Direct Electrospinning Research Articles

MXene nanosheets woven in polyacrylonitrile nanofiber yarns aligned spider web as a highly efficient sorbent for in-tube solid phase microextraction of beta-blockers from biofluids

The use of electrospinning has received much attention in the production of nanofiber webs due to its advantages such as flexibility and simplicity. The direct electrospinning of nanofibers in an aligned or twisted form and the production of nanofiber yarns can turn nanofibers into woven fabrics, which leads to an increase in the diversity of nanofiber applications and improves their end-use possibilities. In this work, a victorious nanofiber yarn spinning system was used with the help of a rotating funnel. Yarn formation was studied using a composited polyacrylonitrile (PAN)/MXene polymer solution ejected from two oppositely charged nozzles. Finaly their application for packed-in-tube solid-phase microextraction of β-blocker drugs from biofluids was demonstrated. The separation and quantification of analytes were performed by HPLC-UV instrument. The 3D-yarn PAN/MXene sorbent exhibited high flexibility, porosity, sorbent loading, mechanical stability, and a long lifetime. The characterization of the final nanofiber was carried out utilizing Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray mapping, transmission electron microscope and X-ray diffraction analysis. Various parameters that affect the extraction efficiency, such as extraction time, pH, ionic strength and flow rate of sample solution, and type, volume and flow rate of eluent, were investigated and optimized. Under optimized conditions, the limits of detection were obtained in the range of 1.5–3.0 μg L−1. This method demonstrated appropriate linearity for β-blockers in the range of 5.0–1000.0 μg L−1, with coefficients of determination greater than 0.990. The inter- and intra-assay precisions (RSDs, for n = 3) are in the range of 2.5–3.5%, and 4.5–5.2%, respectively. Finally, the validated method was put in an application for the analysis of atenolol, propranolol and betaxolol in human urine and saliva samples at different hours and acceptable relative recoveries were obtained in the range of 89.5% to 110.4%.

Ultralight and Superelastic Curly Micro/Nanofibrous Aerogels by Direct Electrospinning Enable High-Performance Warmth Retention.

Extremely low temperature has posed huge burden on the public safety concerns and global economics, thereby calling for high-performance warmth retention materials to resist harsh environment. However, most present fibrous warmth retention materials are limited by their large fiber diameter and simple stacking structure, leading to heavy weight, weak mechanical property, and limited thermal insulation performance. Herein, an ultralight and mechanically robust polystyrene/polyurethane fibrous aerogel by direct electrospinning for warmth retention is reported. Manipulation of charge density and phase separation of charged jet allows for the direct assembly of fibrous aerogels consisting of interweaved curly wrinkled micro/nanofibers. The resultant curly wrinkled micro/nanofibrous aerogel possesses low density of 6.8mgcm-3 and nearly full recovery from 1500-cycle deformations, exhibiting both ultralight feature and superelastic property. The aerogel also shows low thermal conductivity of 24.5mWm-1 K-1 , making synthetic warmth retention materials superior to down feather possible. This work may shed light on developing versatile 3Dmicro/nanofibrous materials for environmental, biological, and energy applications.

Heat-conducting elastic ultrafine fiber sponges with boron nitride networks for noise reduction

Industrial and traffic noise has become increasingly serious with the progress of industrialization. Most existing noise-absorbing materials suffer from poor heat dissipation and insufficient low-frequency (<1000 Hz) noise absorption, which not only reduces working efficiency but also leads to safety risks. Herein, heat-conducting elastic ultrafine fiber sponges with boron nitride (BN) networks were prepared by integrating direct electrospinning and impregnation method. The large acoustic contact area of ultrafine fibers and the vibration effect of BN nanosheets in a three-dimensional direction endow fiber sponges with good noise reduction, which can reduce white noise by 28.3 dB with a high noise reduction coefficient of 0.64. Moreover, thanks to good heat-conducting networks composed of BN nanosheets and porous structures, the obtained sponges exhibit superior heat dissipation with thermal conductivity of 0.159 W m−1 K−1. Besides, the introduction of elastic polyurethane and following crosslinking endow the sponges with good mechanical properties, which have almost no plastic deformation after 1000 compressions, and the tensile strength and strain are as high as 0.28 MPa and 75%. The successful synthesis of heat-conducting elastic ultrafine fiber sponges overcomes poor heat dissipation and low-frequency noise reduction of noise absorbers.

