C, Volume 3, Issue 2 (June 2017) – 11 articles

In this paper, a graphene decorated SiC nanomaterial (graphene@SiC) fabricated via a facile adiabatic process was physicochemically characterised, then applied as a supercapacitor material and as an anode within a Li-ion battery (LIB). The reported graphene@SiC nanomaterial demonstrated excellent supercapacitative behaviour with a relatively high power density and specific capacitance of 4800 W·kg⁻¹ and 394 F·g⁻¹, respectively. In terms of its capabilities as an anode within an LIB, the layered-graphene overwhelms the Li-intercalation, which is reflected in the obtained specific capacity of 150 mAh·g⁻¹, with a columbic efficiency of ~99% (after 450 cycles) at a current of 100 mA·g⁻¹. Full article

A prototype design of a reactor for scalable functionalization of SWCNTs by the reaction of alkyl halides with Billups-Birch reduced SWCNTs is described. The Hauge apparatus is designed to allow for the safe handling of all the reagents and products under an inert atmosphere at controlled temperatures. The extent of reaction of Li/NH₃ solution with the SWCNTs is measured in-situ by solution conduction, while homogenous mixing is ensured by the use of a homogenizer, and thermocouple are placed at different heights within the reactor flask. Addition of an alkyl halide yield alkyl-functionalized SWCNTs, which may be isolated by solvent extraction leaving a solid sample that is readily purified by hydrocarbon extraction. As an example, reaction of SWCNT/Li/NH₃ with 1-iododecane yields dodecane-functionalized SWCNTs (C₁₂-SWCNTs), which have been characterized by TG/DTA, XPS, and Raman spectroscopy. Sample extraction during the reaction allows for probing of the rate of the reaction in order to determine the end point of the reaction, which for C₁₂-SWCNTs (at −78 °C) is 30 min. Full article

To ensure the availability of clean water for humans into the future, efficient and cost-effective water purification technology will be required. The rapidly decreasing quality of water and the growing global demand for this scarce resource has driven the pursuit of high-performance purification materials, particularly for application as point-of-use devices. This review will introduce the main types of natural and artificial contaminants that are present in water and the challenges associated with their effective removal. The efficiency and performance of recently developed materials for water purification, with a focus on activated carbon, carbon nanotubes and graphene will be discussed. The recent advances in water purification using these materials is reviewed and their applicability as point-of-use water purification systems discussed. Full article

The reaction of Group 6 metals with SWCNT has the potential to bridge the resistive SWCNT^…SWCNT junctions by the formation of “Cr(SWCNT)₂” complexes analogous to Cr(C₆H₆)₂. This study reports that the formation of such species is very sensitive to oxidation by a residual iron oxide catalyst used for the growth of the SWCNTs and adsorbed/bound oxygen functionality. The reaction of raw HiPco SWCNTs with M(CO)₆ and (C₇H₈)M(CO)₃ (M = Cr, W) or (C₆H₆)Cr(CO)₃ results in the formation of the Group 6 metal oxides. Annealing and acid treating the HiPco SWCNTs to reduce the catalyst content allows for the observation of zero valent metals by XPS, while the use of very high purity SWCNTs and graphene allows for the addition of primarily zero valent Group 6 metals, including the bis-hexahapto metal complex. Full article

The smallest fullerene C₂₀ with positive electron affinity is considered to be a new organic nano-electronic material. The binding structures and electronic states of lithium ions and atoms (Li⁺ and Li) trapped on the surface of C₂₀ have been investigated by means of density functional theory (DFT) calculation to elucidate the nature of their interaction. It was found that a Li⁺ can bind to only one site of C₂₀. This is, specifically, on top of the site where Li⁺ binds to the carbon atom of C₂₀. On the other hand, in the case of a Li atom, two structures were obtained besides the on-top structure. One was pentagonal structure which included a Li atom on a five-membered ring of C₂₀. The other was a triangular structure in which the Li atom bind to the the carbon–carbon bond of C₂₀. Finally, the nature of the interactions between Li ions or atoms and the C₂₀ cluster was discussed on the basis of theoretical results. Full article

