Nitrogen-doped Amorphous Carbon Research Articles

Synthesis of nitrogen-doped amorphous carbon nanotubes from novel cobalt-based MOF precursors for improving potassium-ion storage capability

Amorphous carbon materials with sophisticated morphologies, variable carbon layer structures, abundant defects, and tunable porosities are favorable as anodes for potassium-ion batteries (PIBs). Synthesizing amorphous carbon materials typically involves the pyrolysis of carbonaceous precursors. Nonetheless, there is still a lack of studies focused on achieving multifaceted structural optimizations of amorphous carbon through precursor formulation. Herein, nitrogen-doped amorphous carbon nanotubes (NACNTs) are derived from a novel composite precursor of cobalt-based metal–organic framework (CMOF) and graphitic carbon nitride (g-CN). The addition of g-CN in the precursor optimizes the structure of amorphous carbon such as morphology, interlayer spacing, nitrogen doping, and porosity. As a result, NACNTs demonstrate significantly improved electrochemical performance. The specific capacities of NACNTs after cycling at current densities of 100 mA/g and 1000 mA/g increased by 194 % and 230 %, reaching 346.6 mAh/g and 211.8 mAh/g, respectively. Furthermore, the NACNTs anode is matched with an organic cathode for full-cell evaluation. The full-cell attains a high specific capacity of 106 mAh/gcathode at a current density of 100 mA/g, retaining 90.5 % of the specific capacity of the cathode half-cell. This study provides a valuable reference for multifaceted structural optimization of amorphous carbon to improve potassium-ion storage capability.

Sandwiched ReS2 nanocables with dual carbon coating for efficient K+/Na+ storage performance

In this work, the nanocables of few-layered ReS2 nanosheets sandwiched between carbon nanotubes (CNTs) and nitrogen-doped amorphous carbon (NC) coating (i.e., CNT@ReS2@NC) are synthesized as high-performance anodes of both potassium-ion batteries (PIBs) and sodium-ion batteries (SIBs). The CNT@ReS2@NC nanocables with dual carbon modifications have the several advantages for efficient K+/Na+ storage. The few-layered ReS2 nanosheets with a wide interlayer spacing of 0.64 nm contribute to accelerated reaction kinetics for fast K+/Na+ intercalation/extraction. The carbon nanotube skeleton with a hollow interior can effectively relieve the volume change and serve as a robust conductive network to boost structural stability. The NC layer provides rich defects as active sites and suppresses the shuttle effect of polysulfides produced in discharge/charge processes. Consequently, the CNT@ReS2@NC nanocables possess outstanding electrochemical performance in both PIBs and SIBs owing to the synergistic effect from the different components. A long cycling lifespan of 3500 cycles with a maintained discharge capacity of 125 mAh/g is achieved for CNT@ReS2@NC at 1 A/g in PIBs. In SIBs, it can keep a high capacity of 202 mAh/g over 3000 cycles at 5 A/g. Moreover, the CNT@ReS2@NC||Na3V2(PO4)3 full cell can exhibit remarkable cycling performance, yielding a low capacity decay rate of 0.019 % per cycle over 1000 cycles at 2C.

Recyclable fabrication of hollow N-doped amorphous carbon nanospindles with abundant short-range curved carbon fragments as bifunctional anode for lithium/sodium ion storage

A recyclable hard-template method is proposed to exploit spindle-shaped hollow nitrogen-doped amorphous carbon (h-NAC) with a large number of short-range curved carbon fragments as anodes for lithium/sodium ion batteries (LIBs/SIBs). Besides providing adsorption sites due to the high existence of oxygen-containing functional groups (CO and COOH), the heavily exposed edge regions also provide a favorable storage environment with high adsorption energy for Li+/Na+ due to their short-range curved structure. Importantly, the etching solution of hard templates can be recycled to generate the FeOOH nanospindles as a precursor through a simple chemical titration, which supplies a new idea for the green preparation of hollow materials. The h-NAC electrode is proven to be bifunctional for storing lithium and sodium ions, displaying favorable rate capability (255 mAh g−1 and 106 mAh g−1 at 5 A g−1 for LIBs and SIBs, respectively). After 1000 cycles at 1 A g−1, the reproducible capacities of the LIBs and SIBs kept 496 mAh g−1 and 181 mAh g−1, respectively.

