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1.
Visible light active Ag doped SnO2 nanoparticles modified with curcumin (Cur–Ag–SnO2) have been prepared by a combined precipitation and chemical impregnation route. The optical properties, phase structures and morphologies of the as-prepared nanoparticles were characterized using UV–visible diffuse reflectance spectra (UV–vis-DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The surface area was measured by Brunauer. Emmett. Teller (B.E.T) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag–SnO2 and Cur–Ag–SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Cur–Ag–SnO2 shows better photocatalytic activity than that of Ag–SnO2 and SnO2. The superior photocatalytic activity of Cur–Ag–SnO2 could be attributed to the effective electron-hole separation by surface modification. The effect of photocatalyst concentration, initial dye concentration and electron scavenger on the photocatalytic activity was examined in detail. Furthermore, the antifungal activity of the photocatalysts and the reusability of Cur–Ag–SnO2 were tested.  相似文献   

2.
ZnO–SnO2 nanoparticles were prepared by coprecipitation method; then Mg, with different molar ratios and calcination temperatures, was loaded on the coupled nanoparticles by impregnation method. The synthesized nanoparticles were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) techniques. Based on XRD results, the ZnO–SnO2 and Mg/ZnO–SnO2 nanoparticles were made of ZnO and SnO2 nanocrystallites. According to DRS spectra, the band gap energy value of 3.13 and 3.18 eV were obtained for ZnO–SnO2 and Mg/ZnO–SnO2 nanoparticles, respectively. BET analysis revealed a Type III isotherm with a microporous structure and surface area of 32.051 and 49.065 m2 g?1 for ZnO–SnO2 and Mg/ZnO–SnO2, respectively. Also, the spherical shape of nanocrystallites was deduced from TEM and FESEM images. The photocatalytic performance of pure ZnO–SnO2 and Mg/ZnO–SnO2 was analyzed in the photocatalytic removal of methyl orange (MO). The results indicated that Mg/ZnO–SnO2 exhibited superior photocatalytic activity to bare ZnO–SnO2 photocatalyst due to high surface area, increased MO adsorption and larger band gap energy. Maximum photocatalytic activity of Mg/ZnO–SnO2 nanoparticles was obtained with 0.8 mol% Mg and calcination temperature of 350°C.  相似文献   

3.
Bare TiO2 and Cu-doped TiO2 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 TiO2 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 TiO2 photocatalyst compared to bare TiO2 . The enhanced photocatalytic performance arises from copper ion doping in the TiO2 structure, leading to an extended photoresponsive range, enhanced photogenerated charge separation, and transportation efficiency.  相似文献   

4.
ZnO doped SnO2 has been successfully synthesized by the solvothermal method using methanol as organic solvent. The effect of ZnO/SnO2 molar ratios on the crystal structure, microstructure, optical and photocatalytic properties has been investigated. The synthesized samples are characterized by X-ray diffraction, transmission electron microscopy, N2 physical adsorption, FT-IR spectroscopy and UV–Vis spectroscopy. XRD results revealed that all diffraction peaks positions agree well with the reflection of a tetragonal rutile structure of SnO2 phase without extra peaks at 0.1ZnO:0.9SnO2 and 0.2ZnO:0.8SnO2 molar ratios. However, the secondary phase of ZnO at 0.3ZnO:0.7SnO2 molar ratio was investigated. TEM images revealed that the shape of SnO2 particles was spherical and the particle sizes of SnO2 and 0.3ZnO:0.7SnO2 molar ratio were 6.2 and 16.4 nm, respectively. The newly prepared samples have been tested by the determination of photocatalytic degradation of methylene blue (MB). The results indicated that Zn2+ doping at 0.3ZnO:0.7 SnO2 molar ratio showed the highest photocatalytic activity for the MB photodegradation. The heightened photocatalytic activity of ZnO/SnO2 could be ascribed to the enhanced charge separation derived from the coupling of ZnO with SnO2 due to the potential energy differences between SnO2 and ZnO. The recycling tests demonstrated that 0.3ZnO:0.7 SnO2 photocatalysts were quite stable during that liquid–solid heterogeneous photocatalysis since no decrease in activity in the first four cycles was observed.  相似文献   