Carbon nanotube (CNT) yarns are fiber-like materials that exhibit excellent mechanical, electrical and thermal properties. More importantly, they exhibit a piezoresistive response that can be tapped for sensing purposes. The objective of this study is to determine experimentally the piezoresistive response of CNT yarns that are embedded in a polymeric medium while subjected to either tension or compression, and compare it with that of the free or unconstrained CNT yarns. The rationale is the need to know the piezoresistive response of the CNT yarn while in a medium, which provides a lateral constraint to the CNT yarn, thus mimicking the response of integrated CNT yarn sensors. The experimental program includes the fabrication of samples and their electromechanical characterization. The CNT yarns are integrated in polymeric beams and subjected to four-point bending, allowing the determination of their response under tension and compression. The electromechanical data from a combined Inductance–Capacitance–Resistance (LCR) device and a mechanical testing system were used to determine the piezoresistive response of the CNT yarns. At a strain rate of 0.006 min⁻¹, the gauge factor obtained under tension for a maximum strain of 0.1% is ~29.3 which is higher than ~21.2 obtained under compression. The CNT yarn sensor exhibited strain rate dependence with a gauge factor of approximately 23.0 at 0.006 min⁻¹, in comparison to 19.0 and 1.3, which were obtained at 0.0005 min⁻¹ and 0.003 min⁻¹, respectively. There is a difference of up to two orders of magnitude in the sensitivity of the constrained CNT yarn under bending with respect to that of the free CNT yarn under uniaxial tension. However, the difference becomes smaller when the constrained CNT yarn was tested under uniaxial tension. This data and information will be used for future modeling efforts and to study the phenomena that occur when CNT yarns are integrated in polymeric and composite materials and structures. Full article

Our study is the first attempt to study the interaction between NaN3 and hydrated fullerenes C60 by means of a non-chemical reaction-based approach. The aim is to study deviations of signals obtained by ¹⁴N NMR spectroscopy to detect the binding interaction between sodium azide and hydrated fullerene. We considered ¹⁴N NMR spectroscopy as one of the most suitable methods for the characterization of azides to show resonance signals corresponding to the three non-equivalent nitrogen atoms. The results demonstrate that there are changes in the chemical shift positions and line-broadening, which are related to the different molar ratios of NaN₃:C60 in the samples. Full article

In this paper, wool carpet dye adsorption properties of nanoporous activated carbon materials (NCMs) prepared from bamboo agro-product is reported. Bamboo cane powder was chemically activated with phosphoric acid at different temperatures (400, 500, and 600 °C) at an impregnation ratio of 1:1. We found that the specific surface area and the total pore volume of NCM increases with temperature giving the highest surface area and pore volume ca. 2130 m²·g⁻¹ and 2.69 cc·g⁻¹ at 600 °C. Owing to superior surface textural properties, bamboo-derived NCM showed excellent adsorption capacity for wool carpet dyes Lanasyn orange (LO) and Lanasyn gray (LG). The adsorption phenomena could be described by Langmuir/Freundlich adsorption isotherm models. The maximum adsorption capacity was ca. 2.60 × 10³ and 3.04 × 10³ mg·g⁻¹ for LO and LG, respectively. The adsorption followed pseudo second order kinetics with the second order rate constant of 1.24 × 10⁻³ g·mg⁻¹·min⁻¹ (LO) and 7.69 × 10⁻⁴ g·mg⁻¹·min⁻¹ (LG), respectively. This study demonstrated that the high surface area NCMs prepared from agro-product can be used as efficient and cost-effective adsorbent materials for the removal of dyes from industrial effluent. Full article

Fossil fuels depletion and increasing environmental impacts arising from their use call for seeking growing supplies from renewable and nuclear primary energy sources. However, it is necessary to simultaneously attend to both the electrical power needs and the specificities of the transport and industrial sector requirements. A major question posed by the shift away from traditional fossil fuels towards renewable energy sources lies in matching the power demand with the daily and seasonal oscillation and the intermittency of these natural energy fluxes. Huge energy storage requirements become necessary or otherwise the decline of the power factor of both the renewable and conventional generation would mean loss of resources. On the other hand, liquid and gaseous fuels, for which there is vast storage and distribution capacity available, appear essential to supply the transport sector for a very long time ahead, besides their domestic and industrial roles. Within this context, the present assessment suggests that proven technologies and sound tested principles are available to develop an integrated energy system, relying on synthetic fuels. These would incorporate carbon capture and utilization in a closed carbon cycle, progressively relying mostly on solar and/or nuclear primary sources, providing both electric power and gaseous/liquid hydrocarbon fuels, having ample storage capacity, and able to timely satisfy all forms of energy demand. The principles and means are already available to develop a carbon-neutral synthetic fuel economy. Full article

Carbon nanostructures including carbon black, carbon nanotubes, graphite or graphene have attracted a tremendous interest as fillers for elastomeric compounds. The preparation methods of nanocomposites that have a strong impact on the state of filler dispersion and thus on the properties of the resulting composites, are briefly described. At a same filler loading, considerable improvement in stiffness is imparted to the host polymeric matrix by the carbon nanomaterials with regard to that provided by the conventional carbon black particles. It is mainly attributed to the high aspect ratio of the nanostructures rather than to strong polymer-filler interactions. The orienting capability of the anisotropic fillers under strain as well the formation of a filler network, have to be taken into account to explain the high level of reinforcements. A comparison of the efficiency of the different carbon nanostructures is carried out through their mechanical and electrical properties but no clear picture can be obtained since the composite properties are strongly affected by the state of filler dispersion. Full article