Nitrogen-Doped Amorphous Carbon Homojunction from Palmyra Sugar as a Renewable Solar Cell

Nitrogen-Doped Amorphous Carbon Homojunction from Palmyra Sugar as a Renewable Solar Cell

TiO2 Nanoparticles Coated with Nitrogen-Doped Amorphous Carbon as Lubricant Additives in Engine Oil

TiO₂ Nanoparticles Coated with Nitrogen-Doped Amorphous Carbon as Lubricant Additives in Engine Oil

In-situ surface reconstructed NiOOH/Ni-ZnSe composite electrocatalysts with high activity toward oxygen evolution reaction in alkaline media

Fabricating long-durability and high-activity electrodes for oxygen evolution reaction (OER) in alkaline electrolyte is of great importance for practical water electrolysis. In this work, we develop a composite catalyst composed of Ni-doped zinc selenide nanoparticles embedded in nitrogen-doped amorphous carbon framework (denoted as Ni-ZnSe composite). Concretely, the systematic investigations disclose that the amorphous nickel (oxy)-hydroxide (NiOOH) in-situ formed on the surface of the hybrid catalyst during the OER process is considered as the genuine active centers. This self-reconstructed electrocatalyst (denoted as NiOOH/Ni-ZnSe) only demands small overpotentials of 218, 242 and 292 mV at the 10, 20 and 50 mA cm-2, respectively, as well as low Tafel slope of 56 mV dec-1 in alkaline media. XPS characterization reveals that performance enhancement is attributed to the electronic interaction between Ni-ZnSe and nitrogen-doped carbon (NC) that facilitate interfacial electron transfer, which in turn favors improve the oxygen evolution activity. This work not only enhances the electrocatalytic activity of selenide-based catalyst, but also provides a judicious avenue for developing advanced heterometallic doped catalysts toward OER and beyond.

Correction to: Dispersive solid phase extraction based on simply prepared nitrogen-doped amorphous carbon nanocomposite combined with dispersive liquid–liquid microextraction: application in the extraction of some pesticides from fruit juices

Correction to: Dispersive solid phase extraction based on simply prepared nitrogen-doped amorphous carbon nanocomposite combined with dispersive liquid–liquid microextraction: application in the extraction of some pesticides from fruit juices

Effect of N doping on the microstructure and dry etch properties of amorphous carbon deposited with a DC sputtering system.

The importance of developing a hardmask with excellent performance, and physical and chemical properties to utilize in long-term etching is spotlighted due to the acceleration of development in high-density semiconductors. To develop such a hardmask, amorphous carbon hardmasks doped with various concentrations of N were fabricated with a DC magnetron sputtering system using varying inert gas (Ar to N2) ratios. In contrast to the expectation that doped nitrogen would block the permeation of fluorine and improve the etch resistance, as the nitrogen concentration increased, the selectivity of the doped amorphous carbon films decreased. To understand this degradation with increasing nitrogen concentration, systematic X-ray photoelectron spectroscopy (XPS), radial distribution function (RDF), and X-ray reflectometry (XRR) analyses were conducted. In this study, we found that as the amount of nitrogen increased, the density of the film decreased, and the amount of pyridinic and pyrrolic nitrogen bonds with low formation energy increased. In contrast, based on time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis of etched nitrogen-doped amorphous carbon films, the penetration depth of fluorine ions from the etchant decreased as the amount of nitrogen increased. Therefore, in order to develop an excellent hardmask using amorphous carbon, it is important to increase the density of the film and the nitrogen concentration in the film while lowering the ratio of pyrrolic N to pyridinic N, i.e., increasing the ratio of graphitic N.

High energy density lithium-ion capacitor enabled by nitrogen-doped amorphous carbon linked hierarchically porous Co3O4 nanofibers anode and porous carbon polyhedron cathode

