Graphene Oxide Nanofibers Research Articles

Construction of ultrasensitive electrochemical sensor using TiO2-reduced graphene oxide nanofibers nanocomposite for epinephrine detection

A facile sensing platform was established for the electrochemical detection of epinephrine using titanium dioxide-reduced graphene oxide nanofibers (TiO2-rGO NFs) nanocomposite modified glassy carbon electrode. The TiO2-rGO NFs were prepared using electrospinning followed by hydrothermal method, characterized by various state-of-the-art techniques, and the fabricated sensor were characterized by cyclic voltammetry and differential pulse voltammetry. Using the optimal experimental conditions potential scan rate, linear correlation between analytical signal and concentration of 10–100 nM with a detection limit of 8.11 nM, and sensitivity 0.126 µA µM−1 were observed. The constructed sensor were evaluated the sensing of epinephrine in human serum and drug injection samples. The developed electrochemical sensor provides a potential candidate for the accurate sensing of epinephrine in biological fluids and pharmaceutical drugs.

Heparin-coated Poly(ethylene terephthalate)/Graphene Oxide Nanofibers Used for Vascular Tissue Engineering Application

Heparin-coated Poly(ethylene terephthalate)/Graphene Oxide Nanofibers Used for Vascular Tissue Engineering Application

Synthesis and antimicrobial studies of nano-copper doped carbon substrates; activated carbon, reduced graphene oxide, and carbon nanofiber

Copper oxides (CuxO) have received considerable attention as a result of their biological activity. Nanoparticles (NPs) of CuxO attached to different substrates exhibit a wide spectrum of antimicrobial activity against bacteria and viruses, with similar properties to silver. The antimicrobial activity of CuxO-NPs doped on distinctive carbon materials was investigated for three carbon substrates: apricot stone activated carbon (AAC), reduced graphene oxide (rGO) and carbon nanofiber (CNF). The CuxO-NPs (5 wt%) doped AAC and rGO substrates were prepared by impregnation of copper nitrate followed by a thermal treatment process, while a similar weight of CuxO-NPs doped CNF was fabricated by electrospinning copper nitrate with polyacrylonitrile precursor, followed by carbonization. The CuxO species and chemical functions were characterized by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Surface morphology was measured using scanning electron microscopy. The antimicrobial activities of the substrates were evaluated by inhibition zone measurement of Staphylococcus aureus and Escherichia coli. The results demonstrated significant inhibition distances for different carbon substrates. Interestingly, CuxO-NPs doped over both AAC and rGO surfaces revealed clear zones against bacteria, whereas the inhibition zone was not recorded for CuxO-NPs doped over a CNF substrate. Various parameters such as carbon substrates, particle size, and copper oxide species were investigated.

Electrically conductive carbon-based (bio)-nanomaterials for cardiac tissue engineering.

A proper self-regenerating capability is lacking in human cardiac tissue which along with the alarming rate of deaths associated with cardiovascular disorders makes tissue engineering critical. Novel approaches are now being investigated in order to speedily overcome the challenges in this path. Tissue engineering has been revolutionized by the advent of nanomaterials, and later by the application of carbon-based nanomaterials because of their exceptional variable functionality, conductivity, and mechanical properties. Electrically conductive biomaterials used as cell bearers provide the tissue with an appropriate microenvironment for the specific seeded cells as substrates for the sake of protecting cells in biological media against attacking mechanisms. Nevertheless, their advantages and shortcoming in view of cellular behavior, toxicity, and targeted delivery depend on the tissue in which they are implanted or being used as a scaffold. This review seeks to address, summarize, classify, conceptualize, and discuss the use of carbon-based nanoparticles in cardiac tissue engineering emphasizing their conductivity. We considered electrical conductivity as a key affecting the regeneration of cells. Correspondingly, we reviewed conductive polymers used in tissue engineering and specifically in cardiac repair as key biomaterials with high efficiency. We comprehensively classified and discussed the advantages of using conductive biomaterials in cardiac tissue engineering. An overall review of the open literature on electroactive substrates including carbon-based biomaterials over the last decade was provided, tabulated, and thoroughly discussed. The most commonly used conductive substrates comprising graphene, graphene oxide, carbon nanotubes, and carbon nanofibers in cardiac repair were studied.

