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Recoverable magnetic CoFe2O4/BiOI nanofibers for efficient visible light photocatalysis
摘要： A facile methodology for fabricating novel magnetic fibrous visible light photocatalysts CoFe2O4/BiOI (CFO/BiOI) is presented. The fabrication procedure involves production of electrospun CoFe2O4 nanofibers and subsequent controllable decoration of BiOI nanoplates by both the successive ionic layer adsorption and reaction (SILAR) and solvothermal methods on CoFe2O4 nanofiber surface. The BiOI nanoplates on the fiber surface obtained by two methods are highly crystallized with lamellae morphology. The resulting CFO/BiOI fibers exhibit strongly magnetic response to external magnetic field and can be quickly collected. All the CFO/BiOI fiber samples exhibit excellent visible light photocatalytic performance towards degrading RhB regardless of the preparation methods, in which h+ and ?O2? play the major roles examined by the trapping experiment. Above 80% RhB dyes can be degraded within 2 h after 3 cycles under visible light irradiation, suggesting the good reusability of the photocatalysts. This work demonstrates that the CFO/BiOI is characteristic with high visible light photocatalysis performance and magnetic response, hence is promising for photocatalysis.
关键词： photocatalysis,Electrospinning,BiOI nanoplates,CoFe2O4 nanofibers
更新于2025-09-09 09:28:46
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Optimizing electrospinning-hydrothermal hybrid process based on Taguchi method for modulation of point defects in ZnO micro/nano arrays towards photoelectronic application
摘要： Unlike previous work generally adopting high temperature annealing (≥500 ℃) to suppress defects in hydrothermal grown ZnO, this work suppressed ZnO defects by optimizing overall process parameters of low temperature electrospinning-hydrothermal hybrid process (≤300 ℃) with Taguchi method and Analysis of Variance (ANOVA). Sum ratio of defect peaks to eigen peaks (SRDE) in room-temperature photoluminescence (PL) spectrum was proposed to evaluate defect conditions in 27 experiments (L27 (38)). With the optimal process, good crystal quality (SRDE=0.31) was achieved at low temperature (200 ℃), of which the SRDE decreased by 68.04% compared with the initial counterpart. Then confirmation experiment was conducted to validate the selected levels, and results of signal-to-noise ratio (SNR) showed good agreement with the predicted ones. Besides, the response time and recovery time of the ZnO photodetectors with optimal process were decreased by 72.5% and 79.3%, respectively, compared with the initial ones. This method can also be used to fabricate ZnO materials with other wanted defect features.
关键词： Point defect,photodetector,ZnO micro/nano array,electrospinning-hydrothermal hybrid process,Taguchi method
更新于2025-09-09 09:28:46
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Core-Shell Electrospun Polycrystalline ZnO Nanofibres for Ultra-Sensitive NO2 Gas Sensing
摘要： This paper discusses the growth of polycrystalline, self-supporting ZnO nanofibres which can detect nitrogen dioxide (NO2) gas down to 1 part per billion (ppb), one of the smallest detection limits reported for NO2 using ZnO. A new and innovative method has been developed for growing polycrystalline ZnO nanofibres. These nanofibres have been created using core-shell electrospinning of inorganic metal precursor zinc neodecanoate, where growth occurs at the core of the nanofibres. This process produces contamination-free, self-supporting, polycrystalline ZnO nanofibres of the average diameter and grain size 50 nm and 8 nm respectively, which are ideal for gas sensing applications. This process opens up an exciting opportunity for creating nanofibres from a variety of metal oxides, facilitating many new applications especially in the areas of sensors and wearable technologies.