Lithium-ion capacitors (LICs) are emerging as progressive energy storage systems with high energy density, high power output, and a long cycle life span. The key to constructing LICs with high performances is alleviating the dynamics mismatch between the faradic anode and capacitor-type cathode. Herein, nitrogen-doped amorphous carbon linked hierarchically porous Co 3 O 4 nanofibers (NAC- l -Co 3 O 4 NFs) were prepared by electrospinning strategy, where the amorphous carbon can mitigation the volume variation of Co 3 O 4 during the lithiation/delithiation process, while the hierarchically porous structure provides effective channels and exposes more active sites for fast electron transfer and Li + storage. The delicate structure endows NAC- l -Co 3 O 4 NFs with remarkable rate capacity and robust cycling durability. Furthermore, nitrogen-doped carbon polyhedron (NPCP) is prepared for the cathode, displaying superior rate performances and cycling stability. As a result, by assembling the NAC- l -Co 3 O 4 //NPCP LICs, a high energy density of 296 Wh kg −1 and a high output of 11750 W kg −1 is delivered. Additionally, the LIC devices display excellent cycle lifespan (80% capacity retention after 10000 cycles at 1 A g −1 ). • Nitrogen-doped amorphous carbon-linked Co 3 O 4 1D nanostructured anode (NAC-l-Co 3 O 4 NFs) is fabricated via electrospinning technique. • The 1D nanofibers interlink into a 3D network further facilitating ions/electrons transmittability. • The LIC assembled with NAC- l -Co 3 O 4 anode shows an ultrahigh energy density (357 Wh kg) and excellent cycling stability.

Application of a microwave synthesized ultra-smooth a-C thin film for the reduction of dielectric/semiconductor interface trap states of an oxide thin film transistor

Improvement in TFT performance has been achieved by introducing a solution-processed ultra-smooth nitrogen-doped amorphous carbon (a-C) thin film in between gate dielectric and semiconductor.

Understanding the CO2/CH4/N2 Separation Performance of Nanoporous Amorphous N‐Doped Carbon Combined Hybrid Monte Carlo with Machine Learning

AbstractAmorphous carbon (aC) is widely used as the adsorbent in the purification of industrial gas. Introducing nitrogen dopant can regulate the morphology and improve the adsorption capacity of specific species. Due to the amorphous structure, it is difficult to understand the relationship between structural features and adsorption performance through atom‐based simulation. Here, a series of nitrogen‐doped amorphous carbon (N‐aC) models is built through reverse Monte Carlo method. The uptakes of three common gases, i.e., CO2, CH4, and N2 are estimated in each constructed framework by using grand canonical Monte Carlo (GCMC). Deep neural network is trained based on the simulated adsorption capacity with nitrogen content, surface area, pore size, atomic charge, and other factors. Through the data‐driven approaches, the adsorption capacity and the selectivity of three gases are predicted. The simulation in this study shows that the nitrogen content has less influence on the capacity and selectivity than the structural parameters, while nitrogen doping may improve CO2 loading and separation selectivity in the nanopores with pore size close to gas molecules. This work is helpful in constructing amorphous carbon structures for further simulation and understanding the influence of various features on gas separation.

Facile synthesis of N-C/Si@G nanocomposite as a high-performance anode material for Li-ion batteries

Nitrogen-doped carbon wrapped Si nanoparticles (NPs) hybridized with 3D graphene conductive network (N-C/Si@G) is developed as a novel nanocomposite for lithium-ion battery (LIB) anodes. The nanocomposite is synthesized via a facile technique that involves self-assembly of Si NPs (~50 nm) with graphene oxide (Si@GO) and formation of mixture of Si@GO and polyacrylonitrile (PAN) in the presence of dimethyl sulfoxide (DMSO), followed by a carbonization treatment under a temperature of 750 °C. Si NPs encapsulated in nitrogen-doped amorphous carbon shell are completely filled in a 3D graphene network. When employed as a LIB anode, N-C/Si@G was able to achieve a high specific capacity of 1750 mAh g−1 at a current density of 0.1 A g−1. In addition, the N-C/Si@G nanocomposite showed the excellent cyclic performance with a specific capacity of ~701 mAh g−1 at 5 A g−1 over 800 cycles. Based on the collective results, the enhanced electrochemical performance of N-C/Si@G nanocomposite might be largely ascribed to the synergistic effect arised from N-doped carbon shell and large void space of the 3D graphene network. Individually, N-doped carbon shell can help to enhance the overall electronic conductivity of the material, while the large void in 3D graphene network can provide enough space to accommodate the severe volume change of Si NPs.