5.
Sulfur and copper codoped TiO2 nanoparticles were prepared by sol-hydrothermal process. And the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra analysis, scanning electron microscopy, Brunauer Emmett Teller analysis, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectra and X-ray fluorescence analysis. It was found that the S, Cu-codoped TiO2 became amorphous with the increase of Cu content, and copper on the surface of TiO2 existed in the oxidation state of Cu(II) while S in the form of S6+ species. And the codoped particles had higher surface area, smaller particle size, stronger spectral response in visible region compared with pure TiO2. The effects of doping amount in a wide range, catalyst dosage, and recycle on the photocatalytic activity of the codoped catalysts were investigated with Acid Orange 7 as the model compound under visible light illumination (λ > 447 nm). The results showed that S (2.0 %), Cu (5.0 %) codoped TiO2 had the highest visible light photocatalytic activity and good reusability performance. The kinetic study showed that this photocatalytic process coincided with the Langmuir–Hinshelwood pseudo first order reaction model.  相似文献   

6.
A plasma-assisted synthesis of TiO2/SnO2 nanocomposite is described. In this approach, a precursor containing a mixture of [TiCl3 and SnCl2] exposed to electric discharge was oxidized by plasma-generated reactive species (HO·/H2O = 2.85 eV/SHE). SnO2 microstructures with a diameter of 10–40 µm were coated by thin layers TiO2 nanorods with mean diameter of 6–8 nm. The obtained TiO2/SnO2 nanocomposite was characterized by transmission and scanning electron microscopy, X-ray diffraction and Fourier transform infrared. TiO2/SnO2 nanocomposite was found to be a promising new material for the photocatalytic discoloration of aqueous Remazol Brilliant Blue-R dye under daylight and UVA light sources, due to the combined effects of large specific surface area and heterojunction which efficiently separates the electron–hole pairs delaying the charge recombination. The leaching test indicated that the nanocomposite is stable easily reusable.  相似文献   

7.
ZnFe2O4 nanoparticles sensitized by C-modified TiO2 hybrids (ZnFe2O4–TiO2/C) were successfully prepared by a feasible method. The ZnFe2O4 nanoparticles were prepared by mechanical alloying and annealing. The residual organic compounds in the synthetic process of TiO2 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 N2 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 TiO2 lattice but adhered to the surface of TiO2. The photocatalytic activity of the as-prepared C-modified TiO2 (TiO2/C) improved both under UV and simulated solar light irradiation, but the improvement was not dramatic. Introduction of ZnFe2O4 into the TiO2/C could enhance the absorption spectrum range. The ZnFe2O4–TiO2/C hybrids exhibited a higher photocatalytic activity both than that of the pure TiO2 and TiO2/C under either UV or simulated solar light irradiation. The complex synergistic effect plays an important role in improving the photocatalytic performance of ZnFe2O4–TiO2/C composites. The optimum photocatalytic performance was obtained from the ZnFe2O4(0.8 wt%)–TiO2/C sample.  相似文献   

