Performance Of Nanofibers Research Articles

Development of Polyvinyl Alcohol (PVA) Nanofibers Containing Cationic Lipid/siRNA Complexes via Electrospinning: The Impact of PVA Characterization.

This study aimed to develop polyvinyl alcohol (PVA) nanofibers encapsulating 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/siRNA complexes via electrospinning for the delivery of nucleic acid-based drugs. It also focused on the influence of the intrinsic properties of PVA on the efficacy of the system. PVA nanofibers, with diameters of 300-400 nm, were obtained, within which the siRNA remained intact and the DOTAP/siRNA complexes were uniformly dispersed. By incorporating DOTAP/siRNA complexes into the PVA nanofibers and assessing the impact of their RNA interference (RNAi) activity in A549-Luc cells, a stable inhibition of luciferase expression was observed. An examination of the nanofiber preparation process revealed that even when DOTAP or siRNA were added separately to the PVA solution without forming complexes, the RNAi effect was retained. The DOTAP/siRNA complexes released from the PVA nanofibers were internalized by the cells, with some PVA residues remaining on their surfaces. The significance of the degree of hydrolysis and polymerization of PVA on the performance of nanofibers was highlighted. Notably, PVA with a low degree of hydrolysis substantially enhanced RNAi effects, with luciferase expression inhibition reaching 91.5 ± 0.7%. Nanofibers made of PVA grades with anionic or cationic modifications were also evaluated, suggesting that they affect the efficacy of siRNA delivery. The insights obtained suggest avenues for future research to optimize drug delivery systems further.

In Situ Synthesis of NH2-MIL-53-Al/PAN Nanofibers for Removal Co(II) through an Electrospinning Process.

In this study, researchers developed a novel composite material called NH2-MIL-53-Al/PAN, which consists of metal-organic frameworks (MOFs) grown on electrospun PAN nanofibers (NFs). The successful formation of the composite was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR), and the hydrophilicity of NH2-MIL-53-Al/PAN was demonstrated by the water contact angle (WCA). Batch experiments were conducted to investigate the adsorption performance of Co(II) under different conditions. The maximum adsorption capacity reached 58.72 mg/g, and almost 95% of the adsorption was achieved within the first 6 h. The adsorption process was found to be spontaneous and endothermic and followed the pseudo-second-order kinetics and Langmuir models. Chemisorption and molecular layer adsorption are the main mechanisms of adsorption, and X-ray photoelectron spectroscopy (XPS) analysis further reveals that the interaction between the adsorbent and cobalt is a coordination interaction. In this study, NH2-MIL-53-Al was grown in situ on PAN to ensure effective loading of MOFs and prevent agglomeration during the NF mixing process. This approach successfully addressed the challenge of exposing active sites within the embedded MOF crystals. Additionally, it overcame the difficulty of recycling traditional MOF adsorbents. As a result, the exceptional performance of MOF NFs offers a promising solution for the efficient removal of cobalt-containing wastewater.

Preparation and performance of nanofibers by centrifugal spinning with multi-field coupling

Nanomaterials are used in a variety of fields. As a novel way to produce nanofibers, high-speed centrifugal spinning has attracted wide attention. Nanofibers are widely used in medical transmission, bio-chips, and environmental protection. In high-speed centrifugal spinning production, the quality of nanofibers will be affected by the coupling effects of gravity field, centrifugal position, flow field, temperature and humidity field. The quality of nanofibers will also be affected by the collection distance, motor speed and nozzle structure size. In this paper, the flow of spinning solution in the nozzle is investigated mathematically. Then the solution flow in the nozzle is simulated. Finally, high-speed centrifugal spinning experiments were carried out and nanofiber membranes were collected. The surface quality of the nanofiber membrane was observed by scanning electron microscope (SEM), and the figure of fiber diameter distribution was obtained. Thermogravimetric (TG) analysis shows that the thermal stability and ablative resistance of nanofiber membranes are improved. The results show that the high-speed centrifugal spinning method has high production efficiency. The nanofibers produced by high-speed centrifugal spinning method have good surface quality, uniform diameter distribution and good thermal stability.

