Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g− 1 after 200 cycles at a current density of 200 mA g− 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.

In this work, a nanocomposite containing gold (Au) nanofibers decorated iron-metal–organic framework (Fe-MOF) was successfully synthesized for electrochemical detection of acetaminophen (AAP). The as-synthesized Au@Fe-MOF nanocomposite was confirmed by various characterization techniques. Morphological analysis showed that the Au nanofibers with an average size of less than 10 nm were dispersed on the Fe-MOF. Cyclic voltammetric analysis showed that the Au@Fe-MOF nanocomposite showed well-defined redox peaks with higher current than that of GCE and Fe-MOF. The Au@Fe-MOF/ GCE exhibited a linear range, sensitivity, and detection limit of 0.5–18 μM, 4.95 μM/μA/cm2, and 0.12 μM, respectively. The Au@Fe-MOF/GCE showed a very low response for the interference materials. The real sample analysis revealed that the Au@Fe-MOF/GCE showed good recovery towards the AAP in urine and paracetamol. Therefore, the developed sensor can be used for quality control of AAP.

In this article, nitrogen (N) doped porous carbon nanofibers (N-PCNF) were prepared by carbonization of polymer-silica nanocomposite precursor, and its application for heavy metal ion removal was demonstrated. Carbon–silica composite nanofibers were obtained by carbonization of electrospun polyacrylonitrile (PAN)-silica nanofiber composites. Subsequent selective etching of silica porogen produced porous carbon nanofibers (PCNF). It was revealed by surface characterization with X-ray photoelectron spectroscopy (XPS) that the surface of the PCNF was nitrogen-doped because N atom from cyanide group in PAN chains remained in the hexagonal carbon structure. The use of the obtained N-PCNF for heavy metal ion ( Hg2+) removal was demonstrated using a simple adsorption test apparatus and 5, 10, 15, 20-tetraphenylporphine tetrasulfonic acid (TPPS) as an indicator. The N-PCNF showed a removal efficiency of 96 and 99% in 10 and 120 min, respectively, indicating a maximum heavy metal ion adsorption capacity at pH 7.0. In addition, heavy metal ion adsorption behavior was also analyzed using common adsorption isotherms. This article provides important information for future research activities regarding control over hazardous substances.

Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/ g), large pore volume (0.212 cm3 g− 1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g− 1 with current density of 0.2 A g− 1 and it is maintained to 65.6 F g− 1 at high current density of 2.0 A g− 1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg− 1 at 400 W kg− 1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.

A carbon nanofiber was produced from the Areca catechu husk as a supercapacitor electrode, utilizing a chemical activation of potassium hydroxide (KOH) at different concentrations. One-stage integrated pyrolysis both carbonization and physical activation were employed for directly converting biomass to activated carbon nanofiber. The morphology structure, specific surface area, pore structure characteristic, crystallinity, and surface compound were characterized to evaluate the influence on electrochemical performance. The electrochemical performance of the supercapacitor was measured using cyclic voltammetry (CV) through a symmetrical system in 1 M H2SO4. The results show that the KOH-assisted or absence activation converts activated carbon from aggregate into a unique structure of nanofiber. The optimized carbon nanofiber showed the large specific surface area of 838.64 m2 g−1 with the total pore volume of 0.448 cm3 g−1, for enhancing electrochemical performance. Beneficial form its unique structural advantages, the optimized carbon nanofiber exhibits high electrochemical performance, including a specific capacitance of 181.96 F g−1 and maximum energy density of 25.27 Wh kg−1 for the power density of 91.07 W kg−1. This study examines a facile conventional route for producing carbon nanofiber from biomass Areca catechu husk in economical and efficient for electrode supercapacitor.