8.
《化学:亚洲杂志》2017,12(19):2597-2603
In this paper, an Ag‐doped WO3 (and MoO3) composite has been prepared by following a simple micelle‐directed method and high‐temperature sintering route. The as‐prepared samples were characterized by X‐ray diffraction, inductively coupled plasma, transmission electron microscopy, X‐ray photoelectron spectroscopy, UV/Vis diffuse reflectance spectroscopy, Brunauer–Emmett–Teller, photoluminescence spectroscopy, and electrochemical impedance spectroscopy techniques. The photocatalytic experiments reveal that their oxygen‐production rates are up to 95.43 μmol (75.45 μmol) for Ag‐doped WO3 (MoO3), which is 9.5 (7.3) times higher than that of pure WO3: 9.012 μmol (MoO3: 9.00 μmol) under visible‐light illumination (λ ≥420 nm), respectively. The improvement of their photocatalytic activity is attributed to the enhancement of their visible‐light absorption and the separation efficiency of photogenerated carriers by Ag doping. Moreover, Ag‐doped WO3 (MoO3) also shows excellent adsorption of rhodamine B (RhB) and methylene blue (MB) in aqueous solution, with maximum adsorption capacities towards RhB and MB of 822 and 820 mg g−1 for Ag‐doped WO3, and 642 and 805 mg g−1 for Ag‐doped MoO3, respectively.  相似文献   

9.
Pure phase ZnTiO3 was prepared through a sol–gel process, then graphene-ZnTiO3 nanocomposites were synthesized by a hydrothermal method using the prepared ZnTiO3 nanoparticles and graphene oxide as precursors. X-ray diffraction results revealed the production of pure cubic ZnTiO3 at 600 °C. ZnTiO3 was anchored on the graphene nanosheets, demonstrating a spherical morphology in transmission electron microscope images. The existence of chemical bond Ti–O–C in the nanocomposites was proved by Fourier-transforming infrared spectroscopy. UV–Vis diffusive reflection spectra indicated that the absorption edge of the nanocomposites shifted towards the visible region. The photocatalytic activity of the composites was tested through the photocatalytic degradation of methyl blue under simulated solar irradiation. The results showed that the photocatalytic activity of the nanocomposites was obviously increased in contrast to pure ZnTiO3, which was strongly affected by the crystalline structure of ZnTiO3 and the concentration of graphene. The enhanced photocatalytic activity was mainly attributed to the conglomeration inhibition of ZnTiO3 nanoparticles, the electron transfer between ZnTiO3 and graphene and the extended absorption range. Furthermore, other contaminants such as tetracycline, Rhodamine B and methyl orange were tested under the same conditions to investigate the photocatalytic performance of the photocatalysts. The reusability tests indicated that the prepared composites exhibited good stability.  相似文献   

10.
The reduced graphene oxide‐Bi2WO6 (rGO‐BWO) photocatalysts with the different RF/O values (molar ratio of the F molar mass and the O's molar mass of Bi2WO6) 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 RF/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 RF/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   

11.
SnO2–TiO2/fly ash cenospheres (FAC) were prepared via hydrothermal method and used as an active photocatalyst in a photocatalytic system. Scanning electron microscopy, X‐ray diffraction analysis, UV–Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy and N2 adsorption–desorption measurements were used to determine the structure and optical property of SnO2–TiO2/FAC. Phenol was selected as the model substance for photocatalytic reactions to evaluate catalytic ability. Results showed that the degradation efficiency of phenol by SnO2–TiO2/FAC was 90.7% higher than that decomposed by TiO2/FAC. Increased efficiency could be due to the enhanced synergistic effect of semiconductors and FAC could provide more adsorption sites for the pollutant in the photocatalytic reaction. Furthermore, SnO2–TiO2/FAC composites exhibited excellent photocatalytic stability in four reuse cycles. Radical‐trapping experiments further revealed the dominating functions of holes in the photocatalytic reaction.  相似文献   

12.
AgBr@TiO2/GO (graphene oxide) ternary composite photocatalyst was synthesized by fabricating core–shell-structured AgBr@TiO2 and anchoring it onto the surface of GO. The obtained samples were characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, ultraviolet–visible (UV–Vis) diffuse reflectance spectrum, and photoluminescence (PL) spectroscopy. It was found that the AgBr nanoparticles were prone to aggregation while the core–shell-structured AgBr@TiO2 possessed excellent dispersity. PL analysis revealed that the ternary-structured AgBr@TiO2/GO could effectively promote the separation rate of electron–hole pairs. Photocatalytic oxidation of benzyl alcohol to benzaldehyde under visible-light irradiation was selected as probe reaction to evaluate the photocatalytic activity of the different samples. It was found that the AgBr@TiO2/GO ternary composite exhibited evidently improved photocatalytic activity compared with AgBr, AgBr@TiO2, and AgBr/GO. On the basis of the experiment results, the photocatalytic oxidation mechanism of benzyl alcohol over AgBr@TiO2/GO is tentatively discussed.  相似文献   

