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1.
N-doped NaTaO 3 catalysts were synthesized via a sol–gel method followed by a subsequent calcination process under NH 3 atmosphere. The as prepared samples were characterized by XPS, XRD, UV–Vis DRS, and BET analyses. All XRD peaks of the sample calcined at 900 °C matched with pure perovskite NaTaO 3 while peaks of TaON and Na 2Ta 4O 11 were found for that calcined at 1,000 °C. The DRS of samples shown cutoff edge has red shifted, from 315 nm of pure to 391 nm of N-doped NaTaO 3. N-doping helps to narrow the band gap, and the prepared sample was visible light sensitive. The XPS spectrum of Ta4 p3&N1 s shown two new peaks at 398.3 and 401.4 eV appear in the N-doped sample corresponding to Ta–N bonds and adsorption nitride, respectively. Photocatalytic activity of the catalysts was evaluated using Rhodamine B dye. The result demonstrated that the sample calcined under NH 3 had a higher photocatalytic activity than that of P25 under visible light. The NaTaO 3/TaON heterojunction played an important role on promoting photoactivity. 相似文献
2.
Novel visible-light-induced photocatalysts were fabricated by integration of Ag 3VO 4 and AgBr semiconductors with graphitic carbon nitride (g-C 3N 4) through a facile refluxing method. The fabricated photocatalysts were extensively characterized by XRD, EDX, SEM, TEM, FT-IR, UV–vis DRS, BET, TGA, and PL instruments. The photocatalytic performance of these samples was studied by degradations of three dye contaminants under visible-light exposure. Among the ternary photocatalysts, the g-C 3N 4/Ag 3VO 4/AgBr (10%) nanocomposite displayed the maximum activity for RhB degradation with rate constant of 1366.6 × 10 −4 min −1, which is 116, 7.23, and 38.5 times as high as those of the g-C 3N 4, g-C 3N 4/AgBr (10%), and g-C 3N 4/Ag 3VO 4 (30%) photocatalysts, respectively. The effects of synthesis time and calcination temperature were also investigated and discussed. Furthermore, according to the trapping experiments, it was found that superoxide anion radicals were the predominant reactive species in this system. Finally, the ternary photocatalyst displayed superlative activity in removal of the contaminants under visible-light exposure, displaying great potential of this ternary photocatalyst for environmental remediation, because of a facile synthesis route and outstanding photocatalytic performance. 相似文献
3.
采用简单固相法成功制备了CeTiO 4/g?C 3N 4?x(CTO/CN?x,x g为g?C 3N 4的添加量)复合材料,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、N 2吸附-脱附测试、紫外可见吸收光谱(UV?Vis)及电化学测试对材料进行表征。研究发现:CeTiO 4与g?C 3N 4层状纳米片紧密复合,并成功构建了界面异质结结构;形成CTO/CN?x复合相的光催化材料具有良好的可见光光响应性能,且光生空穴-电子对的分离和迁移率明显提高;通过太阳光模拟不同样品光催化降解有机污染物罗丹明B,降解140 min后复合材料CTO/CN?6表现出最高的光催化活性,反应速率常数为0.0202 min -1。其活性增强的主要原因是异质结结构的构筑降低了CTO光生载流子的复合几率,提高了光生载流子的迁移速率。 相似文献
4.
Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO 3. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O 2•−) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension. 相似文献
5.
C, N codoped TiO 2 catalyst has been synthesized by thermal decomposition of a novel water-soluble titanium complex. The structure, morphology, and optical properties of the synthesized TiO 2 catalyst were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the Pt deposited TiO 2 catalysts synthesized at different temperatures was evaluated by means of hydrogen evolution reaction under both UV–vis and visible light irradiation. The investigation results reveal that the photocatalytic H 2 evolution rate strongly depended on the crystalline grain size as well as specific surface area of the synthesized catalyst. Our studies successfully demonstrate a simple method for the synthesis of visible-light responsive Pt deposited TiO 2 catalyst for solar hydrogen production. 相似文献
6.
ZnTiO 3/tourmaline loaded on the nickel foam (ZnTiO 3/tourmaline/Ni-foam) is prepared by a facile coating method. Morphology and structure of the photocatalyst were characterized by X-ray diffraction (XRD), scanning electrons microscopy (SEM), raman spectroscopy, UV–vis diffuse reflectance spectrum (UV–vis DRS) and photoluminescence spectroscopy (PL). The photocatalytic properties of the materials were tested by using the Rhodamine B (RhB) solution as the target pollutant. The results indicates that the ZnTiO 3/tourmaline/Ni foam exhibited higher photocatalytic activity than that of ZnTiO 3 and ZnTiO 3/Ni foam under ultraviolet (UV) light irradiation, and its degradation rate was up to 99.2%. Moreover, the degradation rate remained at 91.3% after eight consecutive photocatalytic reaction cycles. The outstanding photocatalytic performances of ZnTiO 3/tourmaline/Ni foam was mainly attributed to the existence of tourmaline, which can help to inhibit the recombination of electron-hole paris, and the proper pore structure of the carrier. Meanwhile, the trapping experiments indicated that ·O 2– was the main active species in the photocatalytic degradation of RhB. 相似文献
7.
Melamine was added to the precursor of TiO2, then TiO2 prepared by hydrothermal, while melamine was modified. Subsequently, a series of Z-scheme TiO2/g-C3N4 heterojunction composites were successfully synthesized by simple calcination. The morphology and structure of samples were characterized by XRD, FT-IR, UV–vis DRS, SEM, TEM, PL and BET. The photocatalytic activity of these samples has been investigated by degradation of Rhodamine B (RhB), and results indicated that photocatalytic activity of the as-prepared samples was greatly influenced by the content of titanium tetrabutoxide in precursors and the hydrothermal time. The degradation rate of TiO2/g-C3N4-1 to RhB was the best, which was 5.05-fold of pure TiO2 (19.61%) and 2.25-fold of bulk g-C3N4 (44.06%), respectively. The trapping experiment results showed that ·O2? and h+ were main active species during degradation of RhB. The photocatalytic activity of the sample did not decrease significantly after 4 cycles. The unique Z-scheme heterojunction between TiO2 and g-C3N4 improved photocatalytic activity of the samples under visible light. 相似文献
8.
Cd x Zn 1?x S solid solution photocatalysts were prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), and transmission electron microscope (TEM) measurements. Using glucose as an electron donor, photocatalytic hydrogen generation over Pt/Cd x Zn 1?x S was investigated. The results show that glucose not only improves the efficiency of photocatalytic hydrogen generation but prevents photocorrosion of Cd x Zn 1?x S. Glucose was degraded effectively with the hydrogen generation. The factors which affect photocatalytic hydrogen generation, such as composition and structure of Cd x Zn 1?x S solid solutions, irradiation time, initial concentration of the glucose, and concentration of NaOH were studied. 相似文献
9.
Nowadays, the development of metal-metal sulfide interface semiconductors using green approach is best material for the photocatalytic and biological applications. Here, we provided for the first time, an environmentally friendly route to fabricate bovine serum albumin (BSA) assisted Ag@Bi 2S 3 composites through a metal-metal sulphide interface via a simple hydrothermal method for the evaluation of photochemical and biological applications. The synthesized composites were characterized by UV–vis DRS, PL, XRD, TEM, and N 2 adsorption-desorption isotherms. The UV–vis DRS and PL spectra show that the obtained nano-sized Ag@Bi 2S 3 composite displays enhanced visible-light absorption and a decreased fluorescence emission compared to that of Bi 2S 3 nanorods (NRs). The photocatalytic performances of the synthesized composites were evaluated by the degradation of the single (RhB and MB) and mixed dye (RhB+MB) under sunlight irradiation. The results indicated that the Ag@Bi 2S 3 composite exhibits superior photocatalytic activity (98.38%) than that of individual Ag NPs and Bi 2S 3 NRs due to the synergistic effect of Ag and Bi 2S 3 nanophases in the Ag@Bi 2S 3 composite, which results in an effective charge separation, fast electron transfer from Ag to Bi 2S 3, and a low recombination of photo-induced electron-hole pairs. The Ag@Bi 2S 3 composite also has good recycling stability up to 5 cycles and its mechanism also investigated. The evaluation of reactive species during the photocatalytic reaction was also carried out. Further, the effects of Bi 2S 3 and Ag NPs on the antimicrobial and antioxidant activity of the resultant Ag@Bi 2S 3 composite were also systematically investigated. 相似文献
10.
[Ba 1–xY 2x/3](Zr 0.25Ti 0.75)O 3 powders with different yttrium concentrations ( x = 0, 0.025 and 0.05) were prepared by solid state reaction. These powders were analyzed by X-ray diffraction (XRD), Fourier transform Raman scattering (FT-RS), Fourier transform infrared (FT-IR) and X-ray absorption near-edge (XANES) spectroscopies. The optical properties were investigated by means of ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) measurements. Even with the addition of yttrium, the XRD patterns revealed that all powders crystallize in a perovskite-type cubic structure. FT-RS and FT-IR spectra indicated that the presence of [YO 6] clusters is able to change the interaction forces between the O–Ti–O and O–Zr–O bonds. XANES spectra were used to obtain information on the off-center Ti displacements or distortion effects on the [TiO 6] clusters. The different optical band gap values estimated from UV–vis spectra suggested the existence of intermediary energy levels (shallow or deep holes) within the band gap. The PL measurements carried out with a 350 nm wavelength at room temperature showed that all powders present typical broad band emissions in the blue region. 相似文献
11.
Nanosized cerium and nitrogen co-doped TiO 2 (Ce–TiO 2?xN x) was synthesized by sol gel method and characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), FESEM, Fourier transform infrared, N 2 adsorption and desorption methods, photoluminescence and ultraviolet–visible (UV–vis) DRS techniques. PXRD analysis shows the dopant decreases the crystallite sizes and slows the crystallization of the titania matrix. XPS confirm the existence of cerium ion in +3 or +4 state, and nitrogen in ?3 state in Ce–TiO 2?xN x. The modified surface of TiO 2 provides highly active sites for the dyes at the periphery of the Ce–O–Ti interface and also inhibits Ce particles from sintering. UV–visible DRS studies show that the metal–metal charge transfer (MMCT) of Ti/Ce assembly (Ti 4+/Ce 3+ → Ti 3+/Ce 4+) is responsible for the visible light photocatalytic activity. Photoluminescence was used to determine the effect of cerium ion on the electron–hole pair separation between the two interfaces Ce–TiO 2?xN x and Ce 2O 3. This separation increases with the increase of cerium and nitrogen ion concentrations of doped samples. The degradation kinetics of methylene blue and methyl violet dyes in the presence of sol gel TiO 2, Ce–TiO 2?xN x and commercial Degussa P25 was determined. The higher visible light activity of Ce–TiO 2?xN x was due to the participation of MMCT and interfacial charge transfer mechanism. 相似文献
12.
Three-dimensional (3D) hierarchical porous TiO 2/InVO 4 nanocomposites were fabricated by loading TiO 2 nanoparticles on the surface of porous InVO 4 microspheres. X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence spectroscopy (PL) were adopted to analyze the structure–property relationship of samples. The results show that the surface of as-prepared TiO 2/InVO 4 nanocomposites are composed of uniformly interconnected bi-phase nanocrystals, forming a close interface between these two components, which is favorable for the highly efficient interparticle electron transfer to achieve enhanced photocatalytic properties. However, the adsorption ability is decreased due to the loading of TiO 2 nanoparticles on the surface of InVO 4. Therefore, under the joint action of these factors, the TiO 2/InVO 4 nanocomposites achieve the best photocatalytic activity when the mole ratio of In:Ti reaches 4:1, and the visible-light photocatalytic activity is about as 3.3 times high as that of pure InVO 4 without modification. 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.
Au–TiO 2/bentonite samples were prepared via deposition–precipitation method and calcined at different temperatures. These samples were characterized by X-ray diffraction (XRD), UV–vis diffusion reflectance spectroscopy (DRS), BET method, X-ray photoelectron spectroscopy (XPS) and TEM. The photocatalytic activities of the samples were tested by photodegradation of sulforhodamine B (SRB) under ultraviolet (UV) and visible light irradiation. The result showed that Au–TiO 2/bentonite catalysts exhibited higher efficiency for mineralizing SRB than the well-known commercial TiO 2 photocatalyst P25 in terms of COD changes. The most important advantage of Au–TiO 2/bentonite over P25 was that it could be readily separated from aqueous suspensions by sedimentation after the reaction. It can maintain almost the same activity after being repeatedly used for 12 times. Possible mechanisms for SRB photoreaction in the presence of Au–TiO 2/bentonite were proposed in this paper. 相似文献
15.
