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Early detection of histamine in foodstuffs/beverages could be useful in preventing various diseases. In this work, we have prepared a free-standing hybrid mat based on manganese cobalt (2-methylimodazole)–metal organic frameworks (Mn-Co(2-MeIm)MOF) and carbon nanofibers (CNFs) and explored as a non-enzymatic electrochemical sensor for determining the freshness of fish and bananas based on histamine estimation. As-developed hybrid mat possesses high porosity with a large specific surface area and excellent hydrophilicity those allow easy access of analyte molecules to the redox-active metal sites of MOF. Furthermore, the multiple functional groups of the MOF matrix can act as active adsorption sites for catalysis. The Mn-Co(2-MeIm)MOF@CNF mat-modified GC electrode demonstrated excellent electrocatalytic activities toward the oxidation of histamine under acidic conditions (pH = 5.0) with a faster electron transfer kinetics and superior fouling resistance. The Co(2-MeIm)MOF@CNF/GCE sensor exhibited a wide linear range from 10 to 1500 µM with a low limit of detection (LOD) of 89.6 nM and a high sensitivity of 107.3 µA mM −1  cm −2 . Importantly, as-developed Nb(BTC)MOF@CNF/GCE sensor is enabled to detect histamine in fish and banana samples stored for different periods of time, which thus indicates its practical viability as analytical histamine detector.

This book covers the fundamentals and applications of Carbon Nanofiber (CNF).In the first section, the initial chapter on the fundamentals of CNF is by Professor Maheshwar Sharon, the recognized \"Father of Carbon Nanotechnology in India\", which powerfully provides a succinct overview of CNFs.

Developing high‐performance, low‐cost, and robust bifunctional electrocatalysts for overall water splitting is extremely indispensable and challenging. It is a promising strategy to couple highly active precious metals with transition metals as efficient electrocatalysts, which can not only effectively reduce the cost of the preparation procedure, but also greatly improve the performance of catalysts through a synergistic effect. Herein, Ru and Ni nanoparticles embedded within nitrogen‐doped carbon nanofibers (RuNi‐NCNFs) are synthesized via a simple electrospinning technology with a subsequent carbonization process. The as‐formed RuNi‐NCNFs represent excellent Pt‐like electrocatalytic activity for the hydrogen evolution reaction (HER) in both alkaline and acidic conditions. Furthermore, the RuNi‐NCNFs also exhibit an outstanding oxygen evolution reaction (OER) activity with an overpotential of 290 mV to achieve a current density of 10 mA cm−2 in alkaline electrolyte. Strikingly, owing to both the HER and OER performance, an electrolyzer with RuNi‐NCNFs as both the anode and cathode catalysts requires only a cell voltage of 1.564 V to drive a current density of 10 mA cm−2 in an alkaline medium, which is lower than the benchmark of Pt/C||RuO2 electrodes. This study opens a novel avenue toward the exploration of high efficient but low‐cost electrocatalysts for overall water splitting. A facile strategy based on electrospinning and a postcarbonization process is demonstrated to prepare carbon nanofibers incorporating Ru and Ni nanoparticles, which exhibits admirable Pt‐like hydrogen evolution reaction activity and superior oxygen evolution reaction performance. The electrolyzer with this hybrid as both anode and cathode displays a remarkable electrocatalytic activity and outstanding long‐term durability, which outperforms the commercial Pt/C||RuO2 electrocatalyst.

Heavy metal pollution, such as lead, can cause contamination of water resources and harm human life. Many techniques have been explored and utilized to overcome this problem, with adsorption technology being the most common strategies for water treatment. In this study, carbon nanofibers, polyacrylonitrile (PAN)/sago lignin (SL) carbon nanofibers (PAN/SL CNF) and PAN/SL activated carbon nanofibers (PAN/SL ACNF), with a diameter approximately 300 nm, were produced by electrospinning blends of polyacrylonitrile and sago lignin followed by thermal and acid treatments and used as adsorbents for the removal of Pb(II) ions from aqueous solutions. The incorporation of biodegradable and renewable SL in PAN/SL blends fibers produces the CNF with a smaller diameter than PAN only but preserves the structure of CNF. The adsorption of Pb(II) ions on PAN/SL ACNF was three times higher than that of PAN/SL CNF. The enhanced removal was due to the nitric acid treatment that resulted in the formation of surface oxygenated functional groups that promoted the Pb(II) ions adsorption. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. The adsorption data fitted the Langmuir isotherm and the pseudo-second-order kinetic models, indicating that the adsorption is a monolayer, and is governed by the availability of the adsorption sites. With the adsorption capacity of 588 mg/g, determined via the Langmuir isotherm model, the study demonstrated the potential of PAN/SL ACNFs as the adsorbent for the removal of Pb(II) ions from aqueous solution.

