Carbonaceous Nanotubes Research Articles

A twisted carbonaceous nanotube as the air-electrode for flexible Zn-Air batteries.

Exploring electrocatalysts with high-efficiency oxygen reduction reaction (ORR) is significant for practical applications of fuel cells and metal-air batteries. In this work, a twisted core@shell material has been prepared with helical polypyrrole nanotubes (HPPys) as the core and coordination polymers (CPs) as the shell. After the pyrolysis process, a dense twisted carbon layer was formed by the reaction of CP and HPPy at its interface under Ar. The derived twisted carbonaceous nanotube exhibits good performance in both electrocatalytic ORR and OER. When used as the air-electrode in a flexible Zn-air battery, the battery shows good performance and stability.

Dry reforming of methane over sub-stoichiometric NiAl2O4-mediated Ni/Al2O3 catalysts

A series of Ni/Al2O3 catalysts were prepared from substoichiometric NiAl2O4 precursors (Ni/Al molar ratio between 0.5 and 0.05) were examined for the dry reforming of methane. The calcined spinel precursors and the corresponding reduced catalysts were characterised by N2 physisorption, X-ray fluorescence, X-ray diffraction, Raman spectroscopy, electronic microscopy coupled to elemental mapping, X-ray photoelectron spectroscopy and temperature-programmed techniques. Compared with the stoichiometric counterpart, nickel species present in Ni-deficient precursors were mostly in the form of a spinelic phase. After high-temperature reduction, narrow particle size distributions centred at 10 nm were obtained. The largest available nickel surface area (18 m2g−1) was exhibited by the catalyst derived from the precursor with a Ni/Al of 0.15. The NiAl2O4-mediated catalysts, especially those with Ni/Al molar ratio in the 0.15–0.25 range, exhibited a notable performance at 90,000 h−1 and 650 °C. The optimal catalyst (14%wt.%Ni), with 93%CH4 and 80%CO2 conversions, was also able to operate for 200 h despite the significant formation of carbonaceous nanotubes (around 1gCgCAT-1) and were examined.

The combined effect of carbon fiber and carbon nanotubes on the electrical and self-heating properties of cement composites

This work investigates the electrical and heating performance of conductive cement composites by using carbonaceous materials (carbon fibers (CF) and carbon nanotubes (CNT)) as conductive materials. Various volume fractions of carbonaceous materials were used to indicate the electrical heating performance of the cement composites. Experimental results showed that adding the carbonaceous materials in cement composites reduced the electrical resistance by more than 98% than that of the main cement paste. The percolation threshold of all carbonaceous cement composites was found to be between 0.1 and 0.75 vol%. By applying a potential voltage to the cement composites, different heating temperatures were investigated depending on the type of carbonaceous materials and their volume fractions. The conductive cement composites showed high heating performance exceeded 100°C within a record time when the input voltage is 60 V. At the end of the study, an analysis of electric power consumption was carried out to determine the feasibility of using carbonaceous materials as self-heating components in the suggested conductive cement composites.

Mechanistic Probing of Encapsulation and Confined Growth of Lithium Crystals in Carbonaceous Nanotubes (Adv. Mater. 51/2021)

Anode Materials In article number 2105228, Ming-Sheng Wang and co-workers reveal the encapsulation mechanism and confined growth kinetics of lithium crystals in carbonaceous nanotubes by in situ transmission electron microscopy. Unusual Li nanostructures such as 2D membranes and multi-crystal nanowires are discovered. Importantly, sufficient nitrogen/oxygen doping or pre-lithiation would be critical for the carbon hosts to reliably encapsulate Li metal in a battery anode.

Mechanistic Probing of Encapsulation and Confined Growth of Lithium Crystals in Carbonaceous Nanotubes.

