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The electrical conductivity of carbon fibers can be used to enable the design of intrinsically smart carbon fiber reinforced plastics (CFRPs). Resistance and impedance measurements of the structural material itself can then be used to measure physical stimuli such as strain or damage without requiring a dedicated sensor to be installed. Measuring the resistance with high precision requires good electrical contact between the measurement equipment and the conductive carbon fibers. In the literature, many different combinations of surface contacting material and surface preparation procedures are used, but only seldomly compared to one another. This article aims to compare frequently used electrical contact methods by analyzing their contact resistance to a pultruded CFRP rod. Furthermore, this study explores the change of contact resistance with increasing mechanical strain. The results show that contact resistance is highly dependent on both the material used for contacting the fibers as well as the surface preparation technique. From the combinations analyzed in this article, the electrodeposition in combination with a surface treatment using concentrated sulphuric acid shows the most promising results. Full article

DNA-wrapped single-walled carbon nanotubes (DNA-SWCNTs) in stable dispersion are expected to be used as biosensors in the future, because they have the property of absorption of light in the near infrared (NIR) region, which is safe for the human body. However, this practical application requires the understanding of the DNA-SWCNTs’ detailed response characteristics. The purpose of this study is to predict, in detail, the response characteristics of the absorption spectra that result when the antioxidant catechin is added to oxidized DNA-SWCNTs, from a small amount of experimental data. Therefore, in the present study, we predicted the characteristics of the absorption spectra of DNA-SWCNTs using the Bayesian regularization backpropagation neural network (BRBPNN) model. The BRBPNN model was trained with the catechin concentration and initial absorption peaks as inputs and the absorption spectra after catechin addition as outputs. The accuracy of the predicted absorption peaks and wavelengths after the addition of catechin, as predicted by the BRBPNN model, was within 1% of the error of the experimental data. By inputting the catechin concentrations under hundreds of conditions into this BRBPNN model, we were able to obtain detailed prediction curves for the absorption peaks. This method has the potential to help to reduce the experimental costs and improve the efficiency of investigating the properties of high-cost materials such as SWCNTs. Full article

Carbon nanotubes (CNTs) offer unique properties that have the potential to address multiple issues in industry and material sciences. Although many synthesis methods have been developed, it remains difficult to control CNT characteristics. Here, with the goal of achieving such control, we report a bottom-up process for CNT synthesis in which monolayers of premade aluminum oxide (Al₂O₃) and iron oxide (Fe₃O₄) nanoparticles were anchored on a flat silicon oxide (SiO₂) substrate. The nanoparticle dispersion and monolayer assembly of the oleic-acid-stabilized Al₂O₃ nanoparticles were achieved using 11-phosphonoundecanoic acid as a bifunctional linker, with the phosphonate group binding to the SiO₂ substrate and the terminal carboxylate group binding to the nanoparticles. Subsequently, an Fe₃O₄ monolayer was formed over the Al₂O₃ layer using the same approach. The assembled Al₂O₃ and Fe₃O₄ nanoparticle monolayers acted as a catalyst support and catalyst, respectively, for the growth of vertically aligned CNTs. The CNTs were successfully synthesized using a conventional atmospheric pressure-chemical vapor deposition method with acetylene as the carbon precursor. Thus, these nanoparticle films provide a facile and inexpensive approach for producing homogenous CNTs. Full article

