalyst for photoelectrochemical hydrogen production and pollution removal. 相似文献
16.
Ag 2O modified TiO 2 nanoparticles were synthesized by precipitation and wet impregnation method. They were characterized by X-ray diffraction technique, UV-vis diffuse reflectance spectrophotometry and Fourier transform infrared spectroscopy. Inductively coupled plasma mass spectrometry was performed to quantify Ag amount in the photocatalysts. The photocatalysts occurred in the concentration range of 0.05%–2% in the Ag/Ti molar ratio. The photocatalytic activity was investigated for the degradation of methylene blue as a model organic dye. Optimum reaction conditions were determined to provide maximum dye degradation efficiencies under visible light. Under visible light illumination, C2-Ag 2O/TiO 2 (Ag/Ti = 0.1/100) showed the highest activity. Reaction rate constants were calculated and compared for various reaction conditions. 相似文献
17.
This work explores the effect of ternary nanostructure for the enhanced photocatalytic degradation of pollutants and dyes. One-pot solvothermal-assisted approach was used for producing nanosized Pt@TiO2 hybrid nanoparticles (NPs) decorated on reduced graphene oxide (rGO) layers. The microstructure, morphology, chemical composition, and optical absorption of the designed photocatalyst was successfully characterized (using XRD, TEM, Raman, UV–visible absorption spectra, and XPS techniques). The ternary Pt@TiO2-rGO photocatalyst consist of monodisperse quasi-spherical Pt@TiO2 NPs with an average size of 11 nm deposited on the rGO nanosheets. Furthermore, Pt@TiO2-rGO was further investigated for the photodegradation of pesticide and dyes under UV and visible light. The ternary Pt@TiO2-rGO photocatalyst proved a significant improvement on the photodecomposition of pollutants compared to hybrid Pt@TiO2. The Pt@TiO2-rGO photocatalyst was found to show seven- and threefold increase in the photocatalytic activity compared to TiO2 and Pt@TiO2 NPs, respectively which resulted from the high surface area of rGO and as well as the strong Pt/TiO2/rGO interactions which ensured excellent properties of charge separation. On the other hand, the ternary photocatalyst exhibited very good recycle and reuse capacity up to five cycles. 相似文献
18.
Approximately 47% of solar-terrestrial radiation is visible. It is a great achievement to produce a highly efficient visible driven photocatalyst. Here TiO 2/NiS 2/Cu nanocomposite was prepared as a highly active visible driven photocatalyst. TiO 2/NiS 2/Cu nanocomposite was prepared by microwave method. It degrades 92%, 86%, 87%, and 88% of Rhodamine B (RhB), Methyl orange (MO), Acid Black 1 (AB1), and Acid Brown 214 (AB214), respectively. Adding NiS 2 and Cu to TiO 2 dramatically increased the degradation efficiency from 17% for bare TiO 2 to 92% for TiO 2/NiS 2/Cu nanocomposite under visible light. As-prepared TiO 2/NiS 2/Cu nanocomposite was characterized by SEM, TEM, XRD, DRS, BET, and EDX. 相似文献
19.
In this paper, a series of CdS/TiO 2 NTs have been synthesized by SILAR method. The as-prepared CdS/TiO 2 NTs have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and ultraviolet–visible (UV–vis). And their photocatalytic activities have been investigated on the degradation of methylene blue under simulated solar light irradiation. XRD results indicate that TiO 2 NTs were anatase phase, CdS nanoparticles were hexagonal phase. FESEM results indicate that low deposition concentration can keep the nanotubular structures. UV–vis results indicate that CdS can be used to improve the absorbing capability of TiO 2 NTs for visible light, and the content of CdS affects the band gap. Photocatalytic results indicate that CdS nanoparticles are conducive to improve the photocatalytic efficiency of TiO 2 NTs, and the highest degradation rate can reach 93.8%. And the photocatalytic mechanism of CdS/TiO 2 NTs to methylene blue is also described. 相似文献
20.
The design and construction of efficient visible light responsive composite photocatalysts with intimate interfacial contacts in photocatalytic field have attracted huge interest. Herein, a double-shelled ZnIn 2S 4 nanosheets/TiO 2 hollow composite single nanosphere (ZIS/TiO 2) was first fabricated by a facile hydrothermal process, where 2D ZnIn 2S 4 nanosheets self-assembled on the external surface of TiO 2 hollow nanosphere to form the double-shelled hollow single sphere. The morphologies, structures, optical properties of as-prepared double-shelled ZIS/TiO 2 hollow nanospheres were characterized in detail. The photocatalytic activities of double-shelled ZIS/TiO 2 nanospheres for the photodegradations of Tetracycline hydrochloride, Levofloxacin and Rhodamine B under visible light irradiation have been investigated. Compared to pure TiO 2 and ZnIn 2S 4, the obtained ZIS/TiO 2 samples have significantly improved photocatalytic performances. The most optimal photocatalytic activity of ZIS/TiO 2-2 nanocomposite with 64 wt% ZnIn 2S 4 nanosheets coated is observed, and its degradation rate constant is 2.32 and 2.14 times as high as those of pure TiO 2 and ZnIn 2S 4. The superior photocatalytic performance of ZIS/TiO 2 nanocomposite can be ascribed to its unique double shell hollow structure and the synergistic effect between ZnIn 2S 4 and TiO 2. Our result provides some guidance for designing novel morphologies of composite photocatalyst with good photocatalytic performance. 相似文献
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