γ-Irradiation crosslinking of graphene oxide/cellulose nanofiber/poly (acrylic acid) hydrogel as a urea sensing patch

Poly (acrylic acid) (PAA) nanocomposite hydrogel was fabricated as a sensing patch for non-invasive dual detection of urea in sweat. The hydrogel was prepared by γ-irradiation crosslinking of PAA solution incorporated with graphene oxide (GO) and cellulose nanofiber (CNF). With high water-sorption capacity and transparency, the hydrogel was suitable to accommodate coloring reagents and enzymes for colorimetric sensing of urea in sweat. The colorimetric sensor exhibited vivid color change towards the increase of urea concentration in a linear range of 40–80 mM covering a cut-off value (60 mM) for chronic kidney disease (CKD) indication. Furthermore, the hydrogel could be directly applied as a substrate for direct quantitation of urea in sweat by laser desorption ionization mass spectroscopy (LDI-MS). While CNF improved the mechanical properties of the hydrogel, GO played a key role in enhancing laser desorption ionization of urea in LDI-MS and increased the hydrogel functionalities. LDI-MS verified that GO/CNF/PAA hydrogel could act as a direct matrix for promoting urea ionization and these results corresponded well with the colorimetric sensor. Hence, this hydrogel patch might be a potential material to be applied in non-invasive and dual-detection of CKD in medical diagnosis.

Graphene Oxide versus Carbon Nanofibers in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Films: Degradation in Simulated Intestinal Environments.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a microbial biodegradable polymer with a broad range of promising industrial applications. The effect of incorporation of low amounts (1% w/w) of carbon nanomaterials (CBNs) such as 1D carbon nanofibers (CNFs) or 2D graphene oxide (GO) nanosheets into the PHBV polymer matrix affects its degradation properties, as it is reported here for the first time. The study was performed in simulated gut conditions using two different media: an acidic aqueous medium (pH 6) and Gifu anaerobic medium. The results of this study showed that the incorporation of low amounts of filamentous 1D hydrophobic CNFs significantly increased the degradability of the hydrophobic PHBV after 3 months in simulated intestinal conditions as confirmed by weight loss (~20.5% w/w in acidic medium) and electron microscopy. We can attribute these results to the fact that the long hydrophobic carbon nanochannels created in the PHBV matrix with the incorporation of the CNFs allowed the degradation medium to penetrate at ultrafast diffusion speed increasing the area exposed to degradation. However, the hydrogen bonds formed between the 2D hydrophilic GO nanosheets and the hydrophobic PHBV polymer chains produced a homogeneous composite structure that exhibits lower degradation (weight loss of ~4.5% w/w after three months in acidic aqueous medium). Moreover, the water molecules present in both degradation media can be linked to the hydroxyl (-OH) and carboxyl (-COOH) groups present on the basal planes and at the edges of the GO nanosheets, reducing their degradation potential.

Zirconia nanofibers-loaded reduced graphene oxide fabrication for specific electrochemical detection of methyl parathion

Yttrium-stabilized zirconia@reduced graphene oxide (YSZ@rGO) nanofibers with uniform porous structure were prepared by electrospinning and thermal reduction process. On this basis, PEDOT/YSZ@rGO electrode was fabricated via the electrodeposition for sensitive detection of methyl parathion (MP). Among this, YSZ exhibited outstanding adsorption, rGO improved electron mobility and PEDOT enhanced electrocatalytic properties. The electrochemical impedance spectroscopy (EIS), square wave voltammetry (SWV) and cyclic voltammetry (CV) demonstrated the successful preparation of the sensor. The pH value of the buffer, the pre-deposition time of the working electrode, and the adsorption time have been optimized. Under the optimum condition, the detection limit of the sensor is 1.57 ng·mL−1 (S/N = 3), and the linear detection ranges from 5 to 4000 ng·mL−1, which is superior to most related electrochemical sensors. Furthermore, the sensor exhibits good anti-interference, reproducibility, stability, and satisfactory recovery in real sample, indicating wide commercial applications in detecting food safety and monitoring wastewater emission.