Coaxially electrospun TiO2@Au core-shell nanofibers for ultrasensitive and reusable SERS detection of furazolidone

We report the core/shell synthesis of TiO2 nanofibers covered with Au nanograins (Au NGs@TiO2 NFs) by the direct coaxial electrospinning method without the need of pre-preparation of Au NGs for the rapid and sensitive SERS detection of furazolidone (FZD). The characterization of the as-synthesized Au NGs@ TiO2 NFs hybrid nanostructure was meticulously examined by diverse microscopic and spectroscopic techniques. The SERS performance of Au NGs@TiO2 NFs for the detection of FZD is verified with the high enhancement factor of 5.96 × 1012 and the limit of detection as low as 3.94 × 10−13 M, which are superior to those reported so far in the literatures. The excellent SERS performance can be attributed to the synergistic effect of electromagnetic enhancement and charge transfer induced in the Au NGs@TiO2 NFs hybrid nanostructure. Besides, the Au NGs@TiO2 NFs display good uniformity and high reproducibility for the FZD detection. In the practical application, the Au NGs@TiO2 NFs based SERS substrate is successfully utilized to detect FZD in food and environmental samples with excellent recovery. The reusability measurement shows that 92.73 % of the original Raman peak intensity is retained after five photocatalytic degradation cycles, which confirms the cost effectiveness of Au NGs@TiO2 NFs in the SERS application. The proposed high-performance SERS substrate has great potential to pave a new avenue in food safety applications, such as detecting antibiotics in real samples.

Ultralight and antibacterial fibrous sponges with interlaced crimped-fiber architecture for high-efficiency warmth retention

High-efficiency warmth retention materials are urgently needed by human living in extremely cold environment to maintain their health and physical function. However, most existing fibrous warmth retention materials suffer from large weight, inefficient warm retention performance, and poor antibacterial ability. Here, we propose an innovative strategy to construct ultrafine fibrous sponges with interlaced crimped-fiber architecture by direct electrospinning technology. The stable three-dimensional (3D) network structures assemble from tangly curled ultrafine fibers, endowing the obtained sponges with ultralight characteristics (4.5 mg cm−3), robust elastic resilience (nearly full recovery from 100-cycle compressive deformations), and low thermal conductivity (24.1 mW m−1 K−1). Moreover, the in situ doping of chlorhexidine and fluoropolymer enables the sponges with efficient and durable antibacterial performance after washing processes (antibacterial rate up to 95.6% after 10 recycle washing experiments). This work opens a new way for the design of 3D fibrous materials with remarkable antibacterial performance for various fields.

Direct jet coaxial electrospinning of axon-mimicking fibers for diffusion tensor imaging.

Hollow polymer microfibers with variable microstructural and hydrophilic properties were proposed as building elements to create axon-mimicking phantoms for validation of diffusion tensor imaging (DTI). The axon-mimicking microfibers were fabricated in a mm-thick 3D anisotropic fiber strip, by direct jet coaxial electrospinning of PCL/polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide (PEO) as core. Hydrophilic PCL-PSi fiber strips were first obtained by carefully selecting appropriate solvents for the core and appropriate fiber collector rotating and transverse speeds. The porous cross-section and anisotropic orientation of axon-mimicking fibers were then quantitatively evaluated using two ImageJ plugins-nearest distance (ND) and directionality based on their scanning electron microscopy (SEM) images. Third, axon-mimicking phantom was constructed from PCL-PSi fiber strips with variable porous-section and fiber orientation and tested on a 3T clinical MR scanner. The relationship between DTI measurements (mean diffusivity [MD] and fractional anisotropy [FA]) of phantom samples and their pore size and fiber orientation was investigated. Two key microstructural parameters of axon-mimicking phantoms including normalized pore distance and dispersion of fiber orientation could well interpret the variations in DTI measurements. Two PCL-PSi phantom samples made from different regions of the same fiber strips were found to have similar MD and FA values, indicating that the direct jet coaxial electrospun fiber strips had consistent microstructure. More importantly, the MD and FA values of the developed axon-mimicking phantoms were mostly in the biologically relevant range.