Understanding the interplay of solution and process parameters on the physico-chemical properties of ZnO nanofibers synthesized by sol-gel electrospinning

Aging populations and the increase in chronic diseases worldwide demand efficient healthcare tools for simple, rapid, and accurate diagnosis and monitoring the human health. In this context, gas sensors are used to analyze the type of gas in the breath to diagnose chronic diseases. Metal oxide and ceramic nanofibers (NFs) produced by the electrospinning (ES) method have been investigated for potential use as gas sensors in the engineering and medical sectors. The material and process parameters are the main influencing factors on the functional performance of electrospun metal oxide NFs. Zinc oxide (ZnO) based NFs are used in various gas sensors due to the wide band gap (3.37eV), large exciton binding energy, and high mobility of charge carriers of ZnO. In this research, we made an attempt to study the effect of poly(vinyl alcohol) (PVA) and zinc acetate dihydrate (ZnAc2) concentrations and feed rate, voltage, spinneret tip-to-collector distance (TCD), and pyrolysis temperature on the physical properties of ZnO NFs. An average fiber diameter of 119 nm was obtained after pyrolysis at 600 °C of electrospun fiber produced from an aqueous PVA solution of concentration 15 w% with 7.5 w% ZnAc2 based on the weight of PVA. The grain size, transmittance, structural defects, and band gap energy of NFs were found to increase as a function of the pyrolysis temperature, which could be beneficial for the functional applications of these NFs.

Non-Isothermal Crystallization Kinetics of Poly (ɛ-Caprolactone) (PCL) and MgO Incorporated PCL Nanofibers.

The study delves into the kinetics of non-isothermal crystallization of Poly (ɛ-caprolactone) (PCL) and MgO-incorporated PCL nanofibers with varying cooling rates. Differential Scanning Calorimetry (DSC-3) was used to acquire crystallization information and investigate the kinetics behavior of the two types of nanofibers under different cooling rates ranging from 0.5-5 K/min. The results show that the crystallization rate decreases at higher crystallization temperatures. Furthermore, the parameters of non-isothermal crystallization kinetics were investigated via several mathematical models, including Jeziorny and Mo's models. Mo's approach was suitable to describe the nanofibers' overall non-isothermal crystallization process. In addition, the Kissinger and Friedman methods were used to calculate the activation energy of bulk-PCL, PCL, and MgO-PCL nanofibers. The result showed that the activation energy of bulk-PCL was comparatively lower than that of nanofibers. The investigation of the kinetics of crystallization plays a crucial role in optimizing manufacturing processes and enhancing the overall performance of nanofibers.

Space-confined fabrication of hydrophobic magnetic carbon nanofibers for lightweight and enhanced microwave absorption

Advanced microwave absorbers (MAs) containing magnetic particles and carbon nanofibers (CNFs) have raised widespread attention in the rapid popularization of electronic communication equipment. However, it is quite challenging to control the growth of magnetic particles in CNFs to improve electromagnetic waves (EMWs) loss and attenuation. Herein, a novel space-confined strategy was adopted to develop Co/CoO/SiO2/CNFs, in which Co/CoO nanoparticles (NPs) with single domain size and dispersed distribution could achieve enhanced magnetic loss and dielectric loss. The introduction of nano-SiO2 in the system could enhance the dielectric confinement effect of the nanofibers (NFs), while an interfacial confinement network could also be constructed to realize the refinement of Co/CoO NPs, enhance the electromagnetic (EM) loss, and ultimately ameliorate the microwave absorption performance of as-obtained NFs. When the additive amount of nano-SiO2 in the spinning solution was 1.0 mg, the as-prepared Co/CoO/SiO2/CNFs reached the optimal reflection loss (RL) of −52.9 dB at 12.64 GHz with a thickness of 2.5 mm, and the effective bandwidth (EBW) reached 5.67 GHz (10.46–16.13 GHz). Furthermore, the excellent hydrophobic properties of the CNFs endow them with potential self-cleaning function. The confinement strategy proposed in this work lays a foundation for the design of low-filling ratio and high-performance CNFs-based microwave absorbers, and presents a general approach for the synthesis of one-dimensional composite materials with controllable structures.