Tungsten disulfide (WS2), a typical 2D layerd structure, has received much attention as a pseudocapacitive material because of its high theoretical specific capacity and excellent ion diffusion kinetics. However, WS2 has critical limits such as poor long-term cycling stability owing to its large volume expansion during cycling and low electrical conductivity. Therefore, to increase the high-rate performance and cycling stability for pseudocapacitors, well-dispersed WS2 nanoparticles embedded in carbon nanofibers (WS2-CNFs), including mesopores and S-doping, are prepared by hydrothermal synthesis and sulfurizaiton. These unique nanocomposite electrodes exhibit a high specific capacity (159.6 F g−1 at 10 mV s−1), excellent high-rate performance (81.3 F g−1 at 300 mV s−1), and long-term cycling stability (55.9% after 1,000 cycles at 100 mV s−1). The increased specific capacity is attributed to well-dispersed WS2 nanoparticles embedded in CNFs that the enlarge active area; the increased high-rate performance is contributed by reduced ion diffusion pathway due to mesoporous CNFs and improved electrical conductivity due to S-doped CNFs; the long-term cycling stability is attributed to the CNFs matrix including WS2 nanoparticles, which effectively prevent large volume expansion.

To improve the performance of carbon nanofibers as electrode material in electrical double-layer capacitors (EDLCs), we prepare three types of samples with different pore control by electrospinning. The speciments display different surface structures, melting behavior, and electrochemical performance according to the process. Carbon nanofibers with two complex treatment processes show improved performance over the other samples. The mesoporous carbon nanofibers (sample C), which have the optimal conditions, have a high sepecific surface area of 696 m2 g−1, a high average pore diameter of 6.28 nm, and a high mesopore volume ratio of 87.1%. In addition, the electrochemical properties have a high specific capacitance of 110.1 F g−1 at a current density of 0.1 A g−1 and an excellent cycling stability of 84.8% after 3,000 cycles at a current density of 0.1 A g−1. Thus, we explain the improved electrochemical performance by the higher reaction area due to an increased surface area and a faster diffusion path due to the increased volume fraction of the mesopores. Consequently, the mesoporous carbon nanofibers are demonstrated to be a very promising material for use as electrode materials of high-performance EDLCs.

Mesoporous carbon nanofibers as electrode material for electrical double-layer capacitors(EDLCs) are fabricated using the electrospinning method and carbonization. Their morphologies, structures, chemical bonding states, porous structure, and electrochemical performance are investigated. The optimized mesoporous carbon nanofiber has a high sepecific surface area of 667 m2 g−1, high average pore size of 6.3 nm, and high mesopore volume fraction of 80 %, as well as a unifom network structure consiting of a 1-D nanofiber stucture. The optimized mesoporous carbon nanofiber shows outstanding electrochemical performance with high specific capacitance of 87 F g−1 at a current density of 0.1 A g−1, high-rate performance (72 F g−1 at a current density of 20.0 A g−1), and good cycling stability (92 F g−1 after 100 cycles). The improvement of the electrochemical performance via the combined effects of high specific surface area are due to the high mesopore volume fraction of the carbon nanofibers.

In this study, composite PAN-based ACNFs embedded with MgO and MnO2 were prepared by the electrospinning method. The resultant pristine ACNFs, ACNF/MgO and ACNF/MnO2 were characterized in terms of their morphological changes, SSA, crystallinity and functional group with FESEM-EDX, the BET method, XRD and FTIR analysis, respectively. Results from this study showed that the SSA of the ACNF/MgO composite (1893 m2 g–1) is significantly higher than that of the pristine ACNFs and ACNF/MnO2 which is 478 and 430 m2 g–1, respectively. FTIR analysis showed peaks of 476 and 547 cm–1, indicating the presence of MgO and MnO2, respectively. The FESEM micrographs analysis showed a smooth but coarser structure in all the ACNFs. Meanwhile, the ACNF/MgO has the smallest fiber diameter (314.38±62.42 nm) compared to other ACNFs. The presence of MgO and MnO2 inside the ACNFs was also confirmed with EDX analysis as well as XRD. The adsorption capacities of each ACNF toward CH4 were tested with the volumetric adsorption method in which the ACNF/MgO exhibited the highest CH4 adsorption up to 2.39 mmol g–1. Meanwhile, all the ACNF samples followed the pseudo-second order kinetic model with a R2 up to 0.9996.