关键词： NO2 gas sensing,polycrystalline fibres,ZnO nanofibres,Electrospinning
更新于2025-09-09 09:28:46
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Electrical Conductivity Modulation of Crosslinked Composite Nanofibers Based on PEO and PEDOT:PSS
摘要： The aim of this work is to investigate the development of nano?ber mats, based on intrinsically conductive polymers (ICPs), which show simultaneously a high electrical conductivity and mandatory insoluble water properties. In particular, the nano?bers, thanks to their properties such as high surface area, porosity, and their ability to o?er a preferential pathway for electron ?ow, play a crucial role to improve the essential characteristics ensured by ICPs. The nano?ber mats are obtained by electrospinning process, starting from a polymeric solution made of polyethylene oxide (PEO) and poly(styrene sulfonate) (PEDOT:PSS). PEO is selected not only as a dopant to increase the electrical/ionic conductivity, as deeply reported in the literature, but also to ensure the proper stability of the polymeric jet, to collect a dried nano?ber mat. Moreover, in the present work, two di?erent treatments are proposed in order to induce crosslinking between PEO chains and PEDOT:PSS, made insoluble into water which is the ?nal sample. The ?rst process is based on a heating treatment, conducted at 130°C under nitrogen atmosphere for 6 h, named the annealing treatment. The second treatment is provided by UV irradiation that is e?ective to induce a ?nal crosslinking, when a photoinitiator, such as benzophenone, is added. Furthermore, we demonstrate that both crosslinking treatments can be used to verify the preservation of nanostructures and their good electrical conductivity after water treatment (i.e., water resistance). In particular, we con?rm that the crosslinking method with UV irradiation results to being more e?ective than the standard annealing treatment. Indeed, we demonstrate that the processing time, required to obtain the ?nal crosslinked nano?ber mats with a high electrical conductance, results to being smaller than the one needed during the heating treatment.
关键词： PEO,PEDOT:PSS,intrinsically conductive polymers,electrical conductivity,nano?ber mats,water resistance,electrospinning,crosslinking
更新于2025-09-09 09:28:46
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Photostability of oxygen-sensitive core-shell nanofibers
摘要： Core-shell electrospun nanofibers constitute a vehicle enabling novel uses for phosphorescent oxygen-sensitive molecules. In this work, we investigate compositional parameters and other factors governing fiber design appropriate to long-term sensor applications. These nanofibers contain an oxygen-sensitive palladium (II) porphyrin species within a polysulfone core; an outer polycaprolactone shell protects the core from the surrounding environment. The presence of a core-shell architecture was confirmed using advanced time-of-flight secondary ion mass spectrometry (ToF-SIMS). Although these sensors exhibit excellent photostability in the short-term, long-term exposures (up to 1,000 hr) are shown to detrimentally impact performance via photobleaching phenomenon. We also investigated higher porphyrin concentrations to determine whether the resulting sensors are predisposed to photobleaching. High porphyrin loadings (up to 10 wt%) could be successfully incorporated into the core. While increased probe content should logically enhance emission intensity, we sought to investigate the balance between a stronger signal and the potential for decreased photostability. The resulting behavior is rationalized by (1) establishing the spacing associated with a ‘perfect’ molecular dispersion and (2) invoking five distinct populations of porphyrin agglomeration. Populations that are not molecularly dispersed experience varying degrees of agglomeration-catalyzed photobleaching. The photobleaching rate increases with the extent of agglomeration and, therefore, the initial porphyrin content. Although it is demonstrated that low porphyrin loadings exhibit improved photobleaching resistance, the initial brightness is inadequate. In contrast, enhanced brightness via increased porphyrin content also leads to diminishing returns due to the apparent emergence of a self-quenched population. For a given application, selection of an appropriate porphyrin concentration is critical to achieving a compromise between initial brightness and photobleaching resistance. Detector sensitivity and anticipated duration of use must be considered when weighing the relative benefits of these attributes and selecting a specific porphyrin content.
关键词： Core-shell electrospinning,electrospun nanofiber,agglomeration,porphyrin,oxygen sensing
更新于2025-09-09 09:28:46
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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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[IEEE 2018 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) - Cancun, Mexico (2018.10.21-2018.10.24)] 2018 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) - Piezoelectric Nanofibers for Integration in Multifunctional Materials
摘要： This paper deals with realization of multifunctional composite materials, having piezoelectric effect. First of all polymeric mats of electrospun piezoelectric nanofibers were realized with different geometries. Such effect has been maximized by designing properly the electrospinning apparatus in order to enhance the electric field in the interelectrodic space which polarize the dipolar moments. The mats are then integrated in a silicon rubber matrix and measurements of the electromechanical response of the composite materials thus manufactured are performed. A good integration of nanofibers inside the host material is evidenced by electron microscopy images, allowing delaminations, which could occur using piezoelectric films, to be avoided. A large electrical response to both impact and vibration stimuli has been finally demonstrated.
