PAN-based Carbon Nanofibers Research Articles

Electrochemical evaluation of ZnO and PAN-based carbon nanofibers composite for high-performance supercapacitor application

Electrochemical evaluation of ZnO and PAN-based carbon nanofibers composite for high-performance supercapacitor application

Effect of terephthalic acid addition on the stabilization, nanostructural and electrochemical performance of PAN based carbon nanofibers film

Effect of terephthalic acid addition on the stabilization, nanostructural and electrochemical performance of PAN based carbon nanofibers film

Hollow Co/CoO/Carbon nanofibers promoted PMS decomposition for the degradation of Rhodamine B

Carbon nanofibers with hollow structures have an excellent application prospect in various fields because of their high specific surface area and abundant active sites. PAN-based hollow carbon nanofiber doped with Co/CoO (H–Co/CoO–CNF) was successfully prepared and used as a catalyst to activate peroxymonosulfate (PMS) and degrade Rhodamine B (RhB). The catalyst showed a surprising degradation rate (98.89%) of RhB within 15 min and had good degradation performance in a wide pH range (pH 1.5–11.2). Compared with solid fibers, H–Co/CoO–CNF shows better cyclic characteristics. The catalyst is also magnetic and recoverable easily due to the addition of Co/CoO. Two pathways of both radical (SO4•−) and non-radical (1O2) exist during the RhB degradation process are confirmed through electron paramagnetic resonance (EPR) analysis and radical quenching experiments. This work provides a new idea for hollow fibers loaded with metals and their oxides and can guide the development of catalysts for advanced oxidation processes in the future.

Insight into the molecular structure of coal liquefaction residue fractions for optimizing the electrochemical performance of PAN based carbon nanofiber nonwovens

The organic fractions in coal liquefaction residue, such as asphaltene (CLRA) and preasphaltene (CLRPA), are the preferred precursors for preparing carbon materials as electrodes in supercapacitors (SCs) and lithium-ion batteries (LIBs). The molecular structure, size and the corresponding carbonized products of CLRA and CLRPA are characterized by Fourier-transform infrared, Nuclear magnetic resonance and Raman spectroscopies, in addition to X-ray diffractometry. The effects of CLRA and CLRPA on the properties and electrochemical performance of polyacrylonitrile based carbon nanofiber nonwovens (PANCF) are investigated. For SCs, the CLRA based carbon nanofiber nonwoven shows a satisfactory specific capacitance of 221 F g-1 at 1 A g-1 and an outstanding rate capability of 79 % from 1 to 100 A g-1. For LIBs, this material also has an excellent reversible specific capacity of 251 mAh g-1 at 0.2 A g-1 after 600 cycles. Moreover, the free-standing electrodes for SCs and LIBs not only essentially reduce the complexity of the electrodes preparation process and enhance the utilization of the active materials.

Excellent microwave absorption of lightweight PAN-based carbon nanofibers prepared by electrospinning

One-dimensional PAN-based carbon nanofibers were prepared by electrospinning in combination with a high-temperature carbonization process. The prepared PAN-based nanofibers were characterized by a high aspect ratio. The microwave absorption property was adjusted by controlling the carbonization temperature. The carbonization temperature affected the degree of graphitization, which directly affected the dielectric loss and further improved the microwave absorption properties of PAN-based carbon nanofibers. The PAN-based carbon fibers were optimized in terms of both maximum reflection loss (RLmin) and effective absorption bandwidth (EAB) after carbonization at 800 °C. The PAN-based carbon fiber/paraffin composites containing 10 wt% filler exhibited excellent absorption performance with a maximum reflection loss of − 12.75 dB and an effective absorption bandwidth of 4.88 GHz (13.12–18 GHz) at 2.2 mm, which basically covered the Ku-band (12.88–17.88 GHz). When the absorber thickness was 2.4 mm, the reflection loss at 14.4 GHz was − 11.39 dB, and the maximum effective absorption bandwidth was 5.04 GHz (11.92–16.96 GHz). PAN-based carbon nanofibers showed excellent absorption properties due to the dielectric loss in cooperation with good impedance matching.

An ultra-wide sensing range film strain sensor based on a branch-shaped PAN-based carbon nanofiber and carbon black synergistic conductive network for human motion detection and human–machine interfaces

A film sensor decorated with branch-shaped carbon nanofibers possessing extra branches achieves high sensitivity, good linearity, a wide sensing range, a fast response time, and great durability.