Graphitic carbon nitride (g-C3N4)-supported ferric oxide (Fe2O3) nanocomposite modified with carbon nanofibers (CNFs) has been synthesized for the first time for photocatalytic H2-generation and the degradation of aqueous organics. In its first dual role, Fe2O3 served as the photocatalyst and the chemical vapor deposition (CVD) catalyst to grow CNFs over the g-C3N4 substrate. Time of CVD was found to be critical for synthesizing Fe2O3-CNF/g-C3N4 with a good photocatalytic efficiency. The synthesized materials were characterized for various physicochemical and photocatalytic properties. The creation of a Z-scheme heterostructure between g-C3N4 and Fe2O3 resulted in the greater H2-generation rate (2095 µmol/g h) than that (1119 µmol/g h) over the substrate. The photocatalytic degradation data showed ~ 95 and 91% removal of methylene blue and 4-nitrophenol in 180 and 300 min, respectively at 22 °C using the Fe2O3-CNF/g-C3N4 dose of 0.5 mg/mL. The photocatalytic reactions followed the indirect Z-scheme charge transfer path, with the graphitic CNFs acting as the electron-transfer medium between Fe2O3 and g-C3N4. The simple fabrication route and high photocatalytic efficiency of the ternary CNF-bridged Fe2O3-g-C3N4 composite system indicate the utility of the material in integrated environmental and energy applications including microbial fuel cells and microelectrolysis cells.

Tissue engineering makes it possible to fabricate scaffolds that can help the function of defective tissues or even the most complex organs such as the heart. Carbon nanofibers (CNFs), because of their high mechanical strength and electrical properties, can improve the functional coupling of cardiomyocytes and their electrophysiological properties. In this study, electroactive CNF/gelatin (Gel) nanofibrous cardiac patches were prepared by an electrospinning method. Scanning electron microscope (SEM) evaluation of prepared scaffolds showed randomly oriented nanofibers. The electrical conductivity of the CNF/Gel scaffolds was assessed by a four-probe device and was in the semiconducting range (~ 10−5 S/m). The result of an MTT assay confirmed the excellent biocompatibility of electroactive CNF/Gel scaffolds. Also, CNF-containing scaffolds supported cardiomyocyte adhesion and increased expression of the cardiac genes including TrpT-2, Actn4, and Conx43 compared with the non-conductive counterpart. Our findings also confirmed the angiogenic potential of CNF/Gel scaffolds as compatible and electroactive platforms for cardiac tissue engineering.

The hurdle of fabricating asymmetric supercapacitor (ASC) devices using a faradic cathode and a double layer anode is challenging due to the required large amount of active mass of anodic material compared to that of the cathodic material during mass balancing due to the large difference in capacitance values of the two electrodes. Here, the problem is addressed by engineering a negative electrode that furnishes an ultrahigh capacitance. An in situ developed metal–organic framework (MOF)‐based thermal treatment is adopted to grow highly porous N‐doped carbon nanotubes (CNTs) containing submerged Co nanoparticles over nano‐fibrillated electrospun hollow carbon nanofibers (HCNFs). The optimized CNT@HCNF‐1.5 furnishes an ultrahigh capacitance approaching 712 F g–1 with excellent rate capability. The capacitance reported from this work is the highest for any carbonaceous material reported to date. The CNT@HCNF‐1.5 is further used to fabricate symmetric supercapacitors (SSCs), as well as ASC devices. Remarkably, both the SSC and ASC devices furnish incredible performances in all aspects of SCs, such as a high energy density, long cycle life, and high rate capability, displaying decent practical applicability. The energy density of the SSC device reaches as high as 20.13 W h kg–1, whereas that of ASC approaches 87.5 W h kg–1. An in situ developed metal–organic framework‐based thermal treatment technique is adopted to prepare porous N‐doped carbon nanotubes containing firmly submerged Co‐nanoparticles over nano‐fibrillated electrospun hollow carbon nanofibers. When the optimized CNT@HCNF‐1.5 is applied as a negative electrode, the problem related to mass balancing during fabrication of asymmetric supercapacitor can be addressed satisfactorily that will open new possibilities for the future works.