关键词： electrospinning,piezoelectrics,smart materials,Nanofibers,electric response,PVdF-TrFE
更新于2025-09-04 15:30:14
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Effect of crosslinking stage on photocrosslinking of benzophenone functionalized poly(2-ethyl-2-oxazoline) nanofibers obtained by aqueous electrospinning
摘要： In this study, benzophenone was introduced onto partially hydrolyzed poly(2-ethyl-2-oxazoline) (PEtOx-PEI) to prepare a poly(2-ethyl-2-oxazoline)-benzophenone (PEtOx-BP) copolymer, which was used to produce water stable nanofibers via aqueous electrospinning and photocrosslinking. Three different ultraviolet (UV) irradiation methods, i.e. pre-crosslinking before electrospinning, in-situ crosslinking during electrospinning and post-crosslinking after electrospinning, were used to prepare crosslinked nanofibers. The influence of UV-irradiation at these different stages of the nanofiber production process was investigated in terms of alterations in viscosity, nanofiber morphology and water stability of the fibers. It was shown that pre-crosslinking the polymer solutions had a great influence on the solution viscosity which could both positively or negatively alter the stability of the electrospinning process. Whereas the strategy of crosslinking nanofibers during the production process did not lead to uniform nor water-stable nanofibers, the pre-crosslinking and post-crosslinking strategies greatly increased the water stability of the nanofibers. In both techniques the crosslinking density and therefore water solubility can be easily tuned by manipulating the polymer concentration, UV-irradiation time and membrane thickness. Complete insolubility, i.e. the formation of crosslinked networks, was achieved by the post-crosslinking strategy. This work provides straightforward methods to increase the water stability of the PEtOx nanofibers, which will definitely be of great value to biomedical applications such as drug delivery and tissue engineering.
关键词： nanofibers,benzophenone,crosslinking,UV-irradiation,electrospinning,poly(2-ethyl-2-oxazoline)
更新于2025-09-04 15:30:14
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Investigation on the electrospun PVDF/NP-ZnO nanofibers for application in environmental energy harvesting
摘要： PVDF is one of the most widely used dielectric polymers that has four phases. Among them, only its β phase shows piezoelectric property, which is accessible through an electrospinning synthesis method. In this research, a solution of dimethylformamide (DMF) and tetrahydrofuran (THF), with different ratios, and two different polymer concentrations, as well as various ZnO percentages, were used for synthesis of PVDF/NP-ZnO nano?bers composite. The samples that led to the formation of nano?bers were characterized. The results indicate that nano?bers were appropriately formed at lower concentrations of polymer and zinc oxide with equal ratio of the two solvents. To study the effects of synthesis conditions on the morphology and diameter of the nano?bers, the samples were synthesized at different intervals and at different injection rates. The results show that at lower intervals, the injection rate should be reduced to form more uniform nano?bers without nodes and sprays. Finally, ?exible piezoelectric nanogenerators were fabricated based on the best samples and were tested under vibrational mechanical forces. The results indicate a maximum output power of 32 nW/cm2. The greater output current and voltage were resulted by using more uniform and stretched nano?bers.
关键词： Nano?bers,Nanogenerator,PVDF,ZnO,Electrospinning
更新于2025-09-04 15:30:14
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Development of a nanoscale-based optical chemical sensor for the detection of NO radical
摘要： Nitric oxide is one of the most important biochemical parameters in biological processes; it is also known as carcinogenic. There is need for the design of stable and durable solid phase nitric oxide sensors. In this study, we immobilized the nitric oxide sensitive molecules pyrene, tris(2,2’-bipyrdyl)dichlororuthenium(II) hexahydrate (Ru(bipy) 2+ 3 ) , and magnesium phthalocyanine (Mg-Pc) for the first time in polymeric or glassy matrices. We applied silver nanoparticles and ionic liquids in the fabrication process of polymeric electrospun fibers and thin films. We compared their NO sensitivity in micelle solutions that mimic the cell medium by both steady state and lifetime-based fluorescence measurements. Among the tested dyes, the pyrene exhibited the highest response for radicalic NO. The Mg-Pc dye followed pyrene in terms of sensitivity and exhibited increasing fluorescence intensity and lifetime-based response. Lifetime-based response is advantageous and selective as it is not affected by source variations, photo-bleaching, or leaching effects. Another advantage of Mg-Pc dye is that it is not poisonous for organic systems. Presence of the ionic liquid enhanced the sensor response in all of the test moieties. The obtained limit of detection values for pyrene, Ru(bipy) 2+ and Mg-Pc dyes were 0.15 (cid:22) M, 1.54 (cid:22) M, and 0.78 (cid:22) M, respectively.
关键词： electrospinning,Nitric oxide radical,nanomaterials,ruthenium complex,magnesium phthalocyanine,pyrene,time resolved fluorescence
更新于2025-09-04 15:30:14