Catalytic oxidation of NO at low concentrations by carbon nanofibers near room temperature

Polyacrylonitrile (PAN) nanofibers obtained by electrospinning were used to prepare PAN-based carbon nanofibers (PCNFs) by pre-oxidation, carbonization and high-temperature treatment in NH3. The PCNFs were used for the removal of low concentrations of NO (5×10−5) near room temperature (20 °C) by catalytic oxidation. Results indicated that the PCNFs had high porosity and a large specific surface area, and their diameters could be regulated by changing the PAN concentration. The smaller the diameter of the PCNFs the more micropores were developed, and the larger the specific surface area the better the adsorption and catalytic oxidation performance.

Engineered NiCo-LDH nanosheets- and ZnFe2O4 nanocubes-decorated carbon nanofiber bonded mats for high-rate asymmetric supercapacitors

In this work, we have prepared the hierarchically nanostructured core–shell NiCo layered double hydroxide (NiCo-LDH) nanosheets- and ZnFe2O4 nanocubes-decorated polyacrylonitrile (PAN)/pitch-based carbon nanofibers (PPCNs) webs (NiCo-LDH@PPCNs as cathode and ZnFe2O4@PPCNs as anode materials) with the bonded network structure by a facile and scalable hydrothemal method. Herein, the low-cost pitch with lower softening point (∼90 °C) as co-precursor was utilized to produce the PAN/pitch-based carbon nanofibers (PPCNs) with enhanced electrical conductivity. The obtained PPCNs with pitch content of 30% (PP30CNs) electrode material delivered higher specific capacitance (∼67 F g−1) than that (∼48 F g−1) of the PAN-based carbon nanofibers (PCNs) at 1 A g−1, due to the increased electrical conductivity and lower interfacial charge transfer resistance (RCT) of ∼0.16 Ω. Further, the NiCo-LDH-decorated PP30CNs (NiCo-LDH@PP30CNs) as cathode material showed superior specific capacitance of 1162 F g−1 at 1.0 A g−1 and ultra-high retention rate of 91.56% at 10 A g−1. The ZnFe2O4@PP30CNs as anode material also showed higher specific capacitance of 282 F g−1 at 1 A g−1 and good rate capability with capacitance retention of 56.73% at 10 A g−1. The as-fabricated asymmetric NiCo-LDH@PP30CNs//ZnFe2O4@PP30CNs hybrid supercapacitor device delivered a specific capacitance of ∼98 F g−1 at 1 A g−1 and excellent capacitance retention of ∼88% after 5000 charge–discharge cycles.

Main structural and mechanical properties of electrospun PAN-based carbon nanofibers as a function of carbonization maximum temperature

In this study, PAN-based carbon nanofibers (CNFs) were synthesized via electrospinning followed by stabilizing and carbonization. The carbonization process was performed by heating the fibrous mats up to a maximum temperature in the region of 800–1600 °C. The effect of carbonization maximal temperature on the structure and tensile strength of carbon nanofiber mats was investigated via SEM, elemental analysis, X-ray diffraction, Raman spectroscopy and tensile testing. Polyacrylonitrile (PAN) concentrations of 6–10% (w/w) and voltages of 14–16 kV were recognized as the optimal electrospinning parameters in order to synthesize of nanofibrous mats without any agglomerated nanoparticles or beads in the mats structure. It is clear from the results that carbon content, crystalline stacking size (Lc), in-plane crystallite size (La) and the number of graphene layers in single crystallite continuously increased with rising carbonization maximum temperature from 800 to 1600 °C, while interlayer d-spacing (d002) decreased at the maximum temperatures of 1000–1400 °C, firstly. This value increased again at the maximum temperatures above1400 °C due to the formation of considerable shrinkages and pores in the CNFs structure. The highest value of tensile strength (206–223 MPa) was recorded for the CNFs mats carbonized up to 1200–1400 °C.

Polyacrylonitrile-Based Nitrogen-Doped Carbon Materials with Different Micro-morphology Prepared by Electrostatic Field for Supercapacitors

Polyacrylonitrile (PAN)-based nitrogen-doped carbon materials with microspherical and nanofibrous morphology were fabricated by using electrostatic technology and carbonization processes. The microscopic morphology of the PAN-based nitrogen-doped carbon precursor materials can be effectively controlled by simply changing the concentration of the PAN solution. When the concentration of the PAN solution was less than 6%, the morphology of the PAN-based carbon precursor material changed from nanofiber to microsphere. The morphology of the precursor material during carbonization had a significant effect on the pore size distribution of the PAN-based nitrogen-doped carbon materials. Therefore, the electrochemical properties of the PAN-based nitrogen-doped carbon nanofibers differed considerably from those of the counterpart microspheres. The electrochemical performance of the PNCF-6 was far superior to those of PNCS-1 and PNCS-4. At a relatively low power density of about 62.4 W kg−1, the PNCF-6 showed the largest energy density (5.4 Wh kg−1).

