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Synthesis of Al-MCM-41@Ag/TiO <sub/>2</sub> Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene
摘要： Mesoporous Al-MCM-41@Ag/TiO2 nanocomposites were synthesized successfully by combining the sol-gel method and hydrothermal treatment, using titanium isopropoxide (TTIP), AgNO3, and Vietnamese bentonite as precursors of Ti, Ag, and Si, respectively. The synthesized materials were well characterized by X-ray powder di?raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherm measurements, energy dispersive X-ray spectroscopy (EDX), UV-visible di?use re?ectance spectroscopy (UV-Vis/DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the photodegradation of dibenzothiophene (DBT) under both UV and visible light irradiation. MCM-41@Ag/TiO2 catalyst exhibited high catalytic activity for the oxidative desulfurization (ODS) of DBT reaching almost 100% conversions at 50°C after 2 h under UV and visible light irradiations. The signi?cant enhanced degradation of DBT over Al-MCM-41@Ag/TiO2 might be due to the synergy e?ects of high surface area of MCM-41, well-distributed TiO2 anatase, and reduced electron-hole recombination rates due to the dispersion of Ag nanoparticles.
关键词： photocatalytic activity,Al-MCM-41@Ag/TiO2,dibenzothiophene,visible light irradiation,oxidative desulfurization
更新于2025-09-04 15:30:14
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mpg-C <sub/>3</sub> N <sub/>4</sub> /Ag <sub/>2</sub> O Nanocomposites Photocatalysts with Enhanced Visible-Light Photocatalytic Performance
摘要： To study the photocatalytic activity under visible light irradiation, a series of mesoporous graphitic carbon nitride (mpg-C3N4)/Ag2O photocatalysts were synthesized. The as-prepared photocatalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption Brunauer-Emmett-Teller method (N2-BET), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (DRS), and photoluminescence spectra (PL) methods to determine their phase structure, purity, morphology, spectroscopic and photoluminescence emission performance, respectively. Photocatalytic degradation of methyl orange (MO) aqueous solution under visible-light irradiation indicated that the mpg-C3N4/Ag2O-50 nanocomposite exhibited the best activity. The degradation rate of MO reached to 90.8% in 120 min onto the mpg-C3N4/Ag2O-50 nanocomposite, and as compared with the pure mpg-C3N4 and Ag2O samples, the photocatalytic activity of the mpg-C3N4/Ag2O-50 nanocomposite was greatly enhanced. The enhancement of photocatalytic activity was mainly ascribed to the enhanced visible-light absorption ability and the formation of p–n heterojunctions between counterparts of the nanocomposites, which promoted the generation and separation of charge carriers.
关键词： mpg-C3N4/Ag2O,MO Degradation,Photocatalytic Activity,Visible-Light Photocatalysis,p–n Heterojunctions
更新于2025-09-04 15:30:14
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Facile Preparation and Photocatalytic Properties of TiO <sub/>2</sub> Fiber Membrane with Wrinkle Structure
摘要： Herein, TiO2 fiber membrane with wrinkle structure was fabricated by an electrospinning technique in combination with a sol–gel process. The as-prepared TiO2 membranes were interwoven with interconnected nanofibers. The surfacial and morphological features of the obtained TiO2 fiber membrane could be tuned by varying the content of the precursor, titanium (IV) n-butoxide. The nature of wrinkle structure and high surface area demonstrates an impact on the electron–hole separation and charge transfer during photocatalytic tests, thereby leading to an obvious enhancement in the photocatalytic performance. The results revealed the resultant TPNs-20 sample displayed the best photocatalytic performance toward the removal of methyl orange (MO), and its degradation degree was up to 97% within 70 min. Furthermore, a photocatalytic mechanism is proposed on the basis of results and analysis, which indicates that ?OH and ?O?2 radicals are the main reactive species responsbile for the enhanced photocatalytic activity. We anticipate that controllable synthesis of promising TiO2 fiber membranes in this study provides new insight into the development of efficient photocatalysts for high-performance environmental remediation.