Fabrication of titanium dioxide/reduced graphene oxide nanofibers for photodegradation of tartrazine dye in aqueous solution

Fabrication of titanium dioxide/reduced graphene oxide nanofibers for photodegradation of tartrazine dye in aqueous solution

The effect of incorporating graphene and polycaprolactone-grafted graphene oxide nanosheets on thermal and physico-mechanical properties, microstructure and biocompatibility of electrospun polyurethane nanocomposite mats

Bead-free electrospun polyurethane/graphene (PU-G) and polyurethane/reduced polycaprolactone-grafted graphene oxide (PU-GPCL) nanofiber mats were prepared for wound dressing application. The facilitated electron signal diffusion throughout the scaffolds boosted the proliferation, cell attachment, and cell viability of the 3T3 fibroblast cells on the PU-G and PU-GPCL nanofiber mats. The partial electrical conductivity induced in PU-G nanocomposites, due to the presence of G nanosheets , reduced the diameters of nanofibers compared to other samples. In addition, the lower tendency of G nanosheets to localize into the nanofibers decreased the mechanical properties of PU-G scaffolds which might restrict their practical applications. On the other hand, the localization of GPCL nanosheets into nanofibers, because of their high affinity with PU matrix, improved the mechanical properties of the PU-GPCL nanofiber mats. Considering the results of different analyses, including mechanical and MTT studies, it could be deduced that PU-GPCL electrospun nanofiber mat containing 1 wt% of GPCL nanosheets could be selected as the potential candidate for wound dressing application. • Bead-less PU/G and PU/GPCL electrospun nanofiber mats were prepared. • SEM images show that GPCL are embedded into the nanofibers due to grafted PCL chains. • MTT assay show cell-interaction of scaffolds with 3T3 fibroblast cells were boosted. • SEM images show PU/G scaffolds have smaller diameters due to electrical conductivity.

The theoretical study of mechanical property and thermostability analysis of poly(vinyl alcohol)/graphene oxide nanofiber composites with different architecture: Molecular dynamics simulation

AbstractIn order to get a deep insight into the correlation between the structure and properties of composite materials, the models of polyvinyl alcohol (PVA)/graphene oxide nanofiber (GOF) composites with different architecture (including random dispersion of GOF in the composites (referred as R‐PVA/GOF composite); columnar cladding of GOF (referred as C‐PVA/GOF composite) and 3D core‐shell structure of GOF (referred as 3D‐PVA/GOF composite) were built, and the mechanical property and thermostability of these composites were analyzed by the molecular dynamic (MD) simulations. It was found that the morphology of GOF in composites had significant influence on its properties. The glass transition temperature (Tg) of C‐PVA/GOF composite was the largest compared to those of other materials (3D‐PVA/GOF composite; R‐PVA/GOF composite and pure PVA). Moreover, the modulus and tensile yield strength of these materials were ordered as follows: C‐PVA/GOF > 3D‐PVA/GOF > R‐PVA/GOF > PVA. The microstructure analysis of materials revealed that the different morphology of GOF affected not only its interactions with PVA but also the ability of components to form hydrogen bonds, the arrangement of PVA molecular chains and the fraction of the free volume in the system, leading to differences in the properties of composites with different structures.

