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Enhanced UV-light driven photocatalytic performances and recycling properties of TiO2/AlON composite photocatalyst
摘要： AlON has been reported to have photocatalytic capability under ultraviolet-light (UV-light), which can be improved by fabricating large-sized powder (~20 μm) having porous skeleton microstructure. To further enhance photocatalytic property of AlON, highly photocatalytic-efficient nanocrystalline TiO2 was loaded onto both the outer and inner surface of porous AlON particles by hydrothermal method. In order to ensure easy recovery without secondary pollution, the obtained composite powder was filtered in deionized water three times to remove both small-sized AlON and free TiO2 particles to produce a composite photocatalyst with particle size > 10 μm. The proposed TiO2/AlON showed excellent photocatalytic performance on Methylene blue (MB) and Methyl orange (MO) for 97.9% and 99.1% of pollutants (in 30 mg/L, 40 mL solution) being degraded by 50 mg as-synthesized composite photocatalyst in 120 min. Further test showed that the hydrothermal process can significantly improve the photocatalytic performance of TiO2/AlON composite photocatalyst and its enhancement mechanism were discussed. In addition, the large-sized composite photocatalyst is easy to recover and stable to reuse with no regeneration needed.
关键词： Hydrothermal method,Composite photocatalyst,TiO2/AlON,UV-light
更新于2025-09-23 15:22:29
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Graphene role in improved solar photocatalytic performance of TiO2-RGO nanocomposite
摘要： TiO2-RGO (TG) nanocomposite applied as photocatalysts have been synthesized via a facile low-temperature wet chemistry process, during which the reduction of graphene oxide (RGO) and the growth of titanium dioxide (TiO2) nanoparticles on the RGO nanosheets are achieved simultaneously. RGO role in TG nanocomposites as photocatalysts were analyzed in methylene blue photocatalytic degradation under UV and solar irradiation. The TG nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The photocatalytic efficiency of the TG-30 sample under UV and TG-45 solar irradiation was ～7 and ～5 times that of pristine TiO2, respectively. The enhancement of the photocatalytic activity with UV irradiation in TG was attributed to the high separation efficiency of photoinduced electron–hole pairs, while the enhancement of photocatalytic activity with solar irradiation in the TG was attributed to RGO role, acted as a photosensitizer and a charges separator, simultaneously.
关键词： semiconductors,Solar photocatalysis,photosensitizer,composite materials,charger separator,recombination and trapping
更新于2025-09-23 15:22:29
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Ag2O/TiO2 nanostructures for the photocatalytic mineralization of the highly recalcitrant pollutant iopromide in pure and tap water
摘要： TiO2 was modified by the deposition of Ag2O nanoparticles to increase the photocatalytic degradation of iopromide in water under UV–C (λ = 254 nm) and UV–A/visible light irradiation (380–800 nm) using pure and tap water. Several loadings of Ag2O were deposited on TiO2, namely 0.03, 0.15, 0.25, 0.65, 1.0, 1.15, 1.35 and 1.8 wt. %. XRD, TEM, BET, ICP-OES, XPS, DRS and cathodoluminescence spectroscopy were carried out to characterize the materials, while semiconducting properties of the composite were elucidated through electrochemical and photoelectrochemical characterization. Under UV–C light irradiation, the Ag2O/TiO2 heterostructures showed higher mineralization of iopromide (up to 86%, using the 1.15 wt. % Ag2O/TiO2 material) than unmodified materials (37% for TiO2 and 14% for Ag2O), indicating a synergistic effect by the combination of both compounds in the composite. Under UV–A/visible light irradiation, mineralization achieved with the 1.15 wt. % Ag2O/TiO2 material decreased up to 65%, which was again higher than that obtained for its single components. Stability of the photocatalyst was observed through three consecutive reaction cycles under UV–A/visible light irradiation. In tap water, environmentally relevant concentrations of iopromide were tested (Co = 50 μg L?1), resulting in a high degradation rate, while mineralization dramatically decreased because of the matrix effect. Some by-products were identified by mass spectroscopy and a possible degradation path was proposed. The outstanding photocatalytic activity of the Ag2O/TiO2 materials was explained by the electron trap effect exerted by Ag2O, along with the appearance of different silver species (Ag2O, Ag2O2 and Ag°) throughout the photocatalytic reaction, enhancing the mobility of the charge carriers and thus the generation of reactive species on the photocatalyst surface.