Adsorption and sustained release of doxorubicin from N-carboxymethyl chitosan/polyvinyl alcohol/poly(ε-caprolactone) composite and core-shell nanofibers

The core-shell nanofibers, produced by the coaxial electrospinning method, are good candidates for delivery of anticancer drugs due to their continuous release without initial burst release. In this work, the N-carboxymethyl chitosan (N-CMCS)-polyvinyl alcohol (PVA)/poly(ε-caprolactone) (PCL) composite and core-shell nanofibers were prepared by two-nozzle and coaxial electrospinning techniques, respectively. Doxorubicin (DOX) as an anticancer drug was loaded into the N-CMCS/PVA/PCL nanofibers fabricated by two-nozzle and coaxial electrospinning. The performance of nanofibers was compared for the adsorption and controlled release of DOX against MCF-7 breast cancer cells death in vitro. The produced fibers were characterized using FTIR, SEM, and TEM analysis. Drug encapsulation efficiency, drug content, and drug release studies were evaluated. The DOX molecules were released from coaxial nanofibers without burst release under extended-release during 20, and 10 days under pH values of 7.4 and 5.5, respectively. The initial burst release at the first hours following by the sustained release of DOX was achieved for composite nanofibers during 11 and 3 days under physiological and acidic pH, respectively. The maximum monolayer sorption capacities of N-CMCS/PVA/PCL composite and core-shell nanofibers for DOX sorption were 74.31 and 40.74 mg g−1, respectively at optimum pH of 8, equilibrium times of 60 min (composite nanofibers) and 120 min (core-shell nanofibers). The maximum MCF-7 breast cancer cells death was about 57% in the presence of DOX loaded-coaxial nanofibers after 7 days. The obtained results demonstrated the high potential of coaxial nanofibers compared with composite nanofibers for drug delivery of anticancer drugs.

Production of red mud based nanofibers and their potential in arsenate removal from waste water

In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber adsorbent in arsenate removal from waste water. RM, obtained from Seydişehir Aluminum Plant (Konya, Turkey), was leached using nitric acid in order to recover metallic elements such as Fe, Al, and Ti. Oxides and hydroxides of these elements are known to have a high affinity toward arsenic. Metallic salt solution, obtained after leaching treatment, was used to produce nanofibers via electrospinning method to get an adsorbent material with high surface area. Compositional, phase structural, microstructural, and thermal analyses were conducted using AAS, XRF, XRD, SEM, and DT/TGA. Organic removal from nanofibers were conducted at 600 °C for 5 h, based on the DT/TGA results. After heat treatment, nanofibers with diameters ranging from 45 to 58 nm were obtained. Performance of nanofibers in As(V) (arsenate) removal from waste water was also evaluated with different amount of nanofibers (1-3 mg/L), arsenate concentration (5-100 ppm), and contact time (10-120 min). Experimental results showed that the fastest and highest removal efficiency (∼80.2%) was obtained for 3 mg/L nanofiber and 10 ppm arsenate concentration at 90 min. Kinetic studies revealed that the pseudo-second-order kinetic model was dominantly active in the adsorption process.