Encapsulation of lithium in the confined spaces within individual nanocapsules is intriguing and highly desirable for developing high-performance Li metal anodes. This work aims for a mechanistic understanding of Li encapsulation and its confined growth kinetics inside 1D enclosed spaces. To achieve this, amorphous carbon nanotubes are employed as a model host using in situ transmission electron microscopy. The carbon shells have dual roles, providing geometric/mechanical constraints and electron/ion transport channels, which profoundly alter the Li growth patterns. Li growth/dissolution takes place via atom addition/removal at the free surfaces through Li+ diffusion along the shells in the electric field direction, resulting in the formation of unusual Li structures, such as poly-crystalline nanowires and free-standing 2D ultrathin (1-2nm) Li membranes. Such confined front-growth processes are dominated by Li {110} or {200} growing faces, distinct from the root growth of single-crystal Li dendrites outside the nanotubes. Controlled experiments show that high lithiophilicity/permeability, enabled by sufficient nitrogen/oxygen doping or pre-lithiation, is critical for the stable encapsulation of lithium inside carbonaceous nanocapsules. First-principles-based calculations reveal that N/O doping can reduce the diffusion barrier for Li+ penetration, and facilitate Li filling driven by energy minimization associated with the formation of low-energy Li/C interfaces.

Dual-Functional Template-Induced In Situ Polymerization Process Enables the Hierarchical Carbonaceous Nanotubes with Simultaneous Sn Cluster Incorporation and Nitrogen-Doping for Superior Potassium-Ion Storage.

Potassium ion-based energy storage devices have received extensive attention for grid-level applications due to their abundant natural resources and low cost. However, the large ionic radius of K+ leads to inferior capacities and cyclic stability, which hinders their practical application. Herein, hierarchical carbonaceous nanotubes with simultaneous ultrasmall Sn cluster incorporation and nitrogen doping (denoted as u-Sn@NCNTs) are fabricated using MnO2 nanowires as a dual-functional template (in situ polymerization and shape-directing agents) and subsequent carbonization treatment. The u-Sn@NCNTs exhibit a superior K+ storage capability with a high reversible capacity (220.1 mA h g-1 at 0.1 A g-1) and long cycling stability (149.9 mA h g-1 at 1 A g-1 after 4000 cycles). Besides, the u-Sn@NCNTs exhibit superior cycling stability up to 10000 cycles at 5 A g-1 for Na+ storage. The potassium storage mechanism and kinetics are investigated based on ex situ X-ray photoelectron spectroscopy, in situ Raman spectrum, and galvanostatic intermittent titration technique. More importantly, u-Sn@NCNTs can be used as the anode for potassium ion hybrid capacitors, achieving a superior energy density of 181.4 W h kg-1 at a power density of 185 W kg-1 with excellent cycling capability. This work could push forward the development and application of carbonaceous-based anode materials for next-generation high-performance rechargeable batteries.

Handedness Inversion of Chiral 3‐Aminophenol Formaldehyde Resin Nanotubes Mediated by Metal Coordination

AbstractPrecise adjustment of microstructure and handedness of chiral nanomaterials is important to regulate their properties and performance. Herein, helical 3‐aminophenol formaldehyde resin (APF) nanotubes and corresponding carbonaceous nanotubes with controllable handedness and optical activity were obtained via an external metal ion‐mediated supramolecular co‐templating method in an enantiomerically pure template system, in which an appropriate amount of Mn2+ (Co2+ or Ni2+) with moderate coordination abilities can reverse the spatial arrangement of the phenylglycine‐based amphiphilic template molecules through metal coordination. Different stacking modes of coordination complexes in disparate metal ion systems lead to diverse helical senses (diameter and pitch) of the obtained helical APF. In addition, this coordination mode of metal intervention can be applied to other amine‐based helical polymer synthesis systems, which paves the way for the design of high‐quality chiral nanomaterials with satisfactory physical parameters and properties.