Polyacrylonitrile/pitch nanofibers were prepared by electrospinning as a precursor for a gas sensor material. Pitch nanofibers were properly fabricated by incorporating polyacrylonitrile as an electrospinning supplement component. Polyacrylonitrile/pitch nanofibers were activated with steam at various temperatures followed by subsequent carbonization to make carbon nanofibers with a highly conductive graphitic structure. Steam activation was effective in facilitating gas adsorption onto the carbon nanofibers due to the increased surface area. The carbon nanofibers activated at 800°C had a larger surface area and a lower micro pore fraction resulting in a higher variation in electrical resistance for improved CO gas sensing properties.

고강도, 내약품성, 무독성, 내연소성의 장점을 가지고 있는 PVdF (polyvinylidene fluoride) 나노섬유로 기공이 0.4 μm 평막을 제조한 후, 부직포와 평막으로 나권형 모듈을 제작하였다. 용존유기물의 흡착 제거를 위한 입상 활성탄(GAC, granular activated carbon) 흡착 컬럼과 자체 제작한 나권형 모듈로 혼성 수처리 공정을 구성하였다. 카올린과 휴믹산으로 조 제한 모사 용액을 대상으로, 처리수를 재순환하는 경우와 배출하는 경우 각각 GAC 충진량의 영향을 알아보았다. 여과실험 후 물 역세를 하여 회복률과 여과저항을 계산하였다. 또한, 탁도와 UV254 흡광도를 측정하여 GAC의 흡착 효과를 고찰하였 다. 그 결과, 처리수를 재순환하는 경우와 배출하는 경우 모두 탁도 처리율에는 GAC 충진량의 영향이 없었다, 하지만 GAC 의 UV254 흡광도 처리율이 처리수를 순환하는 경우 0.7~3.6%이었는데, 처리수를 배출하는 경우 3.2-5.7%로 증가하였다. 처리 수를 순환하는 경우 GAC의 충진량이 증가함에 따라, 가역적 여과저항(Rr)과 비가역적 여과저항(Rir)은 감소하는 경향을 보였 다. 그러나 총여과저항(Rt)은 거의 일정하였고, 물 역세 회복률(Rb)은 다소 증가하는 경향을 보였다.

Nanofibers(NFs), because of their high surface area and nanosized grains, have appropriate morphologies for use in chemiresistive-type sensors for gas detection applications. In this study, a highly sensitive and selective CO gas sensing material based on Au-decorated SnO2 NFs was fabricated by electrospinning. SnO2 NFs were synthesized by electrospinning and subsequently decorated with various amounts of Au nanoparticles(NPs) by sputtering; this was followed by thermal annealing. Different characterizations showed the successful formation of Au-decorated SnO2 NFs. Gas sensing tests were performed on the fabricated sensors, which showed bell-shaped sensing behavior with respect to the amount of Au decoration. The best CO sensing performance, with a response of ~20 for 10 ppm CO, was obtained at an optimized amount of Au (2.6 at.%). The interplay between Au and SnO2 in terms of the electronic and chemical sensitization by Au NPs is responsible for the great improvement in the CO sensing capability of pure SnO2 NFs, suggesting that Au-decorated SnO2 NFs can be a promising material for fabricating highly sensitive and selective chemiresistive-type CO gas sensors.

N-doped carbon nanofibers as catalysts for oxygen-reduction reactions are synthesized using electrospinning and carbonization. Their morphologies, structures, chemical bonding states, and electrochemical performance are characterized. The optimized N-doped carbon nanofibers exhibit graphitization of carbon nanofibers and an increased nitrogen doping as well as a uniform network structure. In particular, the optimized N-doped carbon nanofibers show outstanding catalytic activity for oxygen-reduction reactions, such as a half-wave potential (E1/2) of 0.43 V, kinetic limiting current density of 6.2 mA cm-2, electron reduction pathways (n = 3.1), and excellent long-term stability after 2000 cycles, resulting in a lower E1/2 potential degradation of 13 mV. The improvement in the electrochemical performance results from the synergistic effect of the graphitization of carbon nanofibers and the increased amount of nitrogen doping.