Au-Ru alloy nanofibers as a highly stable and active bifunctional electrocatalyst for acidic water splitting

Bimetallic AuRu alloy nanofibers (NFs) with Au:Ru atomic ratios of 7.5:92.5 are constructed and characterized as a bifunctional electrocatalyst for electrochemical overall water splitting (OWS) of both oxygen (OER) and hydrogen evolution reaction (HER). First, composite NFs consisting of RuO2 fibrous mainframes adorned with tiny Au nanoparticles are synthesized by electrospinning and calcination. The following heat treatment of these composite NFs under H2 gas flowing induces the reduction of RuO2 mainframes to metallic Ru within which Au atoms are dispersed to form homogeneous AuRu alloy NFs regardless of their immiscibility. The OWS activities of prepared AuRu alloy NFs are investigated in 0.5 M H2SO4 aqueous solution; and compared to those of RuO2, Ru, Au, and commercial catalysts, M/C (20 wt% metal loading on Vulcan XC-72 with M = Pt, Ru and Ir). In particular, AuRu alloy NFs show outstanding activity for OER: the lowest overpotential at 10 mA cm−2 and the smallest Tafel slope among the tested catalysts. Of great importance, AuRu alloy NFs also present an excellent long-term stability in a sharp contrast to easily deteriorated Ru-based catalysts (e.g., Ru NFs and Ru/C). AuRu alloy NFs also exhibit good HER activity and stability better than most of tested materials. In a two-electrode system, AuRu NFs ∣∣ AuRu NFs is confirmed to have a lower overpotential for OWS than Ir/C ∣∣ Pt/C, a commercial standard. The OWS performance of AuRu alloy NFs is superior to those of Ru-based bifunctional catalysts found in the literature. HER at AuRu alloy is further studied with density functional theory calculation. The current study reveals Ru alloyed with a small amount of Au having a robust nanofibrous morphology improves the electroactivity and stability for both OER and HER in acidic environments. Given that stable bifunctional catalysts for acidic water splitting have been rarely reported, AuRu alloy NFs exhibit an outstanding feasibility as a practical electrocatalyst for overall water splitting with the high activity and stability.

MoS2 nanosheets-decorated SnO2 nanofibers for enhanced SO2 gas sensing performance and classification of CO, NH3 and H2 gases

The effect of MoS2 nanosheet (NS) decoration on the gas-sensing properties of SnO2 nanofibers (NFs) was investigated. The decorated sensors were fabricated by facile on-chip electrospinning technique and subsequently dropping MoS2 NSs-dispersed solution. The MoS2 NS decoration resulted in enhanced the response and reduced the operating temperature of SnO2 NFs towards SO2 gas. The SnO2 NF sensor decorated with the optimum density of MoS2 NSs exhibited about 10-fold enhancement in gas response to 10 ppm SO2 at 150 °C as compared with the bare SnO2 NF sensor. Furthermore, the decorated sensors exhibited an extremely low detection limit and good selectivity for SO2 gas against other interfering gases, such as CO, NH3, and H2. The enhanced SO2 gas-sensing performance of MoS2 NSs-decorated SnO2 NFs was attributed to the chemical sensitization of MoS2 NSs and charge transfer through heterojunctions between the NSs and SnO2 nanograins. The classification of toxic gases such as CO, H2, and NH3 by the MoS2 NSs-decorated SnO2 NF sensors can achieve high accuracy with linear discriminant analysis (LDA). Our results suggest that the one-dimensional nanostructures of semiconductor metal oxides decorated with two-dimensional transition metal dichalcogenides are attractive candidates for the detection of hazardous gases.

Box‐Behnken Design a Key Tool to Achieve Optimized PCL/Gelatin Electrospun Mesh

AbstractHybrid electrospun nanofibers of polycaprolactone (PCL)/gelatin are considered as drug‐delivery systems for increasing the treatment efficacy in superficial (skin) wounds. Continuous delivery of therapeutic agents, skin extracellular matrix similarity, management of wound exudate, and antimicrobial barrier effect are the major advantages of electrospun nanofibers in skin applications. Additionally, combining the favorable properties of PCL and gelatin, regarding their biocompatibility, biodegradability and mechanical performance have been revealed promising parameters to be considered for blend in hybrid structures. However, the usual optimization protocol of nanofibers’ production in electrospinning is based on the observation of one‐variable‐at‐time being this methodology expensive and time‐consuming. Therefore, in this research work, a statistical model based on four input variables namely, the flow rate, the needle‐working distance, the applied voltage, and the ratio of PCL in the solution, is developed to predict the behavior of nanofibers. The performance of nanofibers is monitored by measurements of fiber's diameter, mesh's thickness, and mesh's permeability. Overall, the model showed to be statistically significant (p‐value < 0.05) and an independent analysis validated the predicted response for optimal condition. Finally, a delivery study is performed to evaluate the electrospun mesh performance as a drug carrier.

