Nitrogen-containing Carbon Research Articles

Nitrogen-Containing Bisphosphonate Carbon Dots with High Affinity to Calcium-Based Biomaterials for Suppression of Osteoclasts

Nitrogen-Containing Bisphosphonate Carbon Dots with High Affinity to Calcium-Based Biomaterials for Suppression of Osteoclasts

All-in-one photothermal/catalytic flexible membrane for highly efficient desalination and organic pollutant degradation.

Interfacial solar vapor generation (ISVG) accompanied by photocatalytic degradation holds immense potential to mitigate water scarcity and pollution. Distinct from the two detached functional components (photothermal agent and photocatalyst) in a conventional evaporator, in this study, an all-in-one photothermal/catalytic agent, nitrogen-containing honeycomb carbon nanosheets (NHC), was engineered for synergistic high-efficiency steam generation and photocatalysis functions. It was demonstrated that the superoxide radical generated on the surface of NHC conferred its catalytic activity to the photodegradation of organic pollutants under full solar spectrum irradiation. A proof-of-concept multifunctional evaporator (called NHC@PEI/MCE), consisting of NHC grafted with polyethyleneimine (PEI) and a hydrophilic mixed cellulose ester membrane (MCE), was fabricated to achieve both solar-driven desalination and organic pollutant degradation. Owing to its excellent light absorption capability (∼96%), reduced evaporation enthalpy (1358 J g-1) and minimized heat loss (8.8%), the bi-layered evaporator performed a rapid water evaporation rate of 1.66 kg m-2 h-1 under one standard sun illumination. Notably, the edge-preferential crystallization strategy enabled the bi-layered evaporator to maintain long-term stability for continuous water evaporation and salt harvesting over 80 h in a concentrated 3.5 wt% NaCl solution. The design of the all-in-one photothermal/catalytic agent NHC ensured the synchronous removal of organic pollutants. The removal rates of methylene blue and phenol were 99.82% and 79.6%, respectively. Additionally, the reduction rate of total organic carbon (TOC) in the actual coking wastewater was found to be 96.6%. The exceptional purification capabilities across diverse water systems surpassed those of membrane materials lacking NHC. The exploration of the multifunctional evaporator offers a novel approach to achieving high-efficiency utilization of solar energy for the conversion of both seawater and industrial wastewater into freshwater.

Ethanol-induced ammonium polyphosphate-silver gel paint: breaking the trade-off between conductivity, flame retardancy and adhesion in single-layer functional coatings.

Electrical fires pose significant threats to the lives and property safety of people. Although utilizing coatings to impart conductivity and flame retardancy to materials is convenient and reliable, traditional layer-by-layer preparation methods have the limitations of cost, convenience and scalability. Therefore, a single-layer coating that simultaneously imparts excellent conductivity and flame retardancy to materials presents broader application prospects. And good adhesion of the coating is another essential aspect. However, the trade-off between conductivity, flame retardancy, and adhesion creates huge challenges in the development of such coatings. Here, we report an ethanol-induced ammonium polyphosphate-silver (APP-Ag) gel paint to completely address the above issues. High molecular weight APP served as both a flame retardant and an adhesive, while the coordinating action of phosphate groups ensured the effective dispersion of nanosilver, and the nitrogen-containing carbon layer formed from triethanolamine and ascorbic acid at high temperature significantly enhanced the conductivity of the coating by connecting the silver nanoparticles. The coated materials could exhibit an electrical conductivity of over 200 S m-1, with the limiting oxygen index (LOI) exceeding 60%. Meanwhile, the peak heat release rate (PHRR) and total heat release (THR) decreased by more than 30% compared to those of the untreated materials. Additionally, we utilized this gel paint to fabricate electric heating fabrics, motion sensors, and fire alarm devices. Finally, we have thoroughly explored the potential mechanisms of conductivity, flame retardancy, and adhesion of the gel coatings.

Lithium-Rich Layered Oxide Cathode Materials Modified for Lithium-Ion Batteries by CoS of a 3D Rock Salt Structure Assisted by PVP.