Rapid adsorption of lead ions using porous carbon nanofibers

Lead is one of the toxic elements in the environment having non-biodegradable behavior. On the other hand, the high contamination of lead in water is a major alarming threat to the world nowadays. In this study, PAN-based porous carbon nanofibers (p-CNFs) were used to adsorb the lead ions for both batch and continuous method. The synthesis was achieved by electrospinning and thermal treatment. The characterization of p-CNFs was achieved via FE-SEM, EDX, BET and Raman spectra. Furthermore, the adsorption capability for lead ions was examined using ICP-MS. The adsorption parameters such as pH of the solution, the mass of nanofibers, adsorption time and initial concentration of lead ions were optimized. The obtained results fitted well with the Langmuir model and the pseudo-second-order model. The nanofibers showed high adsorption capability at neutral pH within 1 min. Therefore, the prepared p-CNFs can be recommended for lead ions removal up to its permissible limit in a continuous purification system for drinking water.

In-built fabrication of MOF assimilated B/N co-doped 3D porous carbon nanofiber network as a binder-free electrode for supercapacitors

Polyacrylonitrile (PAN) based carbon nanofibers (CNFs) show enormous potential as a high performance and cost-effective supercapacitor electrode material. However, there are two intrinsic limitations that prevent their deployment in this field, namely their low surface area and limited transporting channels for ion diffusion. Here, we design an approach that concurrently addresses both problems. We employ electrospinning of PAN and zeolitic imidazolate framework (ZIF-8) nanoparticles to fabricate highly porous CNFs, followed by a sodium borohydride treatment and freeze-drying to maintain the three-dimensionalities of carbon nanofibers networks. Nitrogen and boron co-doping could be achieved together by controlling the conditions for stabilization and carbonization after the ammonium borate tri-hydrate treatment. The novel ZIF-8 incorporated 3D nitrogen and boron co-doped carbon nanofiber electrode was tested as a binder-free supercapacitor electrode and delivered a high specific capacitance of 295 F g−1 at a 0.5 A g−1 current density, exceeding that of PAN-based carbon nanofiber supercapacitor electrodes. Indeed, the novel electrode also maintained a high rate capability and remarkable cyclic stability of 94.5% capacitance retention even after 10 000 charge-discharge cycles. This superior electrochemical performance is attributed to the large surface area, mesoporous nature and high wettability of the B and N doped carbon nanofiber electrode. This study will inspire the development of new 3D PAN and metal organic framework based porous electrode materials for high performance energy storage devices.

Acid-functionalized carbon nanofibers for high stability, thermoelectrical and electrochemical properties of nanofluids

Carbon-based nanofluids are viewed as promising thermal fluids for heat transfer applications. However, other properties, such as electrical conductivity and electrochemical behavior, are usually overlooked and rarely investigated despite their importance for the overall performance characterization of a given application. In this study, we synthesized PAN-based carbon nanofibers (CNF) by electrospinning, and characterized them using electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric analysis. Thermoelectrical and electrochemical measurements were carried out on nanofluids. We found that, although CNF nanofluids exhibit good thermal and electrical properties with a negligible corrosive effect, the suspensions tend to sediment within a few days. However, acid treatment of CNF (F-CNF), which resulted in the shortening of the fibers and the appearance of surface-oxygenated species, made F-CNF-based nanofluids exhibit superior stability in water that extended for more than 90 days, with consistent and superior thermal and electrical properties.

Highly anisotropic electric conductivity in PAN-based carbon nanofibers

In addition to the chemical and physical properties of nanostructures their successful utilization for applications is strongly triggered by economic aspects. Electrospinning of nanowires from solution followed by subsequent annealing steps is a comparably cheap technique to fabricate conductive carbon nanofibers (CNF) made from polyacrylonitrile (PAN) molecules in large quantities. In this work, we investigated the microscopic properties of the CNFs with diameters of 100–300 nm by means of Raman and x-ray photoelectron spectroscopy and correlated these results with transport measurements done with a 4-tip STM. In particular, we investigated the effect of fiber alignment and knot densities, which can be controlled by applying constant creep due to stress during the stabilization process. The comparison of the conductivity obtained from single CNFs revealed further that the fiber crossings within the ensemble structure act as scattering centers and proofs that the transport is along the surfaces of the CNFs.