Self‐Assembly of 2D Nanosheets into 1D Nanostructures for Sensing NO2

Ultrathin 2D nanosheets are one of the appealing building blocks for constructing self‐assembled nanostructures. Herein, a facile, fast, and general solvent‐mediated route for the high‐yield and large‐scale self‐assembly of ultrathin 2D nanosheets into 1D nanofibers and nanorings is reported. Solution‐dispersed graphene oxide (GO), MoS2, TiS2, and TaS2 nanofibers with lengths of several tens of micrometers and diameters of 20–50 nm are formed via the self‐assembly of their corresponding single‐layer nanosheets by simply vibrating their tetrahydrofuran suspensions under vortex for 1 min at room temperature. Interestingly, by simply changing the solvent from tetrahydrofuran to acetone, nanorings with diameters of 200–500 nm can be obtained via a similar process. As a proof‐of‐concept application, the reduced GO (rGO) nanofibers obtained by thermal reduction of the GO nanofibers are used as the channel material to fabricate electronic gas sensor, showing good sensitivity (with a detection limit of ≈75 ppb) and selectivity toward NO2. The simple assembly strategy can be used to assemble other ultrathin 2D nanomaterials into 1D nanostructures for various promising applications.

Preparation and characterization of graphene oxide and cellulose nanofibers/ polyvinyl alcohol nanocomposite film

Polyvinyl alcohol (PVA) is well-known in the packaging industry, especially in the food and medical fields with the ability to be completely biodegradable and easily soluble in cold water therefore products made from it are the environmentally friendly materials. However, the disadvantages of this polymer as quick dissolubility in water, poor moisture retention, weak mechanical properties reduce its applications. In this study, PVA, reinforced by “green” components at the nanometer-level such as nanocellulose fibers (CNF), graphene oxide (GO) nanosheets showed improvements in properties. Mechanical properties of all of nanocomposite films showed improvements in stress at break and modulus. Especially, reinforced GO and CNF films increased almost doubled and improved more 40% in modulus than the pure PVA film and films reinforced by only GO or CNF. When immersed in water (neutral pH) at room temperature, graphene oxide-reinforced films not only had effective improvements in swelling time but also supported to decrease water retension of film added CNF. The combined reinforcement also indicated a benefit in reducing the rate of water vapor loss of the film as well as the efficiency in declining the moisture absorption of the nanocomposite films. The PVA films reinforced by nanocellulose fibers and graphene oxide sheets overcomed some of the PVA's shortcomings. This helped expanding its applications in the field of environmentally friendly nanocomposite films.

A Novel Electrochemical Sensor Based on Carbon Dots-Nafion Composite Modified Bismuth Film Electrode for Simultaneous Determination of Cd2+ and Pb2+