Carbon nanotube (CNT)/copper composites offer promise as lightweight temperature-stable electrical conductors for future electrical and electronic devices substituting copper. However, clarifying how constituent nanotube structures influence CNT/Cu electrical performances has remained a major research challenge. Here, we investigate the correlation between the CNT/Cu electrical performances and nanotube structure by preparing and characterizing composites containing nanotubes of different structural attributes. We prepared three types of composites—single-wall (SW)-CNT/Cu wires, SW-CNT/Cu pillars, and multi-wall (MW)-CNT/Cu wires. The composites were fabricated from the corresponding CNT templates by two-step Cu electrodeposition, which retains template nanotube attributes through the fabrication process. The nanotube characteristics (diameter, G/D, alignment, etc.) in each template as well as the internal structure and electrical performances of the corresponding composites were characterized. SW-CNT/Cu wires and pillars outperformed MW-CNT/Cu wires, showing ≈ 3× higher room-temperature four-probe conductivities (as high as 30–40% Cu-conductivity). SW-CNT/Cu also showed up to 4× lower temperature coefficients of resistances i.e., more temperature-stable conductivities than MW-CNT/Cu. Our results suggest that few-walled small-diameter nanotubes can contribute to superior temperature-stable CNT/Cu conductivities. Better CNT crystallinity (high G/D), fewer nanotube ends/junctions, and nanotube alignment may be additionally beneficial. We believe that these results contribute to strategies for improving CNT/Cu performances to enable the real-world application of these materials as Cu substitutes. Full article

Hydrochars from hydrothermal carbonization of different biowaste materials (dried dandelion, sawdust, coconut shell powder) formed in the presence of aqueous salt solutions were compared to those obtained by the common method in pure water. Hydrochars with increased carbon contents, pore volume and surface areas were specifically obtained from coconut shell powder in the presence of zinc chloride. Compositional and structural changes within the hydrochar products caused by the process conditions and/or the additive were characterized by solid state ¹³C NMR spectroscopy, proving that cellulose and, in particular, lignin units in the biomass are more easily attacked in the presence of the salt. Under saline conditions, a distinct particle break-up led to the creation of mesoporosity, as observable from hysteresis loops in nitrogen adsorption isotherms, which were indicative of the presence of pores with diameters of about 3 to 10 nm. The obtained hydrochars were still rich in functional groups which, together with the mesoporosity, indicates the compounds have a high potential for pollutant removal. This was documented by adsorption capacities for the methylene blue and methyl orange dyes, which exceeded the values obtained for other hydrochar-based adsorbers. A subsequent physical activation of the mesoporous hydrochars in steam at different temperatures and times resulted in a further drastic increase in the surface areas, of up to about 750 m²/g; however, this increase is mainly due to micropore formation coupled with a loss of surface functionality. Consequently, the adsorption capacity for the quite large dyes does not provide any further benefit, but the uptake of smaller gas molecules is favored. Full article

Owing to the remarkable chemical and physical properties, graphene has been widely investigated by researchers over the last 15 years. This review summarizes major synthetic methods such as mechanical exfoliation, liquid phase exfoliation, unzipping of carbon nanotube, oxidation-reduction, arc discharge, chemical vapor deposition, and epitaxial growth of graphene in silicon carbide. Recent advances in the application of graphene in graphene-based lithium ion batteries, supercapacitors, electrochemical sensors, transparent electrodes and environmental based remedies are discussed. Full article

Graphene nanoscrolls (GNS) are 1D carbon-based nanoparticles. In this study, they were investigated as a heterogeneous nucleating agent in the poly(lactic acid) (PLA) matrix. The isothermal and non-isothermal melting behavior and crystallization kinetics of PLA-GNS nanocomposites were investigated using a differential scanning calorimeter (DSC). Low GNS content not only accelerated the crystallization rate, but also the degree of crystallinity of PLA. The Avrami model was used to fit raw experimental data, and to evaluate the crystallization kinetics for both isothermal and non-isothermal runs through the nucleation and growth rate. Additionally, the effect of the dimensionality and structure of the nanoparticle on the crystallization behavior and kinetics of PLA is discussed. GNS, having a similar fundamental unit as CNT and GNP, were observed to possess superior mechanical properties when analyzed by the nanoindentation technique. The scrolled architecture of GNS facilitated a better interface and increased energy absorption with PLA compared to CNTs and GNPs, resulting in superior mechanical properties. Full article

