Showing papers on "Carbon nanotube published in 2015"
TL;DR: Recently, carbonaceous nanofillers such as graphene and carbon nanotubes (CNTs) play a promising role due to their better structural, functional properties and broad range of applications in every field as mentioned in this paper.
1,097 citations
TL;DR: This work produces the most active HER catalyst based on iron pyrite, suggesting a scalable, low cost, and highly efficient catalyst for hydrogen generation.
Abstract: Hydrogen evolution reaction (HER) from water through electrocatalysis using cost-effective materials to replace precious Pt catalysts holds great promise for clean energy technologies. In this work we developed a highly active and stable catalyst containing Co doped earth abundant iron pyrite FeS2 nanosheets hybridized with carbon nanotubes (Fe1–xCoxS2/CNT hybrid catalysts) for HER in acidic solutions. The pyrite phase of Fe1–xCoxS2/CNT was characterized by powder X-ray diffraction and absorption spectroscopy. Electrochemical measurements showed a low overpotential of ∼0.12 V at 20 mA/cm2, small Tafel slope of ∼46 mV/decade, and long-term durability over 40 h of HER operation using bulk quantities of Fe0.9Co0.1S2/CNT hybrid catalysts at high loadings (∼7 mg/cm2). Density functional theory calculation revealed that the origin of high catalytic activity stemmed from a large reduction of the kinetic energy barrier of H atom adsorption on FeS2 surface upon Co doping in the iron pyrite structure. It is also fo...
752 citations
TL;DR: Freestanding, flexible paper is produced that exhibits high capacity and excellent stability when used as the electrode for Li-ion batteries and capacitors.
Abstract: 2D Nb2CTx MXene flakes are produced using an amine-assisted delamination process. Upon mixing with carbon nanotubes and filtration, freestanding, flexible paper is produced. The latter exhibits high capacity and excellent stability when used as the electrode for Li-ion batteries and capacitors.
688 citations
TL;DR: In this paper, the authors focus on the recent development in mechanical and tribological behavior of self-lubricating metallic nanocomposites reinforced by carbonous nanomaterials such as CNT and graphene.
Abstract: Rapid innovation in nanotechnology in recent years enabled development of advanced metal matrix nanocomposites for structural engineering and functional devices. Carbonous materials, such as graphite, carbon nanotubes (CNT's), and graphene possess unique electrical, mechanical, and thermal properties. Owe to their lubricious nature, these carbonous materials have attracted researchers to synthesize lightweight self-lubricating metal matrix nanocomposites with superior mechanical and tribological properties for several applications in automotive and aerospace industries. This review focuses on the recent development in mechanical and tribological behavior of self-lubricating metallic nanocomposites reinforced by carbonous nanomaterials such as CNT and graphene. The review includes development of self-lubricating nanocomposites, related issues in their processing, their characterization, and investigation of their tribological behavior. The results reveal that adding CNT and graphene to metals decreases both coefficient of friction and wear rate as well as increases the tensile strength. The mechanisms involved for the improved mechanical and tribological behavior is discussed.
673 citations
TL;DR: In this article, a variety of dimensional-structured nanocarbons were applied for the first time as metal-free catalysts to activate persulfate (PS) for catalytic oxidation of phenolics and dyes as well as their degradation intermediates.
Abstract: A variety of dimensional-structured nanocarbons were applied for the first time as metal-free catalysts to activate persulfate (PS) for catalytic oxidation of phenolics and dyes as well as their degradation intermediates. Single-walled carbon nanotubes (SWCNTs), reduced graphene oxide (rGO), and mesoporous carbon (CMK-8) demonstrated superior catalytic activities for heterogeneous PS activation, whereas fullerene (C60), nanodiamonds, and graphitic carbon nitride (g-C3N4) presented low efficiencies. Moreover, the carbocatalysts presented even better catalytic performances than activated carbon and metal oxides, such as Fe3O4, CuO, Co3O4, and MnO2. The activity of prepared rGO-900 was further competing to the most efficient electron donor of zerovalent iron (ZVI). Both characterization and oxidation results suggested that the catalytic performances of the nanocarbons are determined by the intrinsic atom arrangements of carbon hybridization, pore structure, defective sites, and functional groups (especially ...