Nitrogen-doped amorphous carbon coating on copper pads for direct wire bonding with a long-term humidity reliability

To improve the long-term reliability of copper (Cu) pads used in LSIs, nitrogen-doped amorphous carbon (a-C:N) coating is applied to the Cu pads with direct wire-bonding to prevent Cu oxidation in humidity. To obtain a thin barrier, the thickness optimization of a-C:N layer was carried out under temperature humidity storage (THS) testing at the conditions of 85 °C/85% relative humidity. Cu pad chains coated with the optimized a-C:N film were fabricated by direct bonding with aluminum (Al) wires. The electrical connection up to 210 bonds was obtained with the 10 and 15 nm thick a-C:N coated Cu pads. The reliability test of the pad-chains under the THS was carried out, and a 15 nm thick a-C:N can preserve the electrical connection along 100 h of the THS test. The a-C:N coating is expected to improve the humidity reliability of Cu pads with direct wire-bonding for long-term data storage.

Dispersive solid phase extraction based on simply prepared nitrogen-doped amorphous carbon nanocomposite combined with dispersive liquid–liquid microextraction: application in the extraction of some pesticides from fruit juices

In the present survey, a nitrogen-doped amorphous carbon nanocomposite has been prepared simply and eco-friendly from heating an acidic solution of sorbitol and urea. It was used as an efficient sorbent in dispersive solid phase extraction for the extraction of some pesticides (chlorpyrifos, diniconazole, clodinafop–propargyl, oxadiazon, fenpropathrin and penconazole) from fruit juice samples. The method was followed by a dispersive liquid–liquid microextraction procedure for more preconcentration of the analytes. The extracted analytes were determined by gas chromatography–flame ionization detection. Under optimized experimental conditions, relative standard deviations were in the ranges of 3–5% and 5–7% for intra-day (n = 6) and inter-day (n = 4) precisions, respectively, at a concentration of 10 μg L−1 for each analyte. The limits of detection and quantification were in the ranges of 0.89–1.3 and 3.0–4.3 μg L−1, respectively. The linear ranges were achieved in the range of 3.0–2000 μg L−1. Also, enrichment factors and extraction recoveries were obtained in the ranges of 380–455 and 76–91%, respectively. Finally, the developed approach was performed to determine the studied pesticide residues in various fruit juices including pomegranate, sour cherry, grape, orange and apple.

Use of nitrogen-doped amorphous carbon nanodots (N-CNDs) as a fluorometric paper-based sensor: a new approach for sensitive determination of lead(ii) at a trace level in highly ionic matrices.

This work reports a facile synthesis of nitrogen-doped amorphous carbon nanodots (N-CNDs) and their use as a fluorometric paper-based sensor for the determination of Pb2+ at a low concentration. Both solution-based and paper-based systems were developed. The results show that the linearity ranges for Pb2+ determination were 0.010-10 mg L-1 (LOD = 0.008 mg L-1) and 0.005-0.075 mg L-1 (LOD = 0.004 mg L-1) for the solution-based and the paper-based sensors, respectively. Furthermore, the developed sensors show relatively high selectivity toward Pb2+ over ten other metal cations of different charges including As3+, Hg2+, Cd2+, Mg2+, Ni2+, Zn2+, Fe3+, Cu2+, Ba2+, and Ag+. The mechanism of Pb2+ determination was also investigated. It was found that the sensors exploited the quenching of the fluorescence intensity of N-CNDs by Pb2+via the photo-induced electron transfer (PET) mechanism. When applied to real water and herbal medicine samples, the performance of the sensor exhibited no significant difference as compared to the results of the validation method (ICP-OES). Overall, the developed sensors, especially the paper-based one, are promising for the practical analysis of Pb2+ in pharmaceutical and environmental samples with a low Pb2+ concentration.

Room-Temperature Negative Differential Resistance in Amorphous Carbon: The Role of Electron Trapping Defects at Device Interfaces

Hysteresis and NDR have been observed in the room-temperature current–voltage characteristics of lateral devices featuring planar graphitic electrodes separated by a nitrogen-doped amorphous carbon (a-CN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> ) layer. The devices were fabricated using energetic physical vapor deposition and electron-beam lithography. Devices formed on a-CN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> layers deposited with N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> pressure of 0.10 mTorr exhibited NDR. This NDR occurred at a well-defined voltage/electric field but only after the voltage of the opposite polarity was applied. Based on this behavior, a model is proposed in which the NDR occurs by field-induced trapping/detrapping at one of the graphite/a-CN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> interfaces within the device. The results of this investigation highlight the importance of interfaces and defects in determining the characteristics of a-C memristive devices.