Nitrogen-doped braided-looking mesoporous carbonaceous nanotubes as an advanced oxygen reduction electrocatalyst

Exploring low-cost, high-active, durable electrocatalysts for oxygen reduction reaction (ORR) in fuel cells and metal-air batteries is highly desirable but remains a great challenge. In this work, with the application of a newly developed metal-free nanocasting method, an in-situ mesoporous nitrogen-doped braided-looking carbon nanotube (MNCNT) catalyst was fabricated. It was examined to possess a high specific surface area (828 m2g-1), and pores with the tunable size. The catalyst shows superb ORR activity with a half-wave potential (E1/2) of 0.77 V vs. RHE in alkaline medium, inferior to that of commercial 20 wt% Pt/C, but superior to those of 5 wt% Pt/C and most other metal-free catalysts reported in previous literature. Besides, a high limited current density of 3.9 mA cm−2 at 0.2 V vs. RHE is yielded, and strong methanol tolerance as well as good stability of such catalyst is observed. According to the comparable study, the high ORR activity can be attributed to the porous feature of such nanotubes, as it may engender more active sites for ORR (porous nature & more edges), and boost reactivity of the active sites (nitrogen-doping), compared with the general carbon nanotubes. This work may intrigue the inspiration to explore highly efficient metal-free and carbon-based electrocatalysts toward boosting ORR.

Carbonaceous halloysite nanotubes for the stabilization of Co, Ni, Cu and Zn in river sediments

The remediation of heavy metal contaminated sediments has become a global consideration, especially the development of economically and environmentally efficient amendments.

Construction of 3D carbon networks with well-dispersed SiO x nanodomains from gelable building blocks for lithium-ion batteries.

Nonstoichiometric silicon oxide (SiOx) with high theoretical capacity is a promising anode material for lithium-ion batteries (LIBs). However, volume changes and poor electronic conductivity of SiOx are major impediments to its practical application. The modification of SiOx with carbonaceous materials to accommodate volume variations and improve conductivity is a valuable strategy. Nanonetwork-structured (NNS) carbons have been paid great attention because of their unique three-dimensional structure, and high electronic and ionic conductivity. Incorporating SiOx with well-designed NNS carbons is a promising method to prepare high quality electrode materials for lithium-ion batteries. In this work, a fabrication approach is developed to synthesize a 3D carbon network composed of carbonaceous hybrid nanotubes with well-dispersed SiOx nanodomains (CNT@SiOx–C) from 1D gelable bottlebrushes as network building blocks based on molecular-scale interface engineering technology. Herein, nano-sized SiOx particles are embedded into the carbonaceous matrix to prevent their volume change during cycling. The experimental results indicated that the CNT@SiOx–C presents high reversible capacity, remarkable cycle life and high rate capability due to the high dispersion of nano-sized SiOx and conductive 3D carbon nanonetwork.

Berichtigung: Cobalt–Nitrogen‐Doped Helical Carbonaceous Nanotubes as a Class of Efficient Electrocatalysts for the Oxygen Reduction Reaction

In dieser Zuschrift wurde eine falsche E-Mail-Adresse für Prof. Rui Cao angegeben. Die korrekte E-Mail-Adresse lautet: ruicao@ruc.edu.cn Die Autoren bitten, diesen Fehler zu entschuldigen.

Fabrication of Carbonaceous Nanotubes and Mesoporous Nanofibers as Stable Anode Materials for Lithium-Ion Battery

The morphologies and pore architectures of carbon nanostructures could be precisely controlled via a self-assembly process. This work presented resorcinol-formaldehyde resin-silica composite nanofibers, which were synthesized through a sol–gel method under the help of costructure directing agent (CSDA) (S)-β-citronellol and n-hexanol. The self-assembly process and the nanostructure of obtained composite nanofibers were changed by adding different CSDA. After carbonization and getting rid of silica, carbonaceous nanotubes and mesoporous nanofibers were obtained, respectively. Their electrochemical performance was tested as anode materials for lithium-ion batteries (LIBs). Stable discharge capacities of 574.3 mA h g–1 for carbonaceous nanotubes and 609.9 mA h g–1 for mesoporous carbonaceous nanofibers after 300 cycles were achieved at current density of 0.1 A g–1. Thus, a facile method of designing and fabricating excellent carbon anode candidates for LIBs was provided.