Electrospun PVA/hyaluronic acid/L-arginine nanofibers for wound healing applications: Nanofibers optimization and in vitro bioevaluation

Hyaluronic acid (HA) based nanofibers (NFs) represented a novel class of bioactive wound dressings that have a vital role in wound management due to their unique properties as an extracellular-matrix and accelerating wound healing. Novel L-arginine-loaded citric acid crosslinked PVA-HA NFs were fabricated by electrospinning and proposed for potential wound healing purposes. However, poor mechanical properties of HA NFs might limit its biological usage, thus this study aims to develop reinforced PVA/HA NFs by incorporation of cellulose nanocrystals (CNCs) as nanofiller and loading L-arginine as wound healing accelerator. Results revealed that incorporation of CNCs into PVA/HA significantly improved mechanical and swelling properties of NFs, compared to CNC-free NFs. Biological performance of NFs was evaluated on normal human skin melanocyte (HFB-4) and lung fibroblast (WI38) cell-lines. PVA/HA/CNC/L-arginine NFs exhibited excellent hemocompatibility, high protein adsorption, outstanding proliferative and adhesive potential on HFB-4 cells expressed by high wound gap-closure 99.9% after 48 h of exposure. Released arginine from PVA/HA/CNC NFs showed sustained release about 46.5% and ~90% after 24 h and 48 h, respectively. Briefly, PVA/HA/CNCs/L-arginine showed adequate antibacterial activity especially against Klebsiella pneumonia, as an acute popular pathogen causing a skin infection. These results indicate that PVA/HA/CNC/L-arginine could act as promising and multifunctional wound dressings.

Synthesizing BaTiO3 Nanostructures to Explore Morphological Influence, Kinetics, and Mechanism of Piezocatalytic Dye Degradation.

Piezocatalysts have attracted much attention due to their excellent degradation ability for organics. In this work, three types of BaTiO3 (BTO) nanostructures, including hydrothermally synthesized nanocubes (NCs), sol-gel calcined nanoparticles (NPs), and electrospun nanofibers (NFs), are prepared for catalyzing the dye degradation. Compared with the NCs and NPs, the NFs exhibit a higher piezocatalytic degradation performance due to the large specific surface area, fine crystal size, and easy deformation structure. Moreover, the kinetic factors, including initial dye concentration, ionic strength, ultrasonic power, and applied action, influencing the degradation performance of the BTO NFs are analyzed deeply. A high degradation rate constant of 0.0736 min-1 is achieved for rhodamine B, which is superior compared with the previous reports. The excellent stability of BTO NFs is demonstrated by the cycling tests, where a high degradation efficiency of 97.6% within 110 min is still obtained after the third cycle. Furthermore, the mechanism of piezocatalysis revealed that the hydroxyl and superoxide radicals are the main reactive species in the degradation process. This work is of importance for the development of high-performance piezocatalysts and highlights the potential of piezocatalysis for water remediation.

Effect of annealing temperature on charge storage kinetics of an electrospun deposited manganese oxide supercapacitor