关键词： Photocatalytic Activity,Wrinkle Structure,TiO2 Fiber Membrane,Electrospinning
更新于2025-09-04 15:30:14
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Cr(III)-Doped ZnO Nanoflowers: Synthesis, Mechanism and Enhanced Photocatalytic Activity
摘要： ZnO is one of the most widely used photocatalyst, however, because of the wide band gap, its utilization for visible light is unsatisfactory. Therefore, current efforts are directed toward reducing the band gap of ZnO. Transition metal doping has emerged as a promising method, being capable of not only effectively reducing the band gap of ZnO, but inhibiting the recombination of electron–hole pairs. Cr(III)-doped ZnO nano?owers with different Cr/Zn molar ratios were synthesized by a mild, facile and eco-friendly solvothermal process. Subsequently, through various characterizations, it was con?rmed that the dopant Cr(III) entered the lattices of ZnO, substituting the Zn. Owing to the synergy of ?ower-like morphology and Cr(III) dopant, the photocatalytic activity of the products was signi?cantly improved. The optimal Cr/Zn molar ratio was 4%, and the photocatalytic activity of 4% Cr(III)-doped ZnO nano?owers was 1.3 and 3.4 times higher than that of pure ZnO under UV and visible light irradiation, respectively. In addition, the photocatalytic degradation kinetics of methyl orange were also discussed. Furthermore, the mechanism for the improvement in photocatalytic performance of Cr(III)-doped ZnO nano?owers was also investigated based on a series of characterization results such as the UV-vis diffuse re?ectance spectra, photoluminescence, photocurrent and the ?rst-principles calculation.
关键词： Photocatalytic Activity,Mechanism,Nano?owers,Cr-Doped ZnO
更新于2025-09-04 15:30:14
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Preparation and Photocatalytic Activities of Black TiO <sub/>2</sub> in Vacuum and Ambient Temperature Environment
摘要： The preparation conditions are important for the structure and properties of black TiO2. In this paper, the black rutile TiO2 with a particle size of approximately 5 nm was prepared in vacuum by the infrared nano-second laser sputtering deposition method. The study results indicated that the prepared black TiO2 exhibited high light absorption from UV to near-infrared region. The lattice distortion and Ti3+ were responsible for the upward shift in the valance band, and the oxygen vacancy states were determined to be located about 0.7–1.18 eV under the conduction band, narrowing the band gap of TiO2 from 3.2 eV to 2.1 eV. Although the black TiO2 exhibited strong adsorption effects within the full spectrum and had a higher free carrier density, the presence of excess oxygen defects resulted in a higher recombination rate of the photo electron–hole pairs, which induced a poor photocatalytic performance of the black TiO2. This work facilitates the understanding of the mechanisms mechanism of black TiO2 formation via laser ablation, and emphasized the need for the controllability and quanti?cation of oxygen vacancies.
关键词： Vacuum,Laser Ablation,Oxygen Vacancy,Photocatalytic Activity,Black TiO2
更新于2025-09-04 15:30:14
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Green synthesis, characterization and antifungal and photocatalytic activity of Pithecellobium dulce peel–mediated ZnO nanoparticles
摘要： Zinc oxide (ZnO) nanoparticles (NPs) were synthesized by a conventional method using Pithecellobium dulce peel extract. The phytochemicals present in the peel act as stabilizing agents. The ZnO NPs were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy. The XRD pattern confirmed the formation of crystals, which exactly matched with JCPDS card no.36-1451. The nondestructive XRD pattern showed a hexagonal crystalline nature, and scanning electron microscopy revealed a spherical shape. Further, the ZnO NPs exhibited excellent photodegradation efficiency with regard to the dye methyleneblue (MB), a major water pollutant released by the textile industry. A kinetic study of photodegradation of MB showed 63% degradation and a rate constant of 0.00812 min-1. The antifungal activity of the ZnO NPs resulted in 37.81% and 63.57% inhibition of the growth of Aspergillus flavus and 40.21% and 43.04% of growth inhibition of Aspergillus niger at 500 and 1000ppm of ZnO NPs, respectively.
关键词： Photocatalytic activity,Methylene blue,Antifungal,Pithecellobium dulce,ZnO nanoparticles
更新于2025-09-04 15:30:14
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Photocatalytic Performance on Visible Light Induced ZnS QDs-MgAl Layered Double Hydroxides Hybrids for Methylene Blue Dye Degradation
摘要： Semiconductor hybrids based photocatalytic reaction is one of the prominent methods to treat wastewater, containing the organic pollutants. In the present work, we report the development of ZnS QDs-LDH hybrid structure for the photocatalytic treatment of methylene blue (MB) dye. The as-synthesized ZnS QDs-LDH hybrid structure was characterized by XRD, FESEM, HRTEM, EDX, XPS, and FTIR to analyze the formation, morphology and chemical structure. The UV-Vis DRS was used to investigate the optical absorption characteristics of the ZnS QDs-LDH hybrid. The photocatalytic performance of the as-prepared samples was investigated against the methylene blue dye molecule under UV-Vis light irradiation. The scavenging experiments were carried out in order to probe the radical formation by using EDTA, benzoquinone, and 2-proponal. The cycling experiments were performed to check the stability of the ZnS QDs-LDH hybrid photocatalyst after repeated photodegradation experiments.