The problem of rapid degradation of the operating voltage and discharge specific capacity of lithium-rich layered oxide (LRMs) cathode materials is a major constraint for their commercial application. In this paper, CoS coating with a 3D layered structure assisted by PVP is used to enhance the cycle life and rate performance of the LRMs material. The introduction of PVP has the following effects: (1) it reduces the solubility of CoS in the electrolyte solution and forms a stable CoS coating, and (2) it acts as a nitrogen-containing carbon matrix material and the heteroatomic dopant, and can provide more active sites to improve the conductivity of CoS. In addition, the CoS coating is capable of efficaciously reducing the direct contact area between electrolyte solution and the LRMs material and alleviating the occurrence of harmful interface reactions. The result of this study manifests that after the modification through CoS modification by PVP, the problem of the capacity decay is obviously solved. When the current density is 0.2 C, the highest specific capacity of 248.87 mAh g-1 can be provided. The capacity retention ratio of the LRMs@CoS material is 87.21% after 100 cycles, and the capacity decay is 0.3182 mAh g-1 (1.1534 mAh g-1 for the LRMs material) per cycle. When the current density is 1 C, the first discharge specific capacity of 220.91 mAh g-1 is achieved, which demonstrates outstanding electrochemical performance. This study has come up with a simple and practical mentality to realize the modification of cathode materials for high-performance lithium-ion batteries.

Facile synthesis of nitrogen-containing multiwalled carbon nanotubes as a worth metal-free electrocatalyst for hydrogen evolution reaction and semicarbazide oxidation

Studies of metal-free carbon nanostructures prove effective in energy and environmental applications due to their molecular tunability and vast chemical space. Herein, we synthesize nitrogen-containing multi-walled carbon nanotubes (N-MWCNTs) via. acid-catalysed incorporation of 3, 4-diaminopyridine into multi-walled carbon nanotubes (MWCNTs), and demonstrating their efficacy in electrocatalytic hydrogen evolution reaction (HER) and semicarbazide (SCB) oxidation for energy and environmental waste management, respectively. Successful synthesis is further confirmed by analysis techniques, i.e. Fourier transform infrared (FTIR) spectral analysis shows the diminishing OH frequency around 3250 cm−1 in MWCNTs after functionalization and the formation of an OC–NH bond in N-MWCNTs at 1710 cm−1. X-ray diffraction (XRD) confirms the incorporation of N-species, while Raman spectroscopic analysis indicates an increase in the ID/IG ratio MWCNTs (∼1) to N-MWCNTs (∼1.25), suggesting more defective sites in the N-MWCNTs nanocomposite. X-ray photoelectron spectroscopy (XPS) reveals peaks at 399.38, 400.49, and 402.05 eV, attributed to pyridinic-N, aromatic amide-N, and protonated amine groups, respectively. N₂ adsorption-desorption studies shows a high Brunauer-Emmett-Teller (BET) surface area for N-MWCNTs (119.22 m2/g) compared to MWCNTs (74.94 m2/g). Linear sweep voltammetry (LSV) profiles demonstrate enhanced activity of N-MWCNTs for both HER and SCB oxidation at an ultralow potential of E = −0.55 V vs RHE at 10 mA/cm2, with a lower Tafel slope of 108 mV.dec−1. Moreover, the electrochemical sensing studies indicates on N-MWCNTs were demonstrating an efficient electron transfer to SCB with the lower detection limit of 0.004 μmol. This work provides carbon-based metal-free electrocatalysts for energy harvesting and environmental management.

Designing a series of RE based carbon composites (RE=Tb, Gd, Ho, Lu, Nd, Sm, Yb, Eu, and Ce)-especially Tb-N-Cs for oxygen reduction enhancement

Iron and nitrogen co-doped carbon materials (Fe–N–Cs) have enormous application prospects in cathodic oxygen reduction reaction (ORR) as efficient electrode materials. However, their stability is of great importance, but is still limited by severe Fenton reaction due to the preferential reaction between Fe2+ and H2O2. This paper intends to rationally design a series of rare earