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291.
Novel magnetic hybrid nanomaterials 1 (LaFeO3.Fe3O4@SiO2-NH2/PW12) were synthesized by supporting phosphotungstic acid (H3PW12O40; PW12) on LaFeO3.Fe3O4 nanomaterials through sono-assisted method. The synthesized nanomaterials were fully characterized by using FT-IR, XRD, UV–vis, BET-BJH, VSM, SEM, and TEM analyses. FT-IR, XRD, and UV–vis confirmed successful synthesis of nanomaterials. The SEM and TEM images revealed spherical morphology with core-shell structure for hybrid nanomaterials 1 . VSM results confirmed the magnetic property of hybrid nanomaterials 1 and suggested it as easily recyclable photocatalyst for removal of organic dyes from aqueous solution. The photocatalytic activity of hybrid nanomaterials 1 has been studied over the degradation of methylene blue (MB) and methyl orange (MO) solution under UV–vis light irradiation. Importantly the hybrid nanomaterials 1 showed outstanding degradation efficiency for MB solution in comparison with bare LaFeO3.Fe3O4 and PW12. The photocatalytic activity was enhanced mainly due to the high efficiency in separation of electron–hole pairs induced by the remarkable synergistic effects of LaFeO3.Fe3O4 and PW12 semiconductors. After the photocatalytic reaction, the nanocomposite can be easily separated from the reaction solution and reused several times without loss of its photocatalytic activity. Trapping experiments indicated that hole (hVB+) and •OH radicals were the main reactive species for dye degradation in the present photocatalytic system. On the basis of the experimental results and estimated band gaps, the mechanism for the enhanced photocatalytic activity was proposed. 相似文献
292.
In this paper Cu3V2O8 nanoparicles were synthesized with a low-cost and green method with using the extract of Moringa peregrine. This novel synthesized material was characterized by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Energy-dispersive X-ray spectroscopy (EDS) analysis. The analysis showed the produced nanoparticles have high purity and well crystalline structure. Moreover, the capability of the nanostructures for the removal of dye pollutants was evaluated. For this purpose, methylene blue was selected as a model of organic dye. The experiments showed Cu3V2O8 nanoparticles have high efficiency for removing of dye molecules. Photocatalytic decolorization of methyl blue was optimized with varying the experiment conditions. With 0.02 g of catalyst, pH 6 and concentration of dye 30 mg/l removal efficiency was obtained about 90% in a short time 20 min. Also a kinetic study showed this photodegradation process obeys a first-order kinetic with rate constant about 0.07 min−1. 相似文献
293.
Emmanuel Kweinor Tetteh Elorm Obotey Ezugbe Dennis Asante-Sackey Edward Kwaku Armah Sudesh Rathilal 《Molecules (Basel, Switzerland)》2021,26(4)
Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2–4 g), reaction time (15–45 min) and pH (6–9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%. 相似文献
294.
Nanoscale anatase TiO2 single crystals were successfully synthesized using three kinds of activated carbon (AC) templates through a simple sol–gel method. The optimal photocatalyst (T‐WOAC) was obtained using wood‐based AC template. X‐ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller analyses revealed that T‐WOAC possessed a small crystallite size of 8.7 nm and a clear mesoporous structure. The photocatalytic properties of samples were then evaluated through photodegradation of crystal violet (CV). Results implied that the photocatalysts prepared using the AC templates exhibited superior photocatalytic activity to that of the original TiO2. This enhancement may be due to the small crystallite size, large specific surface area and pore volume of the catalysts prepared with ACs. T‐WOAC showed high photocatalytic activity, CV degradation of 99.01% after 120 min of irradiation and k = 0.03914 min?1, which is 3.9 times higher than that of the original TiO2 (k = 0.00994 min?1). This result can be mainly attributed to the application of WOAC with moderate specific surface area and pore volume to produce T‐WOAC. Alkaline conditions benefitted the photodegradation of CV over photocatalysts. This work proposes a possible degradation mechanism of CV and indicates that the fabricated photocatalysts can be used to effectively remove CV from aqueous solutions. 相似文献
295.