Effective fluoride removal from water is a persistent global concern both for drinking water and wastewater treatment. According to World Health Organization (WHO), standards for the maximum contaminant level in drinking water cannot be higher than 1.5 mg F⁻ L⁻¹ since affects the skeletal and nervous systems of humans. Various technologies have been developed to decrease fluoride concentration from waters, such as adsorption, coagulation, precipitation and membrane separation. Membrane technology has been found to be a very effective technology, significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is a costly process. This review aims to discuss the recent studies using modified membranes for fluoride removal. Emphasis is given on cellulose-, polymer- and graphene-based membranes and is further discussing the modification of membranes with several metals that have been developed in the last years. It was observed that the main focus of the total publications has been on the use of polymer-based membranes. Most of the membranes applied for defluoridation exhibit greater efficiency at pH values close to that of drinking water (i.e., 6–8), and maximum treatment capacity was obtained with the use of a cellulose modified membrane [email protected] with a permeate flux of 2000 L m⁻² h⁻¹, following the carbon-based amyloid fibril nano-ZrO₂ composites (CAF-Zr) 1750 L m⁻². A technical-economic comparison study of NF and RO is also referred, concluding that NF membrane is slightly less expensive. Full article

Nanoarchitectonics has been recently proposed as a post-nanotechnology concept. It is the methodology to produce functional materials from nanoscale units. Carbon-based materials are actively used in nanoarchitectonics approaches. This review explains several recent examples of energy and related applications of carbon materials from the viewpoint of the nanoarchitectonics concept. Explanations and discussions are described according to the classification of carbon sources for nanostructured materials: (i) carbon nanoarchitectonics from molecules and supramolecular assemblies; (ii) carbon nanoarchitectonics from fullerenes; (iii) carbon nanoarchitectonics from biomass; and (iv) carbon nanoarchitectonics with composites and hybrids. Functional carbon materials can be nanoarchitected through various processes, including well-skilled organic synthesis with designed molecular sources; self-assembly of fullerenes under various conditions; practical, low-cost synthesis from biomass; and hybrid/composite formation with various carbon sources. These examples strikingly demonstrate the enormous potential of nanoarchitectonics approaches to produce functional carbon materials from various components such as small molecules, fullerene, other nanocarbons, and naturally abundant biomasses. While this review article only shows limited application aspects in energy-related usages such as supercapacitors, applications for more advanced cells and batteries, environmental monitoring and remediation, bio-medical usages, and advanced devices are also expected. Full article

A series of PtRu/carbon black catalysts were prepared by means of deposition-precipitation and reduced by various reducing agents. NaBH₄, HCHO and NaH₂PO₂, respectively, were used as the reduction agents. Some of the samples were reduced by various amounts of NaH₂PO₂ to investigate the effects of P/Pt ratios on the characteristics and activity of the catalyst. These catalysts were characterized by X-ray diffraction and transmission electron microscopy. The components of these catalysts were detected by X-ray fluorescence, X-ray photoelectron microscopy, and extended X-ray absorption of fine structures (EXAFS). The methanol oxidation ability of the catalysts was tested by cyclic voltammetry measurement. The results show that NaH₂PO₂ could effectively reduce the particle size of PtRu metal. It can suppress the growth of metal particles. In addition, the P/Pt ratio is crucial. The catalyst reduced by NaH₂PO₂ with a P/Pt ratio of 1.2 had the highest activity among all catalysts. It had the higher Pt and Ru metal contents and smaller metal particle size than the other catalysts. Its activity was 253.12 A/g, which is higher that than the commercial catalyst (Johnson Matthey H10100, 251.32 A/g). Full article

Atmospheric pressure plasma jets (APPJ) are widely used in industry for surface cleaning and chemical modification. In the recent past, they have gained more scientific attention especially in the processing of carbon nanomaterials. In this work, a novel power generation technique was applied to realize the stable discharge in N₂ (10 vol.% H₂) forming gas in ambient conditions. This APPJ was used to reduce solution-processed graphene oxide (GO) thin films and the result was compared with an established and optimized reduction process in a low–pressure capacitively coupled (CCP) radiofrequency (RF) hydrogen (H₂) plasma. The reduced GO (rGO) films were investigated by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Effective deoxygenation of GO was observed after a quick 2 s treatment by AAPJ. Further deoxygenation at longer exposure times was found to proceed with the expense of GO–structure integrity. By adding acetylene gas into the same APPJ, carbon nanomaterials on various substrates were synthesized. The carbon materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analyses. Fullerene-like particles and graphitic carbon with short carbon nanotubes were detected on Si and Ag surfaces, respectively. We demonstrate that the APPJ tool has obvious potential for the versatile processing of carbon nanomaterials. Full article