Cobalt–Nitrogen‐Doped Helical Carbonaceous Nanotubes as a Class of Efficient Electrocatalysts for the Oxygen Reduction Reaction

AbstractThe oxygen reduction reaction (ORR) is of significant importance in the development of fuel cells. Now, cobalt–nitrogen‐doped chiral carbonaceous nanotubes (l/d‐CCNTs‐Co) are presented as efficient electrocatalysts for ORR. The chiral template, N‐stearyl‐l/d‐glutamic acid, induces the self‐assembly of well‐arranged polypyrrole and the formation of ordered graphene carbon with helical structures at the molecular level after the pyrolysis process. Co was subsequently introduced through the post‐synthesis method. The obtained l/d‐CCNTs‐Co exhibits superior ORR performance, including long‐term stability and better methanol tolerance compared to achiral Co‐doped carbon materials and commercial Pt/C. DFT calculations demonstrate that the charges on the twisted surface of l/d‐CCNTs are widely separated; as a result the Co atoms are more exposed on the chiral CCNTs. This work gives us a new understanding of the effects of helical structures in electrocatalysis.

Cobalt–Nitrogen‐Doped Helical Carbonaceous Nanotubes as a Class of Efficient Electrocatalysts for the Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) is of significant importance in the development of fuel cells. Now, cobalt-nitrogen-doped chiral carbonaceous nanotubes (l/d-CCNTs-Co) are presented as efficient electrocatalysts for ORR. The chiral template, N-stearyl-l/d-glutamic acid, induces the self-assembly of well-arranged polypyrrole and the formation of ordered graphene carbon with helical structures at the molecular level after the pyrolysis process. Co was subsequently introduced through the post-synthesis method. The obtained l/d-CCNTs-Co exhibits superior ORR performance, including long-term stability and better methanol tolerance compared to achiral Co-doped carbon materials and commercial Pt/C. DFT calculations demonstrate that the charges on the twisted surface of l/d-CCNTs are widely separated; as a result the Co atoms are more exposed on the chiral CCNTs. This work gives us a new understanding of the effects of helical structures in electrocatalysis.

Nitrogen doped chiral carbonaceous nanotube for ultrasensitive DNA direct electrochemistry, DNA hybridization and damage study

In the interest of developing novel electrocatalyst for high performance DNA biosensing, with distinctive chiral double helix nanostructure, nitrogen doped chiral carbonaceous nanotube (Chiral-CNT) was employed for ultrasensitive label-free DNA biosensing research. Chiral-CNT can quantitative detection of four DNA bases with high sensitivity and selectivity. Without any prehydrolysis and labeling process, direct electrochemistry of single-stranded DNA and double-stranded DNA, qualitative and quantitative detection of DNA hybridization (low detection limit: 0.0268 g L−1) were realized. Moreover, sensitive detection of DNA damage induced by fenton reagent was also realized with low detection limit of 0.0350 mg mL−1 and high sensitivity of 7.42 μA mg−1 mL. The high biosensing performance attributes to the unique chiral structure of Chiral-CNT, leads to efficient interreaction between Chiral-CNT and DNA molecule.

Nitrogen-doped hierarchically porous carbonaceous nanotubes for lithium ion batteries

By a novel two-step activation of the polypyrrole nanotube (PPyNT) precursor, nitrogen-doped hierarchically porous carbonaceous nanotubes (HPCNT) are successfully prepared. The as-prepared HPCNT not only exhibits an ultrahigh specific surface area of 2180 m2 g−1 and a large total pore volume of 1.22 cm3 g−1, but also possesses a rich N-doping content of 8.2 wt% which especially includes a high pyridinic-N content of 30%. As an anode for lithium-ion batteries (LIBs), the HPCNT delivers an ultrahigh reversible capacity of 1372 mAh g−1 and keeps a high retention of 89.3% over 100 cycles at 0.1 A g−1. Even at a large current rate of 1 A g−1, the reversible capacity is still as high as 630 mAh g−1 after 700 cycles. Compared with either the commercial graphite or the state-of-the-art LIB carbons in the literature, the HPCNT is quite competitive, which makes it a promising anode material for next-generation LIBs. Also, the outstanding performances of the HPCNT exhibit a great potential of this novel activation strategy for commercial application on LIBs.