关键词： ZnS Quantum dots,Layered double hydroxides,Photocatalytic activity,Methylene blue dye degradation,Water treatment
更新于2025-09-04 15:30:14
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Synthesis of Lead-Doped SrTiO <sub/>3</sub> Perovskite Type Oxides and Their Photocatalytic Activity Under Visible Light Irradiation
摘要： Pure and lead-doped SrTiO3 perovskite type oxides were successfully synthesized by sol–gel method and characterized by XRD, SEM and DRS. From the results of XRD, the metal replacement with the Pb ion on the crystal lattice does not change the high crystallinity of the perovskite structure. UV-vis DRS analysis shows that Pb was in situ doped in the lattice of SrTiO3 and the absorption band shifted to a higher wavelength on the Pb-doped SrTiO3 sample compared to the pure SrTiO3 sample. We also investigated the photocatalytic activity of Pb-doped SrTiO3 for the decomposition of Rhodamine B under visible light irradiation. From the results of photocatalytic decomposition of RhB, a doping of lead into SrTiO3 perovskite oxides enhanced the photocatalytic activity under visible light irradiation.
关键词： Photocatalytic Activity,Visible Light Irradiation,Lead-Doped SrTiO3
更新于2025-09-04 15:30:14
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Antioxidant and Photocatalytic Activity of Aqueous Leaf Extract Mediated Green Synthesis of Silver Nanoparticles Using <i>Passiflora edulis f. flavicarpa</i>
摘要： The purpose of this study is to minimize the negative impacts of synthetic procedures and to develop environmentally benign procedures for the synthesis of metallic nanoparticles. In the present study, Passiflora edulis f. flavicarpa (P. edulis) aqueous leaf extract mediated green synthesis of silver nanoparticles are described. The synthesized silver nanoparticles were characterized by UV-Vis Spectroscopy, Fluorescence Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) Transmission Electron Microscopy (TEM) and Cyclic Voltammetry (CV). The silver nanoparticles (AgNPs) showed antibacterial activities against both gram positive (staphylococcus) and gram negative (Escherichia coli) bacteria. The efficacy of the synthesized silver nanoparticles (AgNPs) was demonstrated as catalyst in the photocatalytic degradation of Methyl Orange (MO) and Methylene Blue (MB) dyes which were measured spectrophotometrically. The study revealed that biosynthesized silver nanoparticles using Passiflora. edulis f. flavicarpa, plant extract was found to be very effective as antioxidant agent.
关键词： Photocatalytic Activity,Green Synthesis,Silver Nanoparticles,Passiflora edulis f. flavicarpa,Antioxidant
更新于2025-09-04 15:30:14
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Alkaline Hydrothermal Synthesis, Characterization, and Photocatalytic Activity of TiO <sub/>2</sub> Nanostructures: The Effect of Initial TiO <sub/>2</sub> Phase
摘要： One-dimensional (1D) titanate nanostructures were synthesized by hydrothermal route, using commercially available TiO2 (P25) and anatase powders as precursor materials and strong NaOH solution as catalyzer. The prepared titanates were calcined, followed by protonation to produce TiO2 nanostructures having enhanced photocatalytic and photovoltaic properties. The synthesized TiO2 1D nanostructures were characterized using field-emission scanning electron microscope, high-resolution electron microscope, X-ray diffraction analysis, and UV-Vis photospectroscopy to understand the effect of initial TiO2 phase on morphological and crystallographic features, and bandgap. Methylene blue degradation test was applied to evaluate the photoactivity of the products obtained after different stages of the process. The findings indicate that 1D TiO2 nanostructures form by different mechanisms from dissolved aggregates during hydrothermal process, depending on the crystal structure of the initial precursor used. Photocatalytic test results reveal that protonated titanates have considerable adsorption capability, while photocatalytic degradation depends on TiO2 transformation.
关键词： TiO2,Photocatalytic Activity,1D Structure,Hydrothermal Process,Nanoribbons
更新于2025-09-04 15:30:14