Introduction Bismuth film electrodes (BiFEs) have become a hopeful alternative to mercury drop and film electrodes due to its non-toxicity and equal or even superior electrochemical performance towards the heavy-metal-ion determination [1]. Meanwhile, various carbon nanomaterials such as graphene oxide, carbon nanotubes, and carbon nanofibers had been composited with bismuth to further improve the sensitivity and reproducibility of the bismuth-based electrode. In recent years, carbon dots (CDs), as a new carbon nanomaterial, have also been successfully composited with bismuth and applied in photocatalysis[2] and energy storage[3]. However, there have been less previous researches for the enhancement of electrochemical performance of bismuth-based electrodes by CDs. It is reported, CDs may have similarity properties to other carbon nanomaterials such as good electrical conductivity and a large active area, which could be used as modified electrode materials to improve the performance of electrochemical sensors [4]. Therefore, it would be of special interest to fabricate a novel bismuth-based electrode based on CDs for improving the electrode performance of Cd2+ and Pb2+ detection.In this work, CDs, Nafion, and bismuth were deposited onto the GCEs sequentially to form a novel chemical sensor for Cd2+ and Pb2+ ions rapid detection. It is hoping to develop an inexpensive, highly selective, rapid and environmental friendly sensors for Cd2+ and Pb2+ determination in the practical environment and agriculture samples. Methods CDs were prepared with a facile one-pot hydrothermal method using glucose as the carbon source. To fabricate BiF/CDs/Nafion/GCE, the bare GCEs were polished well with a diamond suspension solution for the further modified. Then, the CDs were electrodeposited on the GCE using cyclic voltammetry in H2SO4 solution containing CDs. Finally, 5 μL of 1 wt.% Nafion film was used as an adhesive to stabilize the CDs and improve the reproducibility of the modified electrode. The obtained electrochemical sensor was abbreviated as CDs/Nafion/GCE. For comparison, Nafion/GCE was prepared using a similar method. Bismuth was in situ deposited onto the modified electrode from non-deaerated HAc-NaAc (pH 4.5) buffer solution in the presence of 1000 μg L-1 Bi3+ with model target metals. A conventional three-electrode system was adopted to analyze Cd2+ and Pb2+ concentrations using an Autolab PGSTAT204 workstation (Metrohm). Conclusions Fig. 1 and Table 1 present the DPV electrochemical performance of bare GCE, Nafion/GCE, CDs/Nafion/GCE and BiF/Nafion/GCE in 0.1 M acetate buffer (pH 4.5) containing 0.25 μg mL-1 Cd2+ and Pb2+. The DPV curves of bare GCE and Nafion/GCE both display two weak stripping peaks for Cd2+ and Pb2+, respectively. After modification on the GCE surface with CDs-Nafion film, the stripping peak currents of Cd2+ and Pb2+ significantly increased indicating the CDs may have the ability to spur the electron transfer rate of the detection system [5]. More importantly, BiF/CDs/Nafion/GCE exhibited increased sensitivity for simultaneous detection of Cd2+ and Pb2+ compared with bare GCE and CDs/Nafion/GCE. The Cd2+ current obtained with BiF/CDs/Nafion/GCE was 71.02 and 4.85 times higher than with bare GCE and CDs/Nafion/GCE, respectively. The Pb2+ current obtained with BiF/CDs/Nafion/GCE was 51.85 and 6.31 times higher than what was obtained with bare GCE and CDs/Nafion/GCE, respectively.Fig. 2 and Table 2 show the simultaneous stripping analysis of Cd2+ and Pb2+ using the BiF/CDs/Nafion/GCE. The DPV curves show individual peaks at approximately -0.75 V for Cd2+ and 0.55 V for Pb2+. The separation between two peaks was approximately 200 mV, a difference that is sufficient to detect Cd2+ and Pb2+ simultaneously and selectively. The inset in Fig. 2 presents the linear relationship between the peak currents and the concentrations of Cd2+ and Pb2+. The linear equations are Ip=18.82C+3.49 (R2=0.994) for Cd2+ and Ip=25.12C+3.55 (R2=0.993) for Pb2+. The calculated detection limits (3δ method) for Cd2+ and Pb2+ are 0.003 and 0.002 mg L-1, respectively.The low detection limits suggest that the BiF/CDs/Nafion/GCE is a feasible sensor to simultaneously detect Cd2+ and Pb2+, which has great promise for application in the fields of agricultural and environmental monitoring. Table 1. Electrochemical performance of the bare GCE, Nafion/GCE, CDs/Nafion/GCE and BiF/CDs/Nafion/GCE in detecting Cd2+ and Pb2+. Bare GCE Nafion/GCE CDs/Nafion/GCE BiF/CDs/Nafion/GCE Cd2+ I/μA 0.116 0.045 1.697 8.239 E/V -0.782 -0777 -0.797 -0.772 Pb2+ I/μA 0.192 0.103 1.577 9.957 E/V -0.540 -0.525 -0.565 -0.520 Table 2. The analytical performance of BiF/CDs/Nafion/GCE in the simultaneous detection of Cd2+ and Pb2+. Analytes Linear range (mg L-1) LOD (mg L-1) R2 Simultaneous analysis Cd2+ 0.05 - 0.50 0.003 0.994 Pb2+ 0.05 - 0.50 0.002 0.993 Keywords: Carbon points; Bismuth film; Cadmium; LeadFunding: This work was financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment (Project no. 2018ZX07109003).

Ternary nanocomposites of rGO:RuO2:Pani based flexible electrode for supercapacitor applications

Herein, we fabricated ternary nanocomposites (NCs) of reduced graphene oxide (rGO), ruthenium oxide (RuO2) and polyaniline nanofiber (Pani-NFs) as a flexible electrode for supercapacitor application. NCs and their individual components were characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The ternary NCs displayed areal capacitance as high as 1.5 F .cm−2 and thereby, indicated its potential as a supercapacitor electrode material.