关键词： Semiconductors,X-ray contrast media,Tap water,Photocatalysis,Composite
更新于2025-09-23 15:22:29
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Enhanced optical properties of YAG:Ce yellow phosphor by modification with gold nanoparticles
摘要： In this paper methods of synthesis and characterization of cerium doped yttrium aluminum garnet (YAG:Ce) and the improvement of properties by in situ modification using gold nanoparticles are presented. YAG:Ce phosphor was obtained by cations co-precipitation followed by thermal treatment at 1000 °C, while for the development of the Au-YAG:Ce nanocomposites, the Turkevich method was used. The quality of the phosphor particles and composite has been structurally, morphologically and optically studied. It has been emphasized the obtaining of high purity phosphor and maintenance of the YAG:Ce garnet structure after modifying the phosphor surface with gold nanoparticles. Also, the use of gold nanoparticles has led to improvements in optical and morphological properties as a result of lowering the agglomeration trend. Improvement of optical properties makes possible the use of Au-YAG:Ce composite thus developing low energy light sources and with high performance.
关键词： YAG:Ce,Au-YAG:Ce composite,Optical materials,Phosphor
更新于2025-09-23 15:22:29
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Enhanced dielectric permittivity in surface-modified graphene/PVDF composites prepared by an electrospinning-hot pressing method
摘要： In the present work, the surface-modified graphene (SMG)/poly(vinylidene fluoride) (PVDF) fibrous membranes obtained from the electrospinning were treated by the hot pressing in the laminating mode to form the SMG/PVDF composites. The SMG was prepared by subjecting the graphene oxide to silane modification, NaBH4 reduction, and PVDF grafting in sequence. The successful surface modification of graphene was confirmed by TEM, XPS, Raman spectroscopy, FTIR, WAXD, and TGA. Furthermore, the structures of SMG/PVDF composites fabricated by the electrospinning-hot pressing method were studied by SEM, FTIR, and WAXD, which exhibited the well dispersion of SMG in the PVDF matrix. Finally, the investigation showed that the dielectric permittivities of SMG/PVDF composites increased with the SMG content, which were significantly higher than that of pristine PVDF. The dielectric permittivity of SMG (16 wt.%)/PVDF composite (83.8) at 1000 Hz was found to be ten-fold that of the corresponding value of pristine PVDF (8.3) with a relatively low dielectric loss factor (0.34) and a relatively high thermal conductivity (0.679 W/mK).
关键词： surface-modified graphene/PVDF composite,thermal conductivity.,electrospinning-hot pressing method,dielectric performance
更新于2025-09-23 15:22:29
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Impact Localization System for Composite Barrel Structure using Fiber Bragg Grating Sensors
摘要： Composite barrel structures are widely used in manufacturing of aircrafts and spacecrafts, the localization of impact on composite barrel structures are essential for structure health monitoring and safety assurance. In this paper, an LVI localization system was established on a composite barrel structure with fiber Bragg grating sensors, by analyzing the relationship between the wavelet packet energy spectrum of LVI response signals monitored by FBG sensors and corresponding impact locations on composite barrel structure, the zeroth node’s energy was found to be sensitive to LVI location, and an impact localization method for composite barrel structure which use the zeroth node’s energies as LVI feature values to predict the LVI locations by means of support vector regression (SVR) was proposed. The performance of the zeroth node’s energy based localization method were compared with localization methods that based on the energy of the fourth node which covers the natural frequency of the composite barrel structure or the total energy of frequency domain. The proposed localization method based on the zeroth node’s energy and SVR demonstrates an effective and practical means for localization of LVI on composite barrel structure with low sampling rate fiber bragg grating sensors and small computation.
关键词： Composite barrel structure,Wavelet analysis,Fiber Bragg gratings.,Impact localization
更新于2025-09-23 15:22:29
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Photocatalytic and Filtration performance study of TiO2/CNTs-Filter for oil particle
摘要： Carbon nanotubes (CNTs) with large aspect ratio and specific surface area have the potential in oil liquid particle filtration and catalysis substrate field. In this work, we synthesized the TiO2/CNTs-filter for removing oil particle. Compared with the CNTs-filter, we found that the TiO2/CNTs-filter has smaller pore sizes, higher specific area. TiO2/CNTs-filter shows the excellent filtration performance which is higher than the high efficiency particulate air (HEPA) filter. In addition, the initial pressure drop of TiO2/CNTs-filter is close to conventional HEPA filter and the raise ratio of pressures drop at equilibrium states is less than conventional HEPA filter. Furthermore, the degradation rate of initial state and saturation state reach to 94.5 and 724 μg cm-2 h-1 in first 20 h respectively. At last, we simply discuss the application the composite filter on filtering cooking fume.