597 citations
TL;DR: 3D hollow hybrid composites with ultrafine cobalt sulfide nanoparticles uniformly embedded within the well-graphitized porous carbon polyhedra/carbon nanotubes framework are rationally fabricated using a green and one-step method involving the simultaneous pyrolysis and sulfidation of ZIF-67.
Abstract: 3D hollow hybrid composites with ultrafine cobalt sulfide nanoparticles uniformly embedded within the well-graphitized porous carbon polyhedra/carbon nanotubes framework are rationally fabricated using a green and one-step method involving the simultaneous pyrolysis and sulfidation of ZIF-67. Because of the synergistic coupling effects favored by the unique nanohybridization, these composites exhibit high specific capacity, excellent cycle stability, and superior rate capability when evaluated as electrodes in lithium-ion batteries.
590 citations
TL;DR: The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.
Abstract: Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.
541 citations
TL;DR: A review of carbon nanotube reinforced composite (CNTRC) materials can be found in this article, where the concept of functionally graded (FG) pattern of reinforcement has been applied for functionally graded carbon nanite reinforced composite materials.
541 citations
TL;DR: It is shown that the surface-area-normalized activity for CO2 reduction is linearly correlated with GB surface density on Au/CNT, demonstrating that GB engineering is a powerful approach to improving the catalytic activity of metal NPs.
Abstract: Uncovering new structure–activity relationships for metal nanoparticle (NP) electrocatalysts is crucial for advancing many energy conversion technologies. Grain boundaries (GBs) could be used to stabilize unique active surfaces, but a quantitative correlation between GBs and catalytic activity has not been established. Here we use vapor deposition to prepare Au NPs on carbon nanotubes (Au/CNT). As deposited, the Au NPs have a relatively high density of GBs that are readily imaged by transmission electron microscopy (TEM); thermal annealing lowers the density in a controlled manner. We show that the surface-area-normalized activity for CO2 reduction is linearly correlated with GB surface density on Au/CNT, demonstrating that GB engineering is a powerful approach to improving the catalytic activity of metal NPs.
536 citations
TL;DR: A critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discusses the perspectives and challenges in this rapidly developing field of practical significance.
Abstract: Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.
535 citations
TL;DR: A review of the state of the art of gas sensors based on graphene and metal oxide hybrid nanostructures for detection of various common toxic gases is presented in this paper, where the authors have explored the hybrid architectures formed by blending of nanoparticles of metal-oxides with graphene or its derivatives.
Abstract: Sensing of gas molecules is critical to environmental monitoring, control of chemical processes, agricultural, and medical applications In particular, the detection of industrial toxic gases such as CO, NO x , and NH 3 is very important for many industries Metal oxides have been widely studied for the sensitivity of their properties to gases even though they do have some limitations Recently, graphene has been considered as a promising material for gas sensing since its electronic properties are strongly affected by the adsorption of foreign molecules Intrinsic graphene has high sensitivity at low gas concentrations; but the sensor selectivity is poor which limits its use in many practical applications Hence, hybrid architectures formed by blending of nanoparticles of metal–oxides with graphene or its derivatives have been explored by several researchers which showed improved gas sensing ability, especially the sensitivity and selectivity at room temperature Here we review the state of the art of gas sensors based on graphene and metal oxide hybrid nanostructures for detection of various common toxic gases
TL;DR: It is reported that carbon nanotubes, doped with nitrogen to form resident electron-rich defects, can act as highly efficient and, more importantly, stable catalysts for the conversion of CO2 to CO.
Abstract: The challenge in the electrosynthesis of fuels from CO2 is to achieve durable and active performance with cost-effective catalysts. Here, we report that carbon nanotubes (CNTs), doped with nitrogen to form resident electron-rich defects, can act as highly efficient and, more importantly, stable catalysts for the conversion of CO2 to CO. The unprecedented overpotential (-0.18 V) and selectivity (80%) observed on nitrogen-doped CNTs (NCNTs) are attributed to their unique features to facilitate the reaction, including (i) high electrical conductivity, (ii) preferable catalytic sites (pyridinic N defects), and (iii) low free energy for CO2 activation and high barrier for hydrogen evolution. Indeed, DFT calculations show a low free energy barrier for the potential-limiting step to form key intermediate COOH as well as strong binding energy of adsorbed COOH and weak binding energy for the adsorbed CO. The highest selective site toward CO production is pyridinic N, and the NCNT-based electrodes exhibit no degradation over 10 h of continuous operation, suggesting the structural stability of the electrode.