Extraordinary H2S gas sensing performance of ZnO/rGO external and internal heterojunctions

External and internal heterojunctions of reduced graphene oxide (rGO) and ZnO nanofibers (NFs) are developed for ultrasensitive H2S sensing. The gas response of both heterojunctions is significantly higher than that of bare ZnO NFs. The internal heterojunction of 0.1 wt% rGO/ZnO NFs exhibited the highest gas response, reaching 1353–1 ppm H2S at 350 °C and increasing up to 25-fold, compared to bare ZnO NFs. Whereas response of the former to 1000 ppm H2, 1000 ppm NH3, and 1 ppm SO2 gases is negligible (1.5–9). Moreover, the present sensor exhibits an ultralow detection limit of 4.9 ppt and excellent stability towards H2S. A novel sulfuration-desulfuration sensing mechanism is proposed to explain the high response and selectivity to H2S.

Enhanced Optical Sensitivity of Polyvinyl Alcohol–Reduced Graphene Oxide Electrospun Nanofiber Coated Etched Fiber Bragg Grating Sensor for Detection of Myoglobin a Cardiac Biomarker

Etched fiber Bragg grating (eFBG) sensors have shown to be highly sensitive with the capability of giving accurate real‐time response to a variety of measurands such as pressure, gas, biomolecules, to name a few. These sensors have not shown their mettle as competitive products mainly due to nonreproducibility in results and inefficiency in upscaling for large‐scale production; the main reason being nonuniform and complicated coating procedures. Herein, the enhancement in refractive index (RI) sensitivity (≈4 times) obtained with electrospinning of polyvinyl alcohol–reduced graphene oxide (PVA–rGO) nanofibers onto eFBG sensor using a customized target and a unique sandwich arrangement is demonstrated. The enhancement in RI sensitivity has led to a lower detection limit and increased sensitivity and linear range for a case study using myoglobin (Mb), an early‐stage cardiac biomarker with high reproducible results (standard error ≤±2.3%). rGO embedded PVA nanofiber electrospun onto an eFBG sensor (PVA–rGO sensor) is the first of its kind and has significant importance in developing cost‐effective, label‐free, multianalyte, portable, real‐time, point‐of‐care (POC) kits at ambient conditions.

Conductive Biomass Films Containing Graphene Oxide and Cationic Cellulose Nanofibers for Electric-Heating Applications.

A low-voltage biomass matrix and flexible electric-heating composite with graphene oxide (GO) and cationic cellulose nanofiber (CCNF) were fabricated by ultrasonic dispersion and suction filtration. The main results show that the tensile strength and strain of the films decreased with an increase in the GO content, but the thermal stability increased. The GO/CCNF film underwent rapid thermal decomposition at 250–350 °C, and the maximum degradation temperature was higher by 19 °C compared to that of the pure CCNF film. It was found that the electrical conductivity increased from 0.013 to 2.96 S/cm with an increase in the GO content from 20 to 60 wt%, resulting in an increase in the power density from 122 to 2456 W/m2. The films could rapidly attain the temperature within 50 s, and the heat transferred by radiation and convection was 21.62 mW/°C, thereby exhibiting excellent electric heating response. Moreover, the film demonstrated a stable electric-heating cycle after a 12.5 h cycling test and meets the requirements of low-temperature electric heating products under the 36 V electric safety limit, which expands the potential applications of biomass-derived cellulose nanofibers.

Synthesis and Characterization of Tertiary Nanothermite CNMs/Al/KClO4 with Enhanced Combustion Characteristics

