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.

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.

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.

Well-distributed ruthenium (Ru) nanoparticles decorated on porous carbon nanofibers (CNFs) were synthesized using an electrospinning method and a reduction method for use in high-performance elctrochemical capacitors. The formation mechanisms including structural, morphological, and chemical bonding properties are demonstrated by means of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To investigate the optimum amount of the Ru nanoparticles decorated on the porous CNFs, we controlled three different weight ratios (0 wt%, 20 wt%, and 40 wt%) of the Ru nanoparticles on the porous CNFs. For the case of 20 wt% Ru nanoparticles decorated on the porous CNFs, TEM results indicate that the Ru nanoparticles with ~2-4 nm size are uniformly distributed on the porous CNFs. In addition, 40 wt% Ru nanoparticles decorated on the porous CNFs exhibit agglomerated Ru nanoparticles, which causes low performance of electrodes in electrochemical capacitors. Thus, proper distribution of 20 wt% Ru nanoparticles decorated on the porous CNFs presents superior specific capacitance (~280.5 F/g at 10 mV/s) as compared to the 40 wt% Ru nanoparticles decorated on the porous CNFs and the only porous CNFs. This enhancement can be attributed to the synergistic effects of well-distributed Ru nanoparticles and porous CNF supports having high surface area.

Carbon nanofibers (CNFs) with diameters in the submicron and nanometer range exhibit high specific surface area, hierarchically porous structure, flexibility, and super strength which allow them to be used in the electrode materials of energy storage devices, and as hybrid-type filler in carbon fiber reinforced plastics and bone tissue scaffold. Unlike catalytic synthesis and other methods, electrospinning of various polymeric precursors followed by stabilization and carbonization has become a straightforward and convenient way to fabricate continuous CNFs. This paper is a comprehensive and brief review on the latest advances made in the development of electrospun CNFs with major focus on the promising applications accomplished by appropriately regulating the microstructural, mechanical, and electrical properties of as-spun CNFs. Additionally, the article describes the various strategies to make a variety of carbon CNFs for energy conversion and storage, catalysis, sensor, adsorption/separation, and biomedical applications. It is envisioned that electrospun CNFs will be the key materials of green science and technology through close collaborations with carbon fibers and carbon nanotubes.

In this study, activated carbons nanofibers (ACNFs) were prepared from polyacrylonitrile-based nanofibers by physical (H2O and CO2) and chemical (KOH) activation. The surface and structural characteristics of the porous carbon were observed by scanning electron microscopy and X-ray diffraction, respectively. Pore characteristics were investigated by N2/77K adsorption isotherms. The specific surface area of the physically ACNFs was increased up to 2400m2/g and the ACNFs were found to be mainly composed of micropore structures. Chemical activation using KOH produced ACNFs with high specific surface area (up to 2500m2/g), and the micropores were mainly found in the ACNFs. The physically and chemically ACNFs showed both mainly type I from the International Union of Pure and Applied Chemistry classification.

In this study, porous electrospun carbon fibers were prepared by electrospinning with PAN and MgCl2, as a MgO precursor. MgO was selected as a substrate because of its chemical and thermal stability, no reaction with carbon, and ease of removal after carbonization by dissolving out in acidic solutions. MgCl2 was mixed with polyacrylonitrile (PAN) solution as a precursor of MgO with various weight ratios of MgCl2/PAN. The average diameter of porous electrospun carbon fibers increased from 1.3 to 3 μm, as the MgCl2 to PAN weight ratio increased. During the stabilization step, MgCl2 was hydrolyzed to MgOHCl by heat treatment. At elevated temperature of 823 K for carbonization step, MgOHCl was decomposed to MgO. Specific surface area and pore structure of prepared electrospun carbon fibers were decided by weight ratio of MgCl2/PAN. The amount of hydrogen storage increased with increase of specific surface area and micropore volume of prepared electrospun carbon fibers.