TL;DR: It is shown that, upon mild surface oxidation, hydrothermal annealing and electrochemical activation, multiwall carbon nanotubes (MWCNTs) themselves are effective water oxidation catalysts, which can initiate the oxygen evolution reaction (OER) at overpotentials of 0.3 V in alkaline media.
Abstract: Large-scale storage of renewable energy in the form of hydrogen (H2) fuel via electrolytic water splitting requires the development of water oxidation catalysts that are efficient and abundant. Carbon-based nanomaterials such as carbon nanotubes have attracted significant applications for use as substrates for anchoring metal-based nanoparticles. We show that, upon mild surface oxidation, hydrothermal annealing and electrochemical activation, multiwall carbon nanotubes (MWCNTs) themselves are effective water oxidation catalysts, which can initiate the oxygen evolution reaction (OER) at overpotentials of 0.3 V in alkaline media. Oxygen-containing functional groups such as ketonic C═O generated on the outer wall of MWCNTs are found to play crucial roles in catalyzing OER by altering the electronic structures of the adjacent carbon atoms and facilitates the adsorption of OER intermediates. The well-preserved microscopic structures and highly conductive inner walls of MWCNTs enable efficient transport of the electrons generated during OER.
TL;DR: A simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes is reported.
Abstract: In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g−1, areal capacitance: 1.11 F cm−2) which leads to an exceptionally high energy density of 39.28 Wh kg−1 and power density of 128.01 kW kg−1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.
TL;DR: A large-area and free-standing 2D supramolecular polymer single-layer sheet, comprising triphenylene-fused nickel bis(dithiolene) complexes has been readily prepared by using the Langmuir-Blodgett method, which exhibits excellent electrocatalytic activities for hydrogen generation from water and an overpotential superior to that of recently reported carbon nanotube supported molecular catalysts and heteroatom-doped graphene catalysts.
Abstract: The rational construction of covalent or noncovalent organic two-dimensional nanosheets is a fascinating target because of their promising applications in electronics, membrane technology, catalysis, sensing, and energy technologies. Herein, a large-area (square millimeters) and free-standing 2D supramolecular polymer (2DSP) single-layer sheet (0.7-0.9 nm in thickness), comprising triphenylene-fused nickel bis(dithiolene) complexes has been readily prepared by using the Langmuir-Blodgett method. Such 2DSPs exhibit excellent electrocatalytic activities for hydrogen generation from water with a Tafel slope of 80.5 mV decade(-1) and an overpotential of 333 mV at 10 mA cm(-2) , which are superior to that of recently reported carbon nanotube supported molecular catalysts and heteroatom-doped graphene catalysts. This work is promising for the development of novel free-standing organic 2D materials for energy technologies.
TL;DR: In this article, the authors summarize the latest progress in polyoxometalates (POMs) and carbon nanotubes (CNTs) nanocomposites with a focus on energy materials for water splitting and fuel cells, composite electrode materials for batteries and supercapacitors as well as composites for environmental pollutant sensing.
Abstract: Composites based on polyoxometalates (POMs) and nanostructured carbon such as carbon nanotubes (CNTs) or graphene have attracted widespread attention as they combine the unique chemical reactivity of POMs with the unparalleled electronic properties of nanocarbons. The exceptional properties of these composites have been employed in catalysis, energy conversion and storage, molecular sensors and electronics. Herein, we summarize the latest progress in POM/CNT and POM/graphene nanocomposites with a focus on energy materials for water splitting and fuel cells, composite electrode materials for batteries and supercapacitors as well as composites for environmental pollutant sensing. Current applications are critically assessed and promising future target systems are discussed.
TL;DR: A facile and scalable strategy to fabricate hierarchical porous MWCNTs/Co3O4 nanocomposites has been reported, with the help of a morphology-maintained annealing treatment of carbon nanotubes inserted metal organic frameworks (MOFs).