Green Fabrication of Anticorrosive, Antibacterial, and SERS Active Nanohybrid Coatings by Dual-Spinneret Electrospinning

The development of sustainable and nontoxic corrosion coatings in abiotic and biotic environments has recently attracted significant attention. Herein, we developed nanohybrid coatings containing polysulfone (PSU), cyclodextrin (CD), zeolite (10 μm size), and biogenic silver nanoparticles (AgNPs, 40 nm diameter) via direct one-step dual-spinneret electrospinning. In the fabricated nanohybrid coatings, zeolites were used as a nontoxic anticorrosive inhibitor, and biogenic AgNPs serve as antibacterial agents due to their environmentally friendly and low-cost characteristics. Scanning electron microscopy and transmission electron microscopy analyses indicated that the zeolite and AgNP-embedded nanofibers have homogeneous and bead-free morphologies. Moreover, the elemental distribution mapping of the fabricated platforms demonstrated a well-distributed mixture of PSU/zeolite and CD/AgNPs in the nanofiber mats which were fabricated via such a dual-spinneret technique. The surface-enhanced Raman scattering activities of the fabricated nanofiber mats were also evaluated using methylene blue, rhodamine 6 G, crystal violet, and malachite green as probe molecules. Additionally, the antibacterial response of the fabricated nanohybrid coatings against four pathogenic bacteria (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 23213, Pseudomonas aeruginosa ATCC 27853, and Klebsiella pneumoniae ATCC 700603) was investigated, which indicated the critical role of zeolite/AgNPs in suppressing the bacterial growth. Tafel measurements also showed that the PSU/zeolite/HPβCD/AgNPs hybrid coating reduced the corrosion current density of the Cu surface in the presence of P. aeruginosa ATCC 27853, which is a biofilm-producing bacteria, compared to the uncoated surface. The antimicrobial and corrosion inhibition ability of the fabricated nanohybrid coatings offers promising opportunities for the microbiologically influenced corrosion inhibition applications.

Sulfonated silica-based cation-exchange nanofiber membranes with superior self-cleaning abilities for electrochemical water treatment applications

Electrochemical treatments in (waste)water management show high potential in the global water resource crisis, but are often limited by the ion-exchange membrane (IEM) performance. Low chemical resistance and fouling are major issues in the development of next-generation IEMs. Sulfonated silica-based nanofiber cation-exchange membranes (CEMs) offer a promising solution to these issues due to their superior chemical resistance and self-cleaning properties. Via the direct electrospinning of a sol–gel solution starting from tetraethyl orthosilicate (TEOS) and 3-mercaptopropyl triethoxysilane (MPTES), nanofiber membranes with an ion-exchange capacity (IEC) of 1.3 mmol g−1 can be produced without the need of an additional matrix. The produced nanofiber CEM performs excellent in lab-scale electrochemical tests, with a resistance of 3.2 ± 0.4 *10-3 Ω m2 and a Coulombic efficiency of ± 70 % for the transport of Na+ using a current density of either 128 or 256 A/m−2.Furthermore, the nanofiber CEM shows outstanding resistance against strong acidic solutions and chlorine. After fouling of the membrane with CaCO3, the nanofiber CEM shows self-cleaning properties, eliminating the need for an additional cleaning step during usage. These results illustrate the excellent performance of the silica-based nanofiber CEM for industrial water treatment applications.

A new strategy for direct solution electrospinning of phosphorylated poly(vinyl chloride)/polyethyleneimine blend in alcohol media

Phosphorylated poly(vinyl chloride) (PPVC)/polyethyleneimine (PEI)-based nanofibers were produced via electrospinning in their blended solutions for the first time. For this purpose, PVC was partially converted into PVC-N3 and the PVC-N3 is then reacted with bis(diethoxyphosphoryl) acetylene (BDPA) via metal-free azide–alkyne 1,3-dipolar cycloaddition reaction to achieve the alcohol-soluble PPVC. PPVC and PEI solutions at certain concentrations prepared in methanol were electrospun from a single syringe at 90/10 and 85/15 vol ratios without phase separation. The accuracy of the modifications conducted on PVC was proven by Fourier-transform infrared (FT-IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopies and gel permeation chromatography (GPC), respectively. The achieved nanofibers and their intermediates were characterized by scanning electron microscope (SEM), water contact angle (WCA) measurement, thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses.The blood interaction of PPVC-PEI was evaluated through hemolysis and platelet activation assay, since most of the biomedical applications of PVC derivatives have close contact with blood. The results showed that PPVC-PEI nanofibers provide a safer surface for platelet with lower hemolytic activity compared to PPVC nanofibers. Therefore, PPVC-PEI-based electrospun nanofibers obtained by such an effective strategy exhibited a promising perspective for scientists in various biomedical purposes.