Multiwalled carbon nanotubes (MWCNTs) are a one-dimensional nanomaterial with several desirable material properties, including high mechanical tensile modulus and strength, high electrical conductivity, and good thermal conductivity. A wide variety of techniques have been optimized to synthesize MWCNTs and to fabricate thin films of MWCNTs. These synthesis and fabrication methods vary based on precursor materials, process parameters, and physical and chemical principals, and have a strong influence on the properties of the nanotubes and films. Thus, the fabrication methods determine the performance of devices that can exploit the advantageous material properties of MWCNTs. Techniques for the fabrication of carbon nanotubes and carbon nanotube thin films are reviewed, followed by a discussion of the use of MWCNTs as an electrode material for electrochemical double-layer supercapacitors (EDLCs). EDLCs feature high power density, excellent reversibility and lifetime, and improved energy density over electrolytic capacitors. Beyond surveying fabrication techniques previously explored for MWCNT electrodes, an alternative approach based on inkjet printing capable of depositing a small amount of active material is discussed. Such an approach allows for a high degree of control over electrode properties and can potentially reduce cost and active material waste, which are essential components to the gradual conversion to green energy. Full article

Sodium polyacrylate is the superabsorbent waterlock polymer used in disposable diapers, which are the third largest single consumer item in landfills. As diapers are difficult to recycle, their use produces an incredible amount of environmental waste. In the present article, we present a reliable and facile approach to transform sodium polyacrylate, the main constitute in the used diapers, in a carbon-based magnetic sorbent material, capable for use in environmental applications. A nanoporous carbon magnetic hybrid material was prepared by reacting NaPA with iron acetate species under chemical activation conditions. Analysis of the characterization results revealed, the creation of a nanoporous structure, with high specific surface area value (S_gBET = 611 m²/g), along with the formation of nanosized zero valent iron nanoparticles and iron carbide (Fe₃C), inside the carbon pore system. ⁵⁷Fe Mössbauer spectroscopy verified also the existence of these two main iron-bearing phases, as well as additional minor magnetic phases, such as Fe₃O₄ and γ-Fe₂O₃. Vibrating sample magnetometry (VSM) measurements of the obtained hybrid confirmed its ferromagnetic/ferrimagnetic behavior. The hybrid material demonstrated a rapid sorption of Cr(VI) ions (adsorption capacity: 90 mg/g, 24 h, pH = 3). The results showed highly pH-dependent sorption efficiency of the hybrids, whereas a pseudo-second-order kinetic model described their kinetics. Full article

While first-row transition metal cations, notably Fe(+), catalyze the gas-phase conversion of acetylene to benzene, a distinct path is chosen in systems with Os, Ir, and Rh cations. Rather than losing the metal cation M(+) from the benzene–M(+) complex, as is observed for the Fe(+) system, the heavy metal ions activate CH bonds. The landmark system C₄H₄-Os(+) reacts with acetylene to produce C₆H₄-Os(+) and dihydrogen. Following our work on isomers of the form C_2nH_2n-Fe(+), we show by DFT modeling that the CH bonds of the metalla-7-cycle structure, C₆H₆-Os(+), are activated and define the gas-phase reaction path by which H₂ is produced. The landmark structures on the network of reaction paths can be used as a basis for the discussion of reactions in which a single Os atom on an inert surface can assist reactions of hydrocarbons. Full article

In this paper, carbon thin films were grown using the plasma-enhanced atomic layer deposition (PE-ALD). Methane (CH₄) was used as the carbon precursor to grow the carbon thin film. The grown film was analyzed by the high-resolution transmission electron micrograph (TEM), X-ray photoelectron spectroscopy (XPS) analysis, and Raman spectrum analysis. The analyses show that the PE-ALD-grown carbon film has an amorphous structure. It was found that the existence of defective sites (nanoscale holes or cracks) on the substrate of copper foil could facilitate the formation of nanolayered carbon films. The mechanism for the formation of nanolayered carbon film in the nanoscale holes was discussed. This finding could be used for the controlled growth of nanolayered carbon films or other two-dimensional nanomaterials while combining with modern nanopatterning techniques. Full article