AbstractMuch attention has been directed toward the development of new energetic materials to achieve the increasingly demanding performance of high‐speed propulsion systems. Nanothermite is one of the main approaches for the development of new energetic materials by the close integration of oxidizer and metal fuel. This study is devoted to evaluating the impact of different carbon nanomaterials (graphene oxide, reduced graphene oxide, carbon nanotubes, and carbon nanofibers) on the thermal behavior of nanothermites based on potassium perchlorate and nano aluminium powder. Nanothermite compositions were prepared using a conventional sonication method. The morphology of nanothermites was characterized by a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS), which confirmed that the nanoparticles are homogeneously dispersed without agglomeration. The structure of nanothermite was also characterized by Fourier Transform Infrared Spectroscopy (FTIR), X‐ray diffraction (XRD), and Raman spectroscopy. The impact of carbon nanomaterials on the combustion behavior of nanothermite was evaluated by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and bomb calorimetry. There was good agreement between results from DSC and bomb calorimetry. In general, the total heat released improved with the addition of carbon nanomaterials and particularly graphene oxide, which generated the highest increase in the heat of combustion. In addition, the maximum decomposition temperature shifted to a lower temperature, which indicates enhanced ignition characteristics. This is the first time reporting on the synthesis and characterization of tertiary nanothermites based on nano‐aluminum, potassium perchlorate, and carbon nanosize materials. It can be concluded that these novel nanothermite compositions exhibit dramatically improved properties as demonstrated by a 200 % increase in the heat of combustion with only a 5 % addition of graphene oxide. Moreover, the ignition temperature decreased from 545.1 °C to 508.7 °C enhancing the overall combustion characteristics.

Fabrication and Characterization of Polyvinylpyrrolidone-Eggshell Membrane-Reduced Graphene Oxide Nanofibers for Tissue Engineering Applications.

One of the best methods to prevent wound infection and speed up wound healing is wound dressing based on nanofiber–polymer scaffolds, which have acceptable antimicrobial performance and appropriate skin regeneration capabilities. In this paper, the electrospinning method was applied to synthesize the polyvinylpyrrolidone-acrylic acid hydrogel (PVPA)–eggshell membrane (ESM)–reduced graphene oxide (rGO) nanosheets nanocomposite dressings with different reduced graphene oxide contents (0, 0.5, 1, and 2 wt.%). Thus, smooth nanofibers were fabricated, including a high amount of rGO, which reduced the fiber diameter. Based on the results, rGO played an important role in water impermeability. The results showed that by increasing the rGO concentration from 0.5 to 2 wt%, the contact angle value increased persistently. Results showed that compared to PVPA–ESM, the mechanical strength and strain of PVPA–ESM/1 wt% rGO significantly enhanced 28% and 23%, respectively. Incorporation of 1 wt% rGO enhanced swelling ratio from 875% for PVPA-ESM to 1235% after 420 min, while increasing the rGO to 2 wt% increased the degradation rate of the composites. According to the in vitro cell culture studies, PVPA-ESM wound dressings with 0.5–1 wt% rGO content enhanced PC12 cell viability compared to the wound dressings without rGO nanosheets. Generally, rGO–loaded PVPA-ESM nanofiber wound dressing can be considered as a potential candidate to be used in skin regeneration applications.

A Fishing‐Net‐Like 3D Host for Robust and Ultrahigh‐Rate Lithium Metal Anodes

Constructing an architectural host is demonstrated to be an effective strategy for long-life lithium metal anodes (LMAs). Herein, an integrated 3D host for stable and ultrahigh-rate LMAs is developed by a binary highly conductive network of 2D reduced graphene oxide (rGO) and 1D carbon nanofibers (CNF) anchored with 0D ultrasmall MgZnO nanoparticles (MgZnO/CNF-rGO). A facile net-fishing strategy is proposed to combine the rGO nanosheets with free-standing CNF matrix as interconnected paths for fast electron transport. Notably, serving as Li nucleation sites, the superlithiophilic MgZnO nanoparticles are uniformly distributed and tightly contacted with the conductive matrix without agglomeration due to the rGO confinement. Such a delicate nanoscale combination guarantees the effective transportation and uniform deposition of Li-ions in the inner surface of the host. The symmetric cell of Li@MgZnO/CNF-rGO exhibits a long lifespan above 1450 cycles under an ultrahigh current density of 50mAcm-2 with an areal capacity of 1.0mAhcm-2 . Impressively, it also delivers a high reversible capacity of 10mAhcm-2 at 50mAcm-2 . This work offers an avenue to promise the prospect for practical LMAs working under high rates and capacities.