Abstract: Hybridizing nanostructured metal oxides with multiwalled carbon nanotubes (MWCNTs) is highly desirable for the improvement of electrochemical performance of lithium-ion batteries. Here, a facile and scalable strategy to fabricate hierarchical porous MWCNTs/Co3O4 nanocomposites has been reported, with the help of a morphology-maintained annealing treatment of carbon nanotubes inserted metal organic frameworks (MOFs). The designed MWCNTs/Co3O4 integrates the high theoretical capacity of Co3O4 and excellent conductivity as well as strong mechanical/chemical stability of MWCNTs. When tested as anode materials for lithium-ion batteries, the nanocomposite displays a high reversible capacity of 813 mAh g–1 at a current density of 100 mA g–1 after 100 charge–discharge cycles. Even at 1000 mA g–1, a stable capacity as high as 514 mAh g–1 could be maintained. The improved reversible capacity, excellent cycling stability, and good rate capability of MWCNTs/Co3O4 can be attributed to the hierarchical porous structure...
TL;DR: In this paper, a carbon shell-protection solution was proposed and a ferroferric oxide-carbon (Fe3O4-C) binder-free nanorod array anode exhibiting much improved cyclic stability (from only hundreds of times to >5000 times), excellent rate performance, and a high capacity of ≈7776.36 C cm−3 (≈0.4278 C cm −2; 247.5 mAh g−1, 71.4% of the theoretical value) in alkaline electrolyte.
Abstract: Iron oxides are promising to be utilized in rechargeable alkaline battery with high capacity upon complete redox reaction (Fe3+ Fe0). However, their practical application has been hampered by the poor structural stability during cycling, presenting a challenge that is particularly huge when binder-free electrode is employed. This paper proposes a “carbon shell-protection” solution and reports on a ferroferric oxide–carbon (Fe3O4–C) binder-free nanorod array anode exhibiting much improved cyclic stability (from only hundreds of times to >5000 times), excellent rate performance, and a high capacity of ≈7776.36 C cm−3 (≈0.4278 C cm−2; 247.5 mAh g−1, 71.4% of the theoretical value) in alkaline electrolyte. Furthermore, by pairing with a capacitive carbon nanotubes (CNTs) film cathode, a unique flexible solid-state rechargeable alkaline battery-supercapacitor hybrid device (≈360 μm thickness) is assembled. It delivers high energy and power densities (1.56 mWh cm−3; 0.48 W cm−3/≈4.8 s charging), surpassing many recently reported flexible supercapacitors. The highest energy density value even approaches that of Li thin-film batteries and is about several times that of the commercial 5.5 V/100 mF supercapacitor. In particular, the hybrid device still maintains good electrochemical attributes in cases of substantially bending, high mechanical pressure, and elevated temperature (up to 80 °C), demonstrating high environmental suitability.
TL;DR: In this article, an asymmetric supercapacitors are fabricated using coaxial CNT/Ni(OH) 2 composites as positive electrode and reduced graphene oxide (rGO) as negative electrode.
TL;DR: Both G-CNTm and GNm possessed excellent antifouling performance for SA and HA but inferior for BSA because of the strong interaction between protein and graphene sheets.
Abstract: A sort of novel high-flux nanofiltration membrane was fabricated by synergistic assembling of graphene and multiwalled carbon nanotubes (MWNTs), in which graphene played the role of molecular sieving and MWNTs expanded the interlayer space between neighbored graphene sheets. The MWNT-intercalated graphene nanofiltration membrane (G-CNTm) showed a water flux up to 11.3 L m(-2) h(-1) bar(-1), more than 2 times that of the neat graphene nanofiltration membrane (GNm), while keeping high dye rejection (>99% for Direct Yellow and >96% Methyl Orange). The G-CNTm also showed good rejection ratio for salt ions (i.e., 83.5% for Na2SO4, 51.4% for NaCl). We also explored the antifouling performance of G-CNTm and GNm with bovine serum albumin (BSA), sodium alginate (SA) and humic acid (HA). Both G-CNTm and GNm possessed excellent antifouling performance for SA and HA but inferior for BSA because of the strong interaction between protein and graphene sheets.
TL;DR: This review considers recent developments in the use of carbon nanoparticles and nanostructures as sensors and considers how they can be used to detect a diverse range of analytes.