With the aim of determining the best input geometry for DFT calculations of [60]PCBM, the geometry of 24 chemically possible [60]PCBM conformers were optimised and their electronic energies and average bond strains were determined. A DFT analysis of the relevant dihedral angles provided insights into the dynamical behaviour of the ester group through sterically restricted bond rotations. In addition, the ¹³C NMR spectra of the six better performing conformers were simulated and compared with an experiment. There is a close correlation between average bond strain, total electronic energy and mean absolute error of the simulated ¹³C NMR spectra of the ester carbons. The best overall candidate conformer for the input geometry had the C61-C4, C4-C3 and C3-C2 single bonds of the alkyl chain in syn, anti and anti arrangements, respectively, and had the C2-C1 and C1-O single bonds of the ester in syn and anti arrangements, respectively. This contrasts strikingly with most representations of PCBM in the literature, which depict all relevant bonds in anti arrangements. Full article

Stepping into the 21st century, “graphene fever” swept the world due to the discovery of graphene, made of single-layer carbon atoms with a hexagonal lattice. This wonder material displays impressive material properties, such as its electrical conductivity, thermal conductivity, and mechanical strength, and it also possesses unique optical and magnetic properties. Many researchers see graphene as a game changer for boosting the performance of various applications. Emerging consumer electronics and electric vehicle technologies require advanced battery systems to enhance their portability and driving range, respectively. Therefore, graphene seems to be a great candidate material for application in high-energy-density/high-power-density batteries. The “graphene battery”, combining two Nobel Prize-winning concepts, is also frequently mentioned in the news and articles all over the world. This review paper introduces how graphene can be adopted in Li-ion/Li metal battery components, the designs of graphene-enhanced battery materials, and the role of graphene in different battery applications. Full article

This work characterises thermal properties of a typical epoxy-based carbon-fibre-reinforced polymer used in aircraft construction, but with an out-of-plane fibre orientation, and assesses its potential as a structural ablative material. Samples of the commercially available Hexply^® 8552/IM7 are prepared with out-of-plane angles up to 90°, with a focus on 0° to 15°, enhancing thermal conductivity through the thickness of the panel. Ablation processes are simulated by a hot-air blower at 580 °C, and examined in detail by ultrasonic testing and microfocused computed X-ray tomography afterwards. Matrix degradation is characterised by infrared spectroscopy and mass loss. To assess structural properties, tensile, compression, and bending tests are performed. The results show a loss in mechanical performance with an increasing fibre angle, which may be negligible for angles lower than ~5° in the initial state. Composite material with an out-of-plane fibre orientation is deeply penetrated concerning matrix degradation by thermal loading, but it is held together by the fibres fixed in the intact matrix underneath. This type of material shows a high potential for structural components in single-use, high-temperature, ablative applications with a focus on saving weight. Full article

In late 2013, an open call for charcoal and biochar samples was distributed in an effort to compare a wide range of char samples by Raman spectroscopy. The samples contributed to this survey included: laboratory produced biochars, recent biochars produced in field conditions, and ancient char samples previously analysed by carbon dating. By using selected Raman measurements, the char samples could be ranked in terms of the degree of thermochemical alteration or extent of carbon nanostructural development. The Raman results for recently produced biomass chars were generally consistent with the conversion of amorphous carbon formed at lower temperatures into condensed, polyaromatic, and graphene-like carbon formed at higher temperatures. A number of parameters calculated from the Raman spectra could be used to estimate the effective heat treatment temperatures in the recently produced biochars. Other samples such as anthracite coal, tire pyrolysis carbon, and ancient chars departed from the trends observed in the recently produced biomass chars using this approach. In total, 45 samples were analysed by Raman spectroscopy for this survey. Ancient and buried char samples displayed higher intensities for features in the Raman spectra associated with amorphous carbon. Full article