Structural Analysis of Boron- and Nitrogen-Doped Amorphous Carbon Films from Bio-Product

Amorphous carbon films have been explored and used in a wide variety of applications. With the n-type and p-type amorphous carbon film, it can be used to make p-n junctions for solar cells. This research aims to study the structure of boron- and nitrogen-doped amorphous carbon (a-C:B and a-C:N) films. This research uses the basic material of bio-product from palmyra sugar to form amorphous carbon. Amorphous carbon was synthesized by heating the palmyra sugar at 250°C. The results of XRD showed that the doped films produce an amorphous carbon phase. PES was used to analyze the bonding state of dopants in the sample. B4C, BC3, and BC2O bonds formed in a-C:B, while pyridine and pyrrolic formed in a-C:N.

Prussian blue analogs (PBA) derived porous bimetal (Mn, Fe) selenide with carbon nanotubes as anode materials for sodium and potassium ion batteries

The development of sodium/potassium-ion batteries with excellent performance would break the conflict between the limited lithium resources and low-price requirement of lithium-ion batteries. However, because of the bigger sizes of sodium/potassium ion in comparison to lithium ion, the requirement of anode materials with suitable structure for sodium/potassium ions insertion/extraction is still challenging. Here, porous MnSe/FeSe2 (Mn-Fe-Se) adhered/inserted with interlaced carbon nanotubes (CNTs) have been successfully designed and prepared via a simple chemical precipitation approach and a subsequent one-step carbonization-selenization of Mn-Fe Prussian blue analogs precursor process. Characterization results demonstrate that the prepared Mn-Fe-Se/CNTs with high conductive network architecture are constructed by Mn-Fe-Se sphere adhered/inserted with interlaced CNTs, each Mn-Fe-Se sphere is assembled using several tens of nanoparticles and numerous voids, and the individual nanoparticle is uniformly coated by a thin nitrogen-doped amorphous carbon layer. Due to such unique porous architecture and synergistic effect of the heterogeneous components, Mn-Fe-Se/CNTs anode possesses reversible sodium/potassium storage with excellent rate performance and prominent cycling stability. Furthermore, the sodium and potassium storage mechanisms and kinetics verify the fundamental principles of improved electrochemical performance. This study will shed light on the development of other metal selenides with interlaced carbon nanotubes for high-performance sodium/potassium-ion batteries and other energy storage equipment.

Construction of Single-Iron-Atom Nanocatalysts for Highly Efficient Catalytic Antibiotics.

Bacterial infection caused by pathogenic bacteria has long been an intractable issue that threatens human health. Herein, the fact that nanocatalysts with single iron atoms anchored in nitrogen-doped amorphous carbon (SAF NCs) can effectively induce peroxidase-like activities in the presence of H2 O2 , generating abundant hydroxyl radicals for highly effective bacterial elimination (e.g., Escherichia coli and Staphylococcus aureus), is reported. In combination with the intrinsic photothermal performance of the nanocatalysts, noticeable bacterial-killing effects are extensively investigated. Especially, the antibacterial mechanism of critical cell membrane destruction induced by SAF NCs is unveiled. Based on the bactericidal properties of SAF NCs, in vivo bacterial infections propagated at wounds by E. coli and S. aureus pathogens can be effectively eradicated, resulting in better wound healing. Collectively, the present study highlights the highly efficient in vitro antibacterial and in vivo anti-infection performances by the single-iron-atom-containing nanocatalysts.

Encapsulating Mo-Doped TiO2 Anatase in N-Doped Amorphous Carbon With Excellent Lithium Storage Performances

For improving the capability, cycling stability and rate capacity of anatase TiO2-based electrode, Mo-doped TiO2 anatase encapsulated in nitrogen-doped amorphous carbon (denoted for Mo-TiO2@NC) were synthesized through a facile hydrothermal method and followed by coating with polyaniline (PANI) and heating treatment. When tested as anode for lithium ion batteries, the Mo-TiO2@NC electrode showed initial discharge and charge capacities of 850.7 and 548.3 mAh g-1 at a current density of 85 mA g-1, respectively, with a remarkable discharge capacity maintained at 449.2 mAh g-1 after 100 cycles. Even at high current density of 850 mA g-1, a reversible capacity of 154 mAh g-1 after 200 cycles is obtained, displaying good rate capacity and long-term cycling stability. The outstanding electrochemical performance of Mo-TiO2@NC could be attributed to the synergistic effect of aliovalent ions doping and carbon coating.