Electron-spun 2D MoS2-decorated carbon nanofibers as pseudocapacitive electrode material into lithium ion battery

High lithium storage capacity and high conductivity of the LIB anode materials are extremely desirable for lithium-ion batteries (LIBs). Herein, the article demonstrated the method of embedding single or few layers 2D MoS2 into e-spun carbon nanofibers (MS-CNFs) to improve the electrochemical behavior of lithium anode materials. As demonstrated by various microscopic and spectroscopic analyses, MS-CNFs exhibited well-aligned morphology with uniform diameter of 330–360 nm. The roughness surface of MS-CNFs is favorable to shorten ion diffusion pathway and decrease the charge transfer resistance. Moreover, MS-CNFs hybrids exhibit a higher specific capacity of 1172 mAh g−1 with the good rate capability (97.3%) and cycle stability (86.4%) than pristine PAN based carbon nanofibers (p-CNFs) and 2D MoS2 due to the synergistic effect of pseudocapacitive material MoS2 and roughness morphology of CNFs. It is anticipated to exploit surface modification of MoS2 nanosheets and MoS2-based composites with high performances.

Catalytic oxidation of NO by g-C3N4-assisted electrospun porous carbon nanofibers at room temperature: Structure-activity relationship and mechanism study

Here we prepared a novel PAN-based carbon nanofibers (PCNFs) by electrospinning using g-C3N4 as a sacrificial template for oxidizing NO to NO2 at room temperature. The results show that g-C3N4 modified PCNFs can reach a steady conversion of 47.6%, which is much higher than that of PCNFs (23.6%). It is proposed that the g-C3N4 induces some physicolchemical changes that can be responsible for the excellent catalytic performance.

Effective parameters on conductivity of mineralized carbon nanofibers: an investigation using artificial neural networks

The aim of this study was to predict the effects of different parameters on the conductivity of mineralized PAN-based carbon nanofibers by the artificial neural network (ANN) method.

Thermal-based regulation on biomineralization and biological properties of bioglass nanoparticles decorated PAN-based carbon nanofibers

The mechanism and model for biomineralization behavior and cell culture of CNF/BG sintered at various temperatures.

Functionalization of PAN-Based Electrospun Carbon Nanofibers by Acid Oxidation: Study of Structural,Electrical and Mechanical Properties

Electrospun carbon nanofibers (ECNFs) have many qualities that make them attractive for applications in various fields of technology. For many applications, it is necessary to modify the surface of CNFs by chemical functionalization. Here, a systematic functionalization of polyacrylonitrile (PAN)-based ECNFs by oxidation in concentrated nitric acid was examined. The effects of oxidation on the microstructural, electrical, and mechanical characteristics have been studied. The Fourier transform infrared spectroscopy results revealed the time-dependent functionalization of ECNFs. However, according to the scanning electron microscopy, there was no considerable change in the surface morphology of CNFs due to functionalization. The microstructures as well as electrical and mechanical properties were severely dependent on oxidation duration according to X-ray diffraction and Raman spectroscopies as well as conductivity and mechanical strength measurements, respectively. Increase in oxidation duration led to more structural disorders and noticeable decrease in electrical conductivity and mechanical strength.

Preparation of Hollow/Porous Carbon Nanofibers from PAN with High Molecular Weight

In this paper, the hollow or porous carbon nanofibers based on the PAN with high molecular weight were manufactured through concentric electrospinning. The PAN terpolymers with the viscosity-average molecular weight of 30 kDa were synthesized via aqueous precipitation polymerization. Then the prepared PAN was dissolved in DMF to afford the shell. Two kinds of solutions, silicone oil and the 10% PVP DMF solution, were used as the core. After the concentric electrospinning, the obtained core-shell PAN nanofibers exhibit the different morphology. Compared with the 10% PVP DMF solution as the core, the silicone oil as the core led to the greater and more uneven in diameter. After the oxidative stabilization and carbonization, the PAN based carbon nanofibers (CNFs) showed the obvious hollow cores no matter the silicone oil or 10% PVP DMF solution is in core. When the silicone oil is in core, the profiles of the PAN based CNFs reveal the better fibrous shape and thinner diameter. Furthermore, a mixture of PAN and PMMA with the molecular ratio of 1:1 in shell and the 10% PVP DMF solution in core were also concentrically electrospun. FESEM reveals that the addition of PMMA made the nanofibers more even and thinner diameters. After carbonization, the resulted PAN based CNFs show the porous cross-section.