TiO 2/g-C 3N 4 nanofibers with diameter of 100–200 nm were prepared by electrospinning method after calcination at high temperature, using polyvinylpyrrolidone (PVP), Melamine (C 3H 6N 6), Ti(OC 4H 9) 4 as raw materials. The composite nanofibers were characterized by XRD, FT-IR, SEM, UV–vis and PL respectively. The effects of different g-C 3N 4 contents on structure and photocatalytic degradation of the composite nanofibers were investigated. The results indicated that with increasing g-C 3N 4 content, the diameter of the composite fibers increased and the morphology changed from uniform structure to a nonuniform one, containing beads. The composite nanofibers displayed the best photocatalytic degradation on RhB, when the g-C 3N 4 content was 0.8 wt%. The degree of degradation was up to 99% at the optimal conditions of 40 min. The degradation activity of the composite nanofibers on RhB, MB and MO was found to be higher than that of the TiO 2 nanofibers. 相似文献
16.
An excellent visible-light-responsive (from 400 to 550 nm) TiO 2−xN x photocatalyst was prepared by a simple wet method. Hydrazine was used as a new nitrogen resource in this paper. Self-made amorphous titanium dioxide precursor powders were dipped into hydrazine hydrate, and calcined at low temperature (110 °C) in the air. The TiO 2−xN x was successfully synthesized, following by spontaneous combustion. The photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), UV-Vis diffuse reflectance spectrometer (DRS), and X-ray photoelectron spectroscopy (XPS). Analysis of XPS indicated that N atoms were incorporated into the lattice of the titania crystal during the combustion of hydrazine on the surface of TiO 2. Ethylene was selected as a target pollutant under visible-light excitation to evaluate the activity of this photocatalyst. The newly prepared TiO 2−xN x photocatalyst with strong photocatalytic activity and high photochemical stability under visible-light irradiation was firstly demonstrated in the experiment. 相似文献
17.
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
18.
Aligned Zn 1-xMg xO nanowire arrays were successfully prepared on Si(111) substrates via the chemical vapor deposition (CVD) method with a mixture of ZnO, Mg, and activated carbon powders as reactants. The microstructures and optical properties of the synthesized Zn 1-xMg xO nanowire arrays were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis X-ray (EDAX), and photoluminescence (PL) spectrum analytic apparatus, respectively. While Mg content was achieved or less approximately 0.29 ( x, atomic ratio) in ZnO lattice, the crystal lattice of the synthesized samples exhibited wurtzite structure. The Mg atoms were distributed into the ZnO crystal as the interstitial and displaced atoms, and there was no phase separation in preparing Zn 1-xMg xO nanowire arrays. However, as the Mg content was up to 0.53 ( x) in the fabricated Zn 1-xMg xO samples, a clear phase separation phenomena appeared in the Zn 1-xMg xO crystal. Compared with the PL spectrum of the pure ZnO nanowire arrays, the analytic results showed that a blue-shift of the near-band edge emission with increasing Mg content was observed in the Zn 1-xMg xO arrays. And the relative intensities of green peak at ca 535 nm and UV emission peak at ca 376 nm were all restrained. 相似文献
19.
AgBr@TiO 2/GO (graphene oxide) ternary composite photocatalyst was synthesized by fabricating core–shell-structured AgBr@TiO 2 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@TiO 2 possessed excellent dispersity. PL analysis revealed that the ternary-structured AgBr@TiO 2/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@TiO 2/GO ternary composite exhibited evidently improved photocatalytic activity compared with AgBr, AgBr@TiO 2, and AgBr/GO. On the basis of the experiment results, the photocatalytic oxidation mechanism of benzyl alcohol over AgBr@TiO 2/GO is tentatively discussed. 相似文献
20.
Nitrogen-doped NaTaO 3 was synthesized through 1-pot reaction, hydrothermal process using Ta 3N 5 as precursor. Changing concentration and amount of NaOH aqueous solution influenced nitrogen content in NaTaO 3. Absorption edge of nitrogen-doped NaTaO 3 was extended at 570 nm, and absorbance in visible light region depended on nitrogen content in NaTaO 3. Anodic photocurrent measured under visible light irradiation became larger with increasing nitrogen content in NaTaO 3-xN y. Under ultraviolet light irradiation ( λ ≤ 400 nm), the highest anodic photocurrent was observed when nitrogen concentration was y = 0.024. It was possible to expand the wavelength range that can be effectively utilized for the photoelectrochemical reaction. 相似文献
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