关键词： carbon nanotubes,filtration,composite filter,oil particle,photocatalytic
更新于2025-09-23 15:22:29
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Investigations on Synthesis, Characterization and Humidity Sensing Properties of ZnO and ZnO-ZrO2 Composite Nanoparticles Prepared by Ultrasonic Assisted Wet Chemical Method
摘要： In the present investigations, Zinc oxide (ZnO) and ZnO-ZrO2 composite nanoparticles were synthesized by ultrasonic assisted wet chemical method to investigate their structural, optical and humidity sensing properties. The synthesized nanoparticles were characterized by the techniques like X ray diffraction (XRD), UV-Vis absorption spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). XRD and EDS were employed to confirm the phase formation and phase purity respectively. SEM micrographs showed that morphology of the parent compound ZnO is considerably changed with varying concentration of ZrO2. The optical absorption spectra showed that optical absorption of ZnO decreases with increase in ZrO2 content in the composite. The observed band gap values for ZnO and ZnO-ZrO2 composites were higher as compared to the bulk sample. The humidity sensing performance was substantiated for all the samples and the result of effect of concentration of ZrO2 in ZnO-ZrO2 composites on sensitivity, response and recovery time are discussed in detail.
关键词： Zinc oxide,Composite nanoparticles,Zirconium dioxide,Ultrasonic,Humidity sensor
更新于2025-09-23 15:22:29
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A Novel Design of Through-Hole Depth On-Machine Optical Measuring Equipment for Automatic Drilling and Riveting
摘要： In the aerospace manufacturing industry, it is impossible to achieve precise and efficient automatic drilling and riveting for largescale composite board parts. The bottleneck is that the depth detection of rivet holes still relies on manual operation, which seriously affects the assembly efficiency and stability of composite board parts. In order to realize accurate and efficient on-machine automatic measurement for through holes in the automatic drilling and riveting process of largescale composite board parts, this paper presents a novel hole depth measuring device. Its mechanical structure is developed based on our newly designed measurement scheme and optical path, the purpose of which is to convert the hole depth data into displacement data of the probe motion. Its electrical hardware consists of three units: a laser transceiver unit to pick up laser spots; a displacement measuring unit to capture the probe movement in real time; and a driving unit to achieve motion control of the probe. Finally, the experimental results indicated that the proposed method and device are capable of performing automatic measurements for through-hole depth. In addition, factors affecting the measuring accuracy and stability of the device are initially analyzed and discussed, which lay a foundation for subsequent research on error compensation and probe calibration.
关键词： image processing,depth detection,automatic drilling and riveting,through-hole depth,large-scale composite board,on-machine measurement
更新于2025-09-23 15:22:29
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Photocatalytic Activity of Monosized AuZnO Composite Nanoparticles
摘要： Photocatalytic activity of monosized AuZnO composite nanoparticles with different compositions were synthesized by the one-pot polyol procedure, using the triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-blockpoly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The structure and morphology of the composite nanoparticles were analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), selected area electron diffraction (SAED), a transmission electron microscope (TEM) and high resolution transmission electron microscopy (HRTEM). The characterization showed that the AuZnO composite nanoparticles were spherical, with narrow particle size distribution and high crystallinity. The Fourier transform infrared spectroscopy (FTIR) study con?rms the PEO-PPO-PEO molecules on the surface of the composite nanoparticles. The investigations by ultraviolet-visible light absorbance spectrometer (UV-Vis) and photoluminescence spectrophotometer (PL) demonstrate well the dispersibility and excellent optical performance of the AuZnO composite nanoparticles. Photocatalytic activity and reusability of the AuZnO nanoparticles in UV and visible light regions was evaluated by the photocatalytic degradation of Rhodamine B (RhB). The experimental results show that the AuZnO composite nanoparticles with a suitable amount of Au loading have stability and improved photocatalytic activity. AuZnO composite nanoparticles are effective and stable for the degradation of organic pollutants in aqueous solution.
关键词： one-pot polyol synthesis,photocatalytic activity,AuZnO composite nanoparticles,optical performance
更新于2025-09-23 15:22:29