Colorimetric active carboxymethyl chitosan/oxidized sodium alginate-Oxalis triangularis ssp. papilionacea anthocyanins film@gelatin/zein-linalool membrane for milk freshness monitoring and preservation

Colorimetric active double-layer composites of film@membrane were developed via direct electrospinning functional nanofibers on colorimetric film. In the structure, oxidized sodium alginate cross-linked carboxymethyl chitosan (CO) was used as colorimetric film matrix to incorporate the anthocyanins extract from Oxalis triangularis ssp. papilionacea (OTA); while the blend of gelatin/zein (GZ) was used as fibrous matrix for linalool (L) encapsulation. Besides good barrier and water resistance, the outer-layer of CO-OTA showed colorimetric sensitivity towards pH-stimuli with reversible color changes. The inner-layer of GZ-L exhibited good antibacterial activities against Staphylococcus aureus and Escherichia coli. The volatile release of L from fibrous matrix was well controlled and mainly followed Fickian diffusion. Moreover, the antioxidant activity of the composites is source from the released linalool. The high reliability on milk freshness monitoring and double shelf-life extending at 25 °C suggest the potential of CO-OTA@GZ-L in colorimetric active food packaging.

Biomimicking tendon by electrospinning tissue‐derived decellularized extracellular matrix for tendon tissue engineering

AbstractTendon injuries disturb the equilibrium between mobility and stability, resulting in impaired functions and disabilities. Clinically, it is still challenging to regenerate fully functional tendons. Here, by direct electrospinning, we fabricate goat tendon‐derived extracellular matrix (tdECM) fibers using polycaprolactone (PCL) as a supporting polymer. We observe that the incorporation of tdECM particles strongly influences the characteristics of the scaffold, such as wettability, water uptake ability, and mechanical properties. The contact angle of the PCL/tdECM scaffold decreases to zero as compared to 122° for only PCL, making the scaffold completely hydrophilic. The water uptake ability increases by 200% by adding tdECM. The Physicochemical properties are evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Electrospun fibers mimic the natural ECM structure, while tdECM can provide biochemical cues for the human mesenchymal stem cells to adhere to and differentiate. The scaffolds positively influence cell survival, proliferation, and alignment along the scaffolds of the human umbilical cord‐derived mesenchymal stem cells (hUMSCs). This study demonstrates the potential of electrospun ECM/polymer as a bioactive scaffold for in situ tendon regeneration.

Design and one-pot direct electrospinning construction of high-performance magnetic@conductive@fluorescent tri-coaxial microbelts and array

Multifunctional materials have more extensive applications than their counterpart single-functional materials due to their superior polyfunctions, among which fluorescent-conductive-magnetic (FCM) multifunctional materials have been extensively investigated for their unique performance and application value. However, the material properties may be degraded due to the adverse interactions among the fluorescent, conductive and magnetic materials with three different functions when they are directly blended. Hence, such adverse interactions brought by the direct contact of different functional materials should be avoided by designing and preparing unique structures. In this study, a one-dimensional (1D) tri-coaxial microbelt is innovatively designed, which can effectively separate and integrate different materials at the micro-level to obtain excellent macroscopic polyfunction. Generally, the preparation of tri-coaxial structure requires multistep procedures. To facilely construct the designed tri-coaxial microbelt, as a case study, a novel [CoFe2O4/polymethyl methacrylate (PMMA)]@[polyaniline (PANI)/PMMA]@[Tb(acac)3bpy/PMMA] (defined as [M@C@F]) tri-coaxial microbelts and arrays are synthesized through the one-pot direct electrospinning (ES) process. The tri-coaxial microbelts are assembled by the CoFe2O4/PMMA magnetic core layer, the PANI/PMMA conductive intermediate layer, and the Tb(acac)3bpy/PMMA insulated-fluorescent shell layer. It is the first time to integrate three different functions into the tri-coaxial microbelts and restrict three functions into three independent zones in the microbelt to shun adverse mutual interferences. The function of each layer can be regulated by adjusting the position and content of the three functional materials. Comparison with the control samples indicates that the property of the tri-coaxial microbelts array is directly impacted by structure and the arrangement modes of the building units. Hence, excellent macroscopic polyfunctions are obtained via designing and preparing microscopic partitioned building units and arranged modes. Array displays superior green fluorescence at 549 nm, tunable electrical conduction and magnetism. The new technique of one-pot direct construction of the tri-coaxial microbelts is significant and can be extended to for assemble other multifunctional materials. Moreover, the constructed [M@C@F] tri-coaxial microbelts and arrays have applications in various fields, such as micro-integrated circuits, microchips, and micro/nanodevices.