Abstract: Carbon nanomaterials are among the most broadly discussed, researched and applied of synthetic nanomaterials. The structural diversity of these materials provides an array of unique electronic, magnetic and optical properties, which when combined with their robust chemistry and ease of manipulation, makes them attractive candidates for sensor applications. Furthermore, the biocompatibility exhibited by many carbon nanomaterials has seen them used as in vivo biosensors. Carbon nanotubes, graphene and carbon dots have come under intense scrutiny, as either discrete molecular-like sensors, or as components which can be integrated into devices. In this review we consider recent developments in the use of carbon nanoparticles and nanostructures as sensors and consider how they can be used to detect a diverse range of analytes.
TL;DR: This review compares different carbon nanomaterial strategies for creating electrochemical sensors for biomolecules and addresses enzyme-based electrodes that are used to detect non-electroactive species such as glucose, alcohols, and proteins.
TL;DR: Nitrogen-doped carbon nanotubes have been considered as a promising electrocatalyst for carbon-dioxide-reduction reactions, but two fundamental chemistry questions remain obscure: what are the active centers with respect to various defect species and what is the role of defect density on the selectivity of NCNTs?
Abstract: Nitrogen-doped carbon nanotubes (NCNTs) have been considered as a promising electrocatalyst for carbon-dioxide-reduction reactions, but two fundamental chemistry questions remain obscure: 1) What are the active centers with respect to various defect species and 2) what is the role of defect density on the selectivity of NCNTs? The aim of this work is to address these questions. The catalytic activity of NCNTs depends on the structural nature of nitrogen in CNTs and defect density. Comparing with pristine CNTs, the presence of graphitic and pyridinic nitrogen significantly decreases the overpotential (ca. −0.18 V) and increases the selectivity (ca. 80 %) towards the formation of CO. The experimental results are in congruent with DFT calculations, which show that pyridinic defects retain a lone pair of electrons that are capable of binding CO2. However, for graphitic-like nitrogen, electrons are located in the π* antibonding orbital, making them less accessible for CO2 binding.
TL;DR: In this article, an asymmetric supercapacitor with Ni-MOF/CNTs as the positive electrode and reduced graphene oxide/graphitic carbon nitride (rGO/g-C3N4) as the negative electrode was fabricated, and this device could be operated in a working voltage range of 0.6 V based on a complementary potential window in 6 M KOH aqueous electrolyte, delivering a high energy density of 36.6 W h kg−1 at a power density of 480 W kg− 1.
Abstract: Currently, metal–organic frameworks (MOFs) have been attracting great interest as a new kind of electrode material for energy storage devices, because their porous skeleton would benefit the access and transport of electrolytes, and the exposure of metal ions can offer more active sites to electrolytes. In this study, we have successfully fabricated nickel metal–organic framework/carbon nanotube (Ni-MOF/CNT) composites, which show excellent electrochemical performance due to the synergistic effects of the Ni-MOF specific structure and CNTs with high conductivity, achieving a high specific capacitance of 1765 F g−1 at a current density of 0.5 A g−1. To further explore the capacitive performance of the composite electrode, an asymmetric supercapacitor device using Ni-MOF/CNTs as the positive electrode and reduced graphene oxide/graphitic carbon nitride (rGO/g-C3N4) as the negative electrode was fabricated, and this device could be operated in a working voltage range of 0–1.6 V based on a complementary potential window in 6 M KOH aqueous electrolyte, delivering a high energy density of 36.6 W h kg−1 at a power density of 480 W kg−1. Moreover, this asymmetric supercapacitor revealed an excellent cycle life along with 95% specific capacitance retention after 5000 consecutive charge–discharge tests. These outstanding performances would make MOFs become one of the most promising candidates for the future high energy storage systems.
TL;DR: A new method for evaluating the elastic properties of the interfacial region is developed by examining the fracture behavior of carbon nanotube reinforced poly (methyl methacrylate) matrix composites under tension using molecular dynamics simulations.