Nanofibers (NFs) Mn2O3 thin films are prepared by facial and cost effective single-nozzle electrospinning method. The effect of annealing temperature on structural, morphological and surface analysis of NFs coated thin films are investigated. XRD measurement reveals, the formation of cubic crystalline Mn2O3 above 400 °C annealing temperature. Vibration bonds at 515 and 624 cm−1 confirms the presence of Mn2O3 from Fourier transform infrared spectroscopy studies. Field emission scanning electron spectroscopy analysis shows the NFs like morphology of Mn2O3 are observed after heat treatment. The synthesized NFs have high specific surface area with pore size, which is beneficial for charge storage application. Electrochemical performance of electrospunn Mn2O3 NFs are evaluated by using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. The sample annealed at 300 °C shows maximum specific capacitance of 526 F g−1 at 0.5 mA cm−2 in 1 M aq. Na2SO4 electrolyte. In addition, the NFs sample shows 96% retention in specific capacitance measured up to 1000 CV cycles. The storage of charge due to diffusion and capacitive controlled process are analysed in detail with their percentage contribution. It confirms that, the amorphous Mn2O3 NFs structure have high specific surface area and excellent capacitive performance as compared to crystalline Mn2O3.

Cementitious material reinforced by carbon nanotube-Nylon 66 hybrid nanofibers: Mechanical strength and microstructure analysis

In this study, carbon nanotube (CNT) reinforced Nylon 66 nanofibers were used to modify the mechanical properties of cementitious materials. Single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) were dispersed into the polymer solution of Nylon 66. CNT reinforced Nylon 66 nanofibers were fabricated and mixed directly with ordinary Portland cement through an electrospinning process using an improved collector. Scanning electron microscope (SEM) and field emission transmission electron microscope (FE-TEM) were employed to investigate the morphological characteristics of nanofibers as well as the performance of nanofibers in the microstructure of hardened cement pastes. Moreover, the existence of CNTs in the hardened cement pastes was clarified by means of micro-computed tomography (CT) technique and thermal gravimetric analysis (TGA) method. The observations from mechanical strength tests showed the increase in toughness by 49 %, 30 % and 12 % as well as the increase in the tensile strength by 28 %, 43 % and 57 % in that order when adding Nylon 66 nanofibers, SWCNT reinforced Nylon 66 nanofibers and MWCNT reinforced Nylon 66 nanofibers into cement pastes.

H2S detection capabilities with fibrous-like La-doped ZnO nanostructures: A comparative study on the combined effects of La-doping and post-annealing

Herein, we investigated the H2S gas sensing capabilities of ZnO nanofibers (NFs) prepared via the electrospinning method following La-doping and post-annealing treatment at various doping levels and annealing temperatures, respectively. Following a comparative gas sensing study between the pure and La-doped ZnO NFs based sensors upon exposure to H2S at moderate optimal working temperatures, all La-doped ZnO sensors displayed enhanced sensor responses toward H2S as well as fast response/recovery times as compared to that of the pure ZnO based sensor, respectively. Additionally, apart from the fact that these sensors displayed the highest responses, they also revealed relatively high selective responses to H2S. The sensor based on 2 wt% doping annealed at 900 °C displayed the highest H2S response as well as good repeatability, and stability. These findings indicate that the La-doped ZnO NF based sensors could be a promising gas active/sensing layer for detection of H2S in real environments. Combination of various analysis techniques utilized to understand the influence of La-doping and annealing treatment on the H2S sensing performance of the ZnO NFs revealed that synergetic effects of higher surface area, large number of intrinsic defects and the catalytic activity of La are the main reasons for enhanced H2S response with La doping in this work.

Design of supersensitive and selective ZnO-nanofiber-based sensors for H2 gas sensing by electron-beam irradiation

In the present study, ZnO nanofibers (NFs) were synthesized by the simple electrospinning technique for gas sensing studies. ZnO NFs were irradiated with a high-energy (1 MeV) electron beam (e-beam) at different doses (50, 100, and 150 kGy) to study the effect of the e-beam dose on the sensing performance of the synthesized ZnO NFs. H2 sensing studies showed that the sensing properties of the unirradiated and 50 kGy-irradiated sensors were similar, which indicates that this e-beam dose was insufficient. However, the sensing characteristics improved with an increase in the irradiation dose to 100 and 150 kGy. The response of the optimal sensor (150-kGy-irradiated) to 10 ppm H2 was much higher than that to other (interfering) gases (e.g., C2H5OH, C6H6, C7H8, and CO). The observed high gas response of the 150 kGy-irradiated sensor was attributed to its high surface area resulting from the one-dimensional nature of the ZnO NFs, the grain size of ZnO, and the formation of surface defects by e-beam irradiation. The high selectivity of the ZnO NFs toward H2 gas was related mainly to the metallization of ZnO and the concentration gradient of carfbon across the NF surfaces. Overall, the findings demonstrate the effectiveness of high-energy irradiation in enhancing the sensing performance of ZnO NFs. We believe that this approach can be extended to other metal oxides for the enhancement of sensing performance.