Direct electrospinning of fluorine-free waterproof polyamide/polydimethylsiloxane nanofibrous membranes with highly breathable performance

Waterproof and breathable membranes (WBMs) are highly desirable for protective textiles; however, the practical application of existing polyamide nanofibrous WBMs is limited by poor breathability, complicated post-treatments, and toxic-solvent processing. Herein, we present unique fluorine-free polyamide/polydimethylsiloxane (PA/PDMS) composite nanofibrous WBMs by direct electrospinning using alcohol-based green solvents. Highly interconnective channels with robust hydrophobicity are constructed within polyamide nanofibrous WBMs with in-situ incorporation of PDMS by one-step spinning without any post treatments. The resulting PA/PDMS membranes exhibit outstanding air permeability (12.7 mm s−1), high moisture permeability (3.77 kg m−2 d−1), and good hydrostatic pressure (28.3 kPa), suggesting promising utility for outdoor clothing, medical gowns, and wound dressings. The successful synthesis of alcohol-solvent-based fluorine-free PA/PDMS nanofibrous WBMs by facile direct spinning strategy may pave a new way to develop future green polyamide textiles.

CO2 methanation with Ru@MIL-101 nanoparticles fixated on silica nanofibrous veils as stand-alone structured catalytic carrier

An important challenge in the valorization of CO2 and H2 into fuels is the development of a stable, reusable and easy to handle heterogeneous catalyst. Here, a silica nanofibrous membrane is investigated as carrier for Ru nanoparticles, themselves encapsulated inside the metal organic framework (MOF) Cr-MIL-101. The catalytic membrane is investigated for the Sabatier methanation reaction. The direct electrospinning of a tetraorthosilicate (TEOS) sol results in a highly thermal resistant silica nanofibrous structure (up to 1100 °C) with pores between the fibers in the µm-range, allowing a high gas throughput with low pressure requirements. A straightforward dip-coating procedure of the carrier was used to obtain a Ru@MIL-101 functionalized silica nanofibrous veil, avoiding Ru clustering. The obtained catalytic membrane exhibited an apparent turnover frequency of 3257 h-1 at 250 °C. This system therefore paves the way towards structured reactors for efficient CO2 hydrogenation processes.

Environmentally Friendly Polyamide Nanofiber Membranes with Interconnective Amphiphobic Channels for Seawater Desalination.

Seawater desalination is a promising and sustainable solution to alleviate freshwater scarcity; however, most existing desalination membranes suffer from poor channel interconnectivity and toxic solvent processing and encounter a tradeoff dilemma of salt rejection and water flux. Herein, we report a unique and facile one-step green solvent/nonsolvent spinning methodology to assemble environmentally friendly polyamide nanofiber membranes with a precisely designed interconnective/stable channel structure and surface anti-wettability for seawater desalination. Direct electrospinning without any post-treatments via in situ introduction of fluorinated chemicals enables highly interconnective amphiphobic channels within polyamide membranes, and the incorporation of nonsolvent (diacetone alcohol) into polyamide/solvent (ethanol) spinning solutions endows the green alcohol-based polyamide membranes with a stable bonding structure and small pore size. The resultant green solvent/nonsolvent-spun polyamide nanofiber membranes show impressive liquid entry pressure (120.5 kPa) and vapor permeation (12.5 kg m-2 d-1), achieving robust seawater desalination performance with a salt rejection of 99.97% and permeate flux of 47.4 kg m-2 h-1. The facile one-step solvent/nonsolvent spinning strategy, highly interconnective amphiphobic channels, and green solvent-based environmental friendliness in this work can open opportunities for future polyamide membranes for practical applications in water purification.

Facile Preparation of Fluorine‐Free, Heat‐Resisting, Breathable, and Waterproof Nanofibrous Membranes from Polymers of Intrinsic Microporosity

AbstractWaterproof and breathable membranes (WBMs) are widely applied in garment, electronics, and aerospace, however, it is challenging to fabricate WBMs by a facile and successive strategy with excellent comprehensive properties, including environmental friendliness, heat‐resistance, waterproofness, breathability, and mechanical properties. Herein, a straightforward method is developed to fabricate large‐sized WBMs with outstanding integrated performance by direct electrospinning of original polymerization solution from polymers of intrinsic microporosity (PIMs). As‐prepared nanofibrous WBMs perform comprehensive properties with the absence of fluorine, average nanofiber diameters of 278 nm, waterproofness of 88.7 kPa, breathability of 11.2 kg m−2 d−1, tensile strength of 4.2 MPa, and heat‐resistance of 200 °C, which are superior to most of that reported fluorine‐free WBMs. Most significantly, the avoidance of tedious and intermittent fabrication procedures to prepare high‐performant WBMs allows the achievement of the successive production, and the high heat‐resistance meets the requirement of harsh service conditions. This work not only confirms that PIMs can be a good candidate for preparing high‐performant WBMs, but also paves a new version for fabricating environmental benign WBMs in a facile and successive approach.