Abstract: The remarkable mechanical properties of carbon nanotubes, such as high elastic modulus and tensile strength, make them the most ideal and promising reinforcements in substantially enhancing the mechanical properties of resulting polymer/carbon nanotube composites. It is acknowledged that the mechanical properties of the composites are significantly influenced by interfacial interactions between nanotubes and polymer matrices. The current challenge of the application of nanotubes in the composites is hence to determine the mechanical properties of the interfacial region, which is critical for improving and manufacturing the nanocomposites. In this work, a new method for evaluating the elastic properties of the interfacial region is developed by examining the fracture behavior of carbon nanotube reinforced poly (methyl methacrylate) (PMMA) matrix composites under tension using molecular dynamics simulations. The effects of the aspect ratio of carbon nanotube reinforcements on the elastic properties, i.e. Young's modulus and yield strength, of the interfacial region and the nanotube/polymer composites are investigated. The feasibility of a three-phase micromechanical model in predicting the elastic properties of the nanocomposites is also developed based on the understanding of the interfacial region.
TL;DR: The chemical protonation of graphitic carbon nitride (CN) solids with strong oxidizing acids, for example HNO3, is demonstrated as an efficient pathway for the sol processing of a stable CN colloidal suspension, which can be translated into thin films by dip/disperse-coating techniques.
Abstract: The chemical protonation of graphitic carbon nitride (CN) solids with strong oxidizing acids, for example HNO3, is demonstrated as an efficient pathway for the sol processing of a stable CN colloidal suspension, which can be translated into thin films by dip/disperse-coating techniques. The unique features of CN colloids, such as the polymeric matrix and the reversible hydrogen bonding, result in the thin-film electrodes derived from the sol solution exhibiting a high mechanical stability with improved conductivity for charge transport, and thus show a remarkably enhanced photo-electrochemical performance. The polymer system can in principle be broadly tuned by hybridization with desired functionalities, thus paving the way for the application of CN for specific tasks, as exemplified here by coupling with carbon nanotubes.
TL;DR: In this article, the authors used the Langmuir, Freundlich and Temkin isotherms to describe the behavior of equilibrium adsorption of the studied mercury ions.
Abstract: Nanocomposites of silica incorporated with carbon nanotubes (silica/CNT) and activated carbon (silica/AC) were synthesized and characterized by scanning electron microscopy (SEM), element mapping, energy dispersive X-ray spectroscopy (EDX), thermogravimetric analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR). Silica/CNT and silica/AC were investigated for efficient removal of mercury ions from aqueous solutions. The adsorbents have been analyzed on the basis of adsorption capacity, reusability, and their application in packed columns. The effects of experimental parameters, like pH, contact time and initial concentrations on the adsorption of mercury ions, were optimized. The kinetic data for the adsorption process obeyed a pseudo-second-order kinetic model with R2 of 0.999. Fitting the data to an intraparticle diffusion model indicated that surface adsorption and intraparticle diffusion were concurrently operating. In addition, this study used the Langmuir, Freundlich and Temkin isotherms to describe the behaviour of equilibrium adsorption. The equilibrium adsorption of the studied mercury ions is best fitted using the Freundlich isotherm, with silica/CNT of higher capacity than silica/AC. The silica/CNT showed better performance than silica/AC indicating silica/CNT has better efficiency.
TL;DR: In this article, a review summarizes the progresses in the sulfur-carbon composite cathodes for lithium-sulfur batteries in recent years, and introduces the roles and the effectiveness of various carbon structures on the electrochemical properties.
TL;DR: This fiber-based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density.
Abstract: One of challenges existing in fiber-based supercapacitors is how to achieve high energy density without compromising their rate stability. Owing to their unique physical, electronic, and electrochemical properties, two-dimensional (2D) nanomaterials, e.g., molybdenum disulfide (MoS2) and graphene, have attracted increasing research interest and been utilized as electrode materials in energy-related applications. Herein, by incorporating MoS2 and reduced graphene oxide (rGO) nanosheets into a well-aligned multi-walled carbon nanotube (MWCNT) sheet followed by twisting, MoS2-rGO/MWCNT and rGO/MWCNT fibers are fabricated, which can be used as the anode and cathode, respectively, for solid-state, flexible, asymmetric supercapacitors. This fiber-based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density.
TL;DR: A novel nitrogen-doped Fe/Fe3C@graphitic layer/carbon nanotube hybrid derived from MOFs has been first fabricated by a facile approach and exhibited outstanding bifunctional electrocatalytic activity for ORR and OER.