Energy Storage: Confined Assembly of Hollow Carbon Spheres in Carbonaceous Nanotube: A Spheres‐in‐Tube Carbon Nanostructure with Hierarchical Porosity for High‐Performance Supercapacitor (Small 19/2018)

Energy Storage: Confined Assembly of Hollow Carbon Spheres in Carbonaceous Nanotube: A Spheres‐in‐Tube Carbon Nanostructure with Hierarchical Porosity for High‐Performance Supercapacitor (Small 19/2018)

Oxygen-doped carbonaceous polypyrrole nanotubes-supported Ag nanoparticle as electrocatalyst for oxygen reduction reaction in alkaline solution

Developing low-cost and high-performance non-precious metal oxygen reduction reaction (ORR) catalysts for fuel cells is highly desirable but still full of challenges. In this work, oxygen-doped carbonaceous polypyrrole nanotubes (OCPN) are synthesized by a KOH-activated assisted method and Ag nanoparticles are grown in situ on OCPN. The resultant Ag/OCPN catalysts possess comparable excellent activity with commercial Pt/C (onset potential is −0.003 V vs. SCE) in alkaline solution, which is ascribed to the synergistic effect of Ag nanoparticles and the unique properties of OCPN. The best ORR property of Ag/OCPN demonstrated that the oxygen in the catalyst can facilitate the ORR. Moreover, superior stability and methanol tolerance deserve to be mentioned.

Confined Assembly of Hollow Carbon Spheres in Carbonaceous Nanotube: A Spheres-in-Tube Carbon Nanostructure with Hierarchical Porosity for High-Performance Supercapacitor.

Carbonaceous nanotubes (CTs) represent one of the most popular and effective carbon electrode materials for supercapacitors, but the electrochemistry performance of CTs is largely limited by their relatively low specific surface area, insufficient usage of intratube cavity, low content of heteroatom, and poor porosity. An emerging strategy for circumventing these issues is to design novel porous CT-based nanostructures. Herein, a spheres-in-tube nanostructure with hierarchical porosity is successfully engineered, by encapsulating heteroatom-doping hollow carbon spheres into one carbonaceous nanotube (HCSs@CT). This intriguing nanoarchitecture integrates the merits of large specific surface area, good porosity, and high content of heteroatoms, which synergistically facilitates the transportation and exchange of ions and electrons. Accordingly, the as-prepared HCSs@CTs possess outstanding performances as electrode materials of supercapacitors, including superior capacitance to that of CTs, HCSs, and their mixtures, coupled with excellent cycling life, demonstrating great potential for applications in energy storage.

Using carbonaceous nanoparticles as surfactant carrier in enhanced oil recovery: A laboratory study

Carbonaceous nanoparticles multi-walled carbon nanotubes (MWNTs) and carbon blacks (CBs) exhibit promising properties for potential applications in crude oil production. The combination of large specific surface area and the strong affinity toward surfactants of nanoparticles mark their candidacy for delivering surfactant deep inside the reservoir. This study is aimed to assess the feasibility of surfactant carriers in tertiary oil recovery. Stable dispersions of aqueous-phase MWNTs or CBs that are formulated and able to propagate through the reservoir medium (3 wt% brine and 60 °C) were first examined as a prerequisite for reservoir application. Competitive adsorption of surfactant on nanoparticles was beneficial to decrease adsorptive loss on Ottawa sand at equilibrium concentration below critical micelle concentration (CMC). As a proof of concept, phase behavior of a ternary surfactant microemulsion system confirmed that the chosen nanoparticles (100 mg/L) successfully delivered surfactants and spontaneously released them to the O/W interface. The observed phenomenon is in accordance with calculation of the Gibbs free energy associated with oil/water/surfactant system. Besides, surfactants carried by nanoparticles achieved equilibrium ultralow interfacial tension between excess oil and aqueous phase similar to the value of surfactant-only formulation (0.007–0.009 mN/m). In one-dimensional sand pack tests, injection of MWNT-surfactant blend achieved faster and higher tertiary recovery than surfactant-only formulation, with cumulative tertiary oil recovery of 42.7% versus 38.1%. It has been noticed that once surfactant been released, destabilization of nanoparticle dispersion occurred and thus increased their retention in porous medium. In case of tight formations, further improvements may be addressed by applying functionalized carbonaceous nanoparticles to assure their transport in porous media after release of surfactant.