Superelastic, ultralight, and washable electrospun fibrous sponges for effective warmth retention

Ultrafine fibrous sponges with efficient heat retention capability enable applications in various fields but are hindered due to their poor washability and weak mechanical properties. Here, we develop high-performance electrospun fibrous sponges with superelasticity, washable durability, and effective warmth retention performance by combining direct electrospinning and post-imidization treatment. The incorporation of mechanically robust polyimide and the low surface energy fluorinated polyurethane imparts the fluffy sponges with desired structural stability and high hydrophobicity. Significantly, the obtained sponges exhibit robust resilience (∼4% plastic deformation after 100 compressive cycles), ultralight property (3.6 mg cm−3), effective thermal retention with thermal conductivity of 25.5 mW m−1 K−1, and outstanding washability with maintaining almost unchanged structures and performances after cyclic washing. The successful synthesis of such intriguing fibrous sponges could serve as a guide for designing the next-generation washable warmth retention materials.

The Direct Electrospinning and Manipulation of Magic‐Sized Cluster Quantum Dots

Electrospinning fibers of only quantum dots and their ligands allows hierarchical organization spanning 6+ orders of magnitude. Further details on the process and various levels of organization can be found in article number 2100661 by Tobias Harnath, Richard D. Robinson, Larissa M. Shepherd, and co-workers.

Superelastic and Fire-Retardant Nano-/Microfibrous Sponges for High-Efficiency Warmth Retention

Warmth retention equipment for personal cold protection is highly demanded in freezing weather; however, most present warmth retention materials suffer from high thermal conductivity, weak mechanical properties, and strong flammability, resulting in serious security risks. Herein, we report a facile strategy to fabricate nano-/microfibrous sponges with superelasticity, robust flame retardation, and effective warmth retention performance via direct electrospinning. The three-dimensional fluffy sponges with low volume density and high porosity are constructed by accurately regulating the relative humidity; meanwhile, the mechanically robust polyamide-imide nanofibers with high limit oxygen index (LOI) are innovatively introduced to improve the structural stability and flammability of the nano-/microfibrous sponges. Strikingly, the developed nano-/microfibrous sponges exhibit ultralight characteristics (6.9 mg cm-3), superelasticity (∼0% plastic deformation after 100 compression tests), effective flame retardant with LOI of 26.2%, and good heat preservation ability (thermal conductivity of 24.6 mW m-1 K-1). This work may shed light on designing superelastic and flame-retardant warmth retention materials for various applications.

Electrospinning preparation of g-C3N4/Nb2O5 nanofibers heterojunction for enhanced photocatalytic degradation of organic pollutants in water

In this study, graphitic carbon nitride (g-C3N4) and niobium pentoxide nanofibers (Nb2O5 NFs) heterojunction was prepared by means of a direct electrospinning approach combined with calcination process. The characterizations confirmed a well-defined morphology of the g-C3N4/Nb2O5 heterojunction in which Nb2O5 NFs were tightly attached onto g-C3N4 nanosheets. Compared to pure g-C3N4 and Nb2O5 NFs, the as-prepared g-C3N4/Nb2O5 heterojunction exhibited remarkably enhanced photocatalytic activity for degradation of rhodamine B and phenol under visible light irradiation. The enhanced catalytic activity was attributed predominantly to the synergistic effect between g-C3N4 sheets and Nb2O5 NFs, which promoted the transferring of carriers and prohibited their recombination, confirmed by the measurement of transient photocurrent responses and photoluminescence spectra. In addition, the active species trapping experiments indicated that superoxide radical anion (·O2–) and hole (h+) were the major active species contributing to the photocatalytic process. With its high efficacy and ease of preparation, g-C3N4/Nb2O5 heterojunction has great potentials for applications in treatment of organic pollutants and conversion of solar energy.