Co-embedded graphitic porous carbon nanofibers(Co-GPCNFs) are synthesized by using an electrospinning method. Their morphological, structural, electrochemical, and photovoltaic properties are investigated. To obtain the optimum condition of Co-GPCNFs for dye-sensitized solar cells(DSSCs), the amount of cobalt precursor in an electrospinning solutuion are controlled to be 0 wt%(conventional CNFs), 1 wt%(sample A), and 3 wt%(sample B). Among them, sample B exhibited a high degree of graphitization and porous structure compared to conventional CNFs and sample A, which result in the performance improvement of DSSCs. Therefore, sample B showed a high current density(JSC, 12.88 mA/cm2) and excellent power conversion efficiency(PCE, 5.33 %) than those of conventional CNFs(12.00 mA/cm2, 3.78 %). This result can be explained by combined effects of the increased contact area between the electrode and elecytolyte caused by improved porosity and the increased conductivity caused by the formation of a high degree of graphitization. Thus, the Co-GPCNFs may be used as a promising alternative of Pt-free counter electrode in DSSCs.

기공 0.4 μm PVDF 나노섬유 정밀여과 나권형 모듈과 GAC 컬럼의 혼성공정에서 모사용액을 순환 없이 선형유속 0.013 m/s, TMP를 0.5 bar 조건으로 GAC 충진량을 변화시키면서 실험하였다. 또한 동일한 혼성공정에서 모사용액을 순환시키면서 선형유속 0.026 m/s, TMP 1.5 bar의 조건으로 GAC 충진량의 영향을 고찰하였다. 탁도와 UV254 흡광도(DOM) 처리율을 비교하였는데, 탁도 처리율에는 영향이 없었으나, GAC의 충진량이 많을수록 DOM 이 증가하였다. 하지만 TMP와 유속이 높은 조건인 순환이 있는 실험에서 GAC에 의한 DOM 처리율이 더 낮은 이유는 순환으로 인해 모사용액 농도가 낮아졌기 때문인 것으로 판단된다.

강도가 강하고 내약품성, 무독성, 내연소성의 장점을 가지고 있는 PVdF (polyvinylidene fluoride) 나노섬유로 기공이 0.4 μm 평막을 제조한 후, 그 평막으로 부직포를 첨가하여 나권형 모듈을 제작하였다. 카올린과 휴믹산으로 조제한 모사용액과 순수를 대상으로 나권형 모듈의 투과선속과 처리율을 비교하여 pH의 영향을 알아보았고, 여과실험 후 물 역세척을 하여 회복률과 여과저항을 계산하였다. 또한, 나권형 모듈을 통과한 처리수를 입상 활성탄(GAC, granular activated carbon)으로 채워진 컬럼에 통과시킨 후, 탁도와 UV254 흡광도를 측정하여 GAC의 흡착 효과를 고찰하였다.

New precursors, poly(acrylonitrile-co-crotonic acid) (poly(AN-CA)) and poly(acrylonitrile-co-itaconic acid-co-crotonic acid) (poly(AN-IA-CA)) copolymers, for the preparation of carbon fibers, were explored in this study. The effects of comonomers with acidic groups, such as crotonic acid (CA) and/or itaconic acid (IA), on the stabilization of nanofibrous polyacrylonitrile (PAN) copolymers were studied. The extent of stabilization, evaluated by Fourier transform infrared spectroscopy, revealed that the CA comonomer could retard/control the stabilization rate of PAN, in contrast to the IA comonomer, which accelerated the stabilization process. Moreover, the synthesized PAN copolymers containing CA possessed higher Mv than those of the IA copolymers and also showed outstanding dimension stability of nanofibers during the stabilization, which may be a useful property for improving the dimensional stability of polymer composites during manufacturing.