Erjun Lu Zhixiang Zhang Junqian Tao Prof. Zhiyang Yu Prof. Yidong Hou Prof. Jinshui Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(56):e202201590
The selective immobilization of noble metals right at the place where photogenerated electrons migrate through the photodeposition approach is a unique strategy to load cocatalysts on semiconductors for solar hydrogen production. However, a poor metal–semiconductor interaction is often formed, which not only hinders the interfacial charge transfer, but also results in the easy aggregation and shedding of cocatalysts during photocatalytic reactions. Herein, it is demonstrated that the photodeposited ultrafine metals, such as nanosized Au, can be well stabilized on TiO2 nanocrystallines without sintering by employing a sacrificial carbon coating annealing strategy to strengthen the metal-support interaction. Benefiting from the improved interfacial contact between Au and TiO2 for fast charge transfer and the well-preserved size-dependent catalytic behavior of Au nanoparticles toward hydrogen evolution reaction, the annealed Au/TiO2 exhibits a significant enhanced activity toward photocatalytic H2 production with good durability. 相似文献
296.
Visible‐light‐driven plasmonic photocatalyst Ag‐TiO2 nanocomposite hollow spheres are prepared by a template‐free chemically‐induced self‐transformation strategy under microwave‐hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, N2 adsorption‐desorption isotherms, X‐ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of ?OH radicals on the surface of visible‐light illuminated TiO2 was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as‐prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible‐light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO2 hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag‐TiO2 nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible‐light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO2 and commercial Degussa P25 (P25) powders. Especially, the as‐prepared Ag‐TiO2 nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium ( R ) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2. 相似文献
297.
Eu/FeVO_4新型光催化剂的制备及其光催化性能 总被引:2,自引:0,他引:2
以偏钒酸铵(NH4VO3)、硝酸铁(Fe(NO3)3.9H2O)、硝酸铕(Eu(NO3)3)为原料,采用浸渍法制备了Eu/FeVO4新型光催化剂,并利用XRD,SEM,BET,DRS和XPS等手段对其进行了表征。结果表明:Eu/FeVO4仍为三斜型晶体,其晶粒粒径大小未有显著变化;SEM显示掺杂后晶体表面附着较多细小颗粒,其比表面积得到了提高;并且其光吸收性能在200~500 nm之间增强。在12 W节能灯照射下,以甲基橙的光催化剂降解为模型反应,研究了该新型光催化剂的光催化活性。结果发现,与纯FeVO4样品相比,Eu/FeVO4样品光催化活性大幅提高,且当掺杂量为0.5%(质量分数)时,对甲基橙溶液的脱色率比纯FeVO4提高24%左右。 相似文献
298.
299.
The crystal structures, electronic structures and optical properties of nitrogen or/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density functional theory. Highly efficient visible-light-induced nitrogen or/and praseodymium doped anatase TiO2 nanocrystal photocatalyst were synthesized by a microwave chemical method. The calculated results show that the photocatalytic activity of TiO2 can be enhanced by N doping or Pr doping, and can be further enhanced by N+Pr codoping. The band gap change of the codoping TiO2 is more obvious than that of the single ion doping, which results in the red shift of the optical absorption edges. The results are of great significance for the understanding and further development of visible-light response high activity modified TiO2 photocatalyst. The photocatalytic activity of the samples for methyl blue degradation was investigated under the irradiation of fluorescent light. The experimental results show that the codoping TiO2 photocatalytic activity is obviously higher than that of the single ion doping. The experimental results accord with the calculated results. 相似文献
300.
Structure and electronic structure of S-doped graphitic C3N4 investigated by density functional theory
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The structures of the heptazine-based graphitic C3N4 and the S-doped graphitic C3N4 are investigated by using the density functional theory with a semi-empirical dispersion correction for the weak long-range interaction between layers.The corrugated structure is found to be energetically favorable for both the pure and the S-doped graphitic C3N4.The S doptant is prone to substitute the N atom bonded with only two nearest C atoms.The band structure calculation reveals that this kind of S doping causes a favorable red shift of the light absorption threshold and can improve the electroconductibility and the photocatalytic activity of the graphitic C3N4. 相似文献