13.
In3+-doped BiVO4 nanoparticles with enhanced visible light activity have been successfully synthesized by a hydrothermal method. The synthesized materials were characterized by X-ray diffraction, Raman, X-ray photoelectron spectroscopy, scanning electron microscopy, BET surface areas analysis, and ultraviolet–visible diffuse reflectance spectra. In comparison with pure BiVO4, the In3+-doped BiVO4 displayed greater photocatalytic activity in the degradation of methyl blue under visible light illumination. All samples possessed a single monoclinic structure. The introduction of In ions resulted in structural distortion and the decreased band gap energy, producing more electrons and holes for photocatalytic reaction. In the meantime, the doping In ions entails a red shift in the absorption edge and an increase in the intensity of light absorption. The best photocatalytic performance was obtained with the BiVO4 sample containing 5.0 mol% In ions.  相似文献   

14.
In this work, a nitrogen-doped anatase TiO2 nanocrystal is prepared by a modified sol-gel preparation method using the nonionic surfactant (polyoxyethylene sorbitan monooleate) as a structural controller and a soft template. The as-prepared samples are characterized by X-ray diffraction, Raman spectroscopy, UVVis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy techniques. Then the photocatalytic activity of these samples is assessed by the photocatalytic oxidation of phenol under visible light irradiation. The phenol concentration is measured using a UV-Vis spectrometer. Experimental results show that N-doping leads to an excellent visible light photocatalytic activity of the TiO2 nanocatalyst. Furthermore, the formation energy and electronic structure of pure and N-doped anatase TiO2 are described by density functional theory (DFT) calculations. It is found that N-doping narrowed the band gap of bare TiO2, which leads to an excellent visible light photocatalytic activity of N–TiO2 nanocatalysts. Therefore, the prepared N–TiO2 photocatalyst is expected to find the use in organic pollutant degradation under solar light illumination.  相似文献   

15.
Orthorhombic MoO3 and W-doped MoO3 nanobelts were successfully synthesized by a hydrothermal method. The effect of W dopant on the photocatalytic performance of W-doped MoO3 nanobelts was studied. The phase, morphology, and oxidation state of the products were characterized by X-ray diffraction analysis, Fourier-transform infrared and Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. In this research, MoO3 and W-doped MoO3 exhibited the same phase and morphology of orthorhombic nanobelts with growth along the [001] direction, including detection of Mo6+, O2?, and W6+ in the 3 mol% W-doped MoO3 sample. The photocatalytic performance of the as-synthesized MoO3 and W-doped MoO3 nanobelts was monitored through photodegradation of methylene blue (MB) under visible radiation. W-doped MoO3 nanobelts showed better photocatalytic performance than pure MoO3. The 3 mol% W-doped MoO3 photocatalyst exhibited very good visible-light-driven activity for photodegradation of MB, as high as 99 % within 60 min.  相似文献   

16.
Nanosized TiO2 and nano-anatase TiO2 decorated on SiO2 spherical core shells were synthesized by using a sol–gel method. The synthesized pure TiO2 nano particle and TiO2 grafted on SiO2 sphere with various ratios have been characterized for their structure and morphologies by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrophotometry (FTIR) and transmission electron microscopy (TEM). Their surface areas were measured using the BET method. The photocatalytic activity of all nanocomposites was investigated using methylene blue as a model pollutant. The synthesized TiO2/SiO2 particles appeared to be more efficient in the degradation of methylene blue pollutant, as compared to pure TiO2 particles.  相似文献   