Sensitive and Selective Electrochemical Determination of L‐Cysteine Based on Cerium Oxide Nanofibers Modified Screen Printed Carbon Electrode

AbstractA novel L‐cysteine (CysH) electrochemical sensor based on CeO2 nanofibers (NFs) modified screen printed carbon electrodes (SPCEs) was developed. The morphology and the structure of the as‐prepared CeO2 NFs were first characterized using scanning electron microscopy (SEM) and X‐ray diffraction pattern (XRD), respectively. The electrochemical and electrocatalytic performances of the CeO2 NFs modified SPCEs were then evaluated using cyclic voltammetry and amperometry. Experimental results showed that the CeO2 NFs modified SPCEs possess excellent electrocatalytic activity toward the detection of CysH. Specifically, the developed electrochemical sensor demonstrated a high sensitivity of 120 μA mM−1 cm−2, a low detection limit of 20 nM (signal to noise ratio of 3) and a wide linear range up to 200 μM for the determination of CysH, which are among the best values reported in literature. In addition, good selectivity and outstanding intra‐ and inter‐electrode reproducibility have also been observed. Furthermore, the developed CysH sensor was applied to detect CysH spiked into human serum samples with remarkable accuracy. All these features indicate that CeO2 NFs hold great promise in the development of high performance electrochemical sensor for CysH.

Electrocatalytic behavior of a nanocomposite of Ni/Pd supported by carbonized PVA nanofibers towards formic acid, ethanol and urea oxidation: A physicochemical and electro-analysis study

A nanocomposite of Ni/Pd supported by carbonized poly-vinyl alcohol (PVA) nanofibers (NFs) was synthesized via electrospinning followed by calcination under an argon atmosphere. The as-synthesized NFs were studied using physicochemical analyses, such as field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), to investigate the morphology, crystallinity, effect of carbonization and surface chemistry of the NFs, respectively. Cyclic voltammetry (CV) and chronoamperometry (CA) were utilized to study the performance of the NFs towards electrooxidation reactions. The designed NFs present superior electrocatalytic behavior in an acid medium towards formic acid oxidation, as well as urea and ethanol oxidation in an alkaline medium. The electrocatalytic performance of the bimetallic NFs appears to arise from the assembly of bimetallic Ni/Pd@NFs based on PVA, which has hydroxyl groups. These hydroxyl groups can decrease the negative processes that occur as a result of metal-metal interactions, such as the aggregation process. This study introduces a novel non-precious electrocatalyst to facilitate the commercialization of fuel cells based on formic acid, urea and ethanol.

Graphene-loaded tin oxide nanofibers: optimization and sensing performance

We investigated the gas sensing characteristics of graphene nanosheet (NS)-loaded SnO2 nanofibers (NFs) that were synthesized by a low-cost facile electrospinning process. The sensing performance was characterized as a function of the graphene content with various gases such as C6H6, C7H8, CO, CO2, and H2S. The loading of graphene NSs significantly improved the gas sensing performances of SnO2 NFs. The optimal amount of graphene NSs was found to be 0.5 wt%. We proposed a sensing mechanism for the enhanced sensing performance based on the chemical sensitization of graphene NSs and the charge transfer through the heterointerfaces between graphene NSs and SnO2 nanograins. The results show that graphene NS-loaded SnO2 NFs are a promising sensing material system that can detect hazardous gaseous species.