Nonenzymatic biosensors do not require enzyme immobilization nor face degradation problem. Hence, nonenzymatic biosensors have recently attracted growing attention due to the stability and reproducibility. Here, a comparative study was conducted to quantitatively evaluate the glucose sensing of pure/oxidized Ni, Co, and their bimetal nanostructures grown on electrospun carbon nanofibers (ECNFs) to provide a low-cost free-standing electrode. The prepared nanostructures exhibited sensitivity (from 66.28 to 610.6 μA mM−1 cm−2), linear range of 2–10 mM, limit of detection in the range of 1 mM, and the response time (< 5 s), besides outstanding selectivity and applicability for glucose detection in the human serum. Moreover, the oxidizable interfering species, such as ascorbic acid (AA), uric acid (UA), and dopamine (DA), did not cause interference. Co–C and Ni-C phase diagrams, solid-state diffusion phenomena, and rearrangement of dissolved C atoms after migration from metal particles were discussed. This study undoubtedly provides new prospects on the nonenzymatic biosensing performance of mono-metal, bimetal, and oxide compounds of Ni and Co elements, which could be quite helpful for the fabrication of biomolecules detecting devices.

In this present study, we explored the catalytic behaviors of the in situ generated metal nanoparticles, i.e., Pt/Ni, embedded in laser-induced carbon nanofibers (LCNFs) and their potential for H 2 O 2 detection under physiological conditions. Furthermore, we demonstrate current limitations of laser-generated nanocatalyst embedded within LCNFs as electrochemical detectors and possible strategies to overcome the issues. Cyclic voltammetry revealed the distinctive electrocatalytic behaviors of carbon nanofibers embedding Pt and Ni in various ratios. With chronoamperometry at  +0.5 V, it was found that modulation of Pt and Ni content affected only current related to H 2 O 2 but not other interfering electroactive substances, i.e., ascorbic acid (AA), uric acid (UA), dopamine (DA), and glucose. This implies that the interferences react to the carbon nanofibers regardless of the presence of metal nanocatalysts. Carbon nanofibers loaded only with Pt and without Ni performed best in H 2 O 2 detection in phosphate-buffered solution with a limit of detection (LOD) of 1.4 µM, a limit of quantification (LOQ) of 5.7 µM, a linear range from 5 to 500 µM, and a sensitivity of 15 µA mM −1  cm −2 . By increasing Pt loading, the interfering signals from UA and DA could be minimized. Furthermore, we found that modification of electrodes with nylon improves the recovery of H 2 O 2 spiked in diluted and undiluted human serum. The study is paving the way for the efficient utilization of laser-generated nanocatalyst-embedding carbon nanomaterials for non-enzymatic sensors, which ultimately will lead to inexpensive point-of-need devices with favorable analytical performance. Graphical abstract

There is an urgent need to explore alternatives to replace traditional carbonaceous materials because of dwindling oil reserves and increasing atomospheric carbon dioxide. In the present study, the cellulose derived carbon nanofibers (CCNF) were prepared and used to hybridize with bismuth oxybromide to prepare novel photocatalyst composites (CCNF/BiOBr). The structural properties of the prepared composites were then characterized. Afterwards, the photocatalytic performance of the CCNF/BiOBr composites was investigated through degrading rhodamine B (RhB) under continuous visible light irradiation. The results indicated that the pyrolysis process could convert the cellulose to carbon nanofiber with high graphitization degree. The photocatalytic performance of the CCNF/BiOBr composite was better than that of the pure BiOBr, which was ascribed to the introduction of the CCNF into the composite system. The present work provides a promising way to design new photocatalyst composites with desirable carbon alternatives from biomass materials for effective treatment of organic contaminants in water media. Graphical Abstract