17.
The preparation of a carbon ceramic electrode modified with SnO2 (CCE/SnO2) using tin dibutyl diacetate as precursor was optimized by a 23 factorial design. The factors analyzed were catalyst (HCl), graphite/organic precursor ratio, and inorganic precursor (dibutyltin diacetate). The statistical treatment of the data showed that only the second-order interaction effect, catalyst × inorganic precursor, was significant at 95% confidence level, for the electrochemical response of the system. The obtained material was characterized by scanning electron microscopy (MEV), X-ray diffraction (XRD), RAMAN spectroscopy, XPS spectra, and voltammetric techniques. From the XPS spectra, it was confirmed the formation of the Si–O–Sn bond by the shift in the binding energy values referred to Sn 3d3/2 due to the interaction of Sn with SiOH species. The incorporation of SnO2 provided an increment of the electrode response for levofloxacin, with Ipa = 147.0 μA for the ECC and Ipa = 228.8 μA for ECC/SnO2, indicating that SnO2 when incorporated into the silica network enhances the electron transfer process. Under the optimized working conditions, the peak current increased linearly with the levofloxacin concentration in the range from 6.21×10?5 to 6.97×10?4 mol L?1 with quantification and detection limits of 3.80×10?5 mol L?1 (14.07 mg L?1) and 1.13×10?5 mol L?1 (4.18 mg L?1), respectively.  相似文献   

18.
new material of Cu(OH)2 nanostructures was prepared using cupric nitrate and sodium hydroxide as raw materials by the chemical precipitation method. The Cu(OH)2 nanostructures were characterized by scanning electron microscope, transmission electron microscopy, infrared spectrometer, and X-ray diffractometer. The results showed that the Cu(OH)2 nanostructures exhibited excellent uniform and dispersion at 40°C. A series of factors was investigated to effect the photocatalytic efficiency of methyl orange (MO), such as the concentration of Cu(OH)2 nanostructures, the reaction time of the Cu(OH)2 nanostructures, the initial concentration of MO, and so on. As a result, the Cu(OH)2 nanostructures exhibited excellent photocatalytic efficiency with the concentration of 20 mg L–1 Cu(OH)2 nanostructures, the initial concentration of MO was 15 mg L–1 and the stirring time was 70 min.  相似文献   

19.
NiS/TiO2 nano-sheet films (NiS/TiO2 NSFs) photocatalysts were prepared by loading NiS nanoparticles as noble metal-free cocatalysts on the surface of TiO2 films through a solvothermal method. The prepared samples were characterized by XRD, SEM, EDS, UV–Vis absorption spectra and XPS analysis. The photocatalytic H2 evolution and photoluminescence spectroscopy (PL) experiments indicated that the NiS cocatalysts could efficiently promote the separation of photogenerated charge carriers in TiO2 and consequently enhance the H2 evolution activity. The hydrogen yield obtained from the optimal sample reached 4.31 μmol cm–2 at 3.0 h and the corresponding energy efficiency was about 0.26%, which was 21 times higher than that of pure TiO2 NSF. A possible photocatalytic mechanism of NiS cocatalyst on the improvement of the photocatalytic performance of TiO2 NSF was also proposed.  相似文献   

20.
In this work, a facile ultrasonic-assisted method was applied for preparation of Fe3O4/Ag3VO4 nanocomposites with different compositions. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive analysis of X-rays, UV–Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometery. Photocatalytic degradation of rhodamine B under visible-light irradiation was investigated, and it was found that weight ratio of Fe3O4–Ag3VO4 has significant influence on the photocatalytic activity and the nanocomposite with 1:4 weight ratio of Fe3O4–Ag3VO4 has superior activity. In addition, the nanocomposite showed great activities in degradations of methylene blue and fuchsine, which are comparable with activity of the pure Ag3VO4. More importantly, this nanocomposite displayed remarkable saturation magnetization, leading to easily and quickly separation of its suspension from treated system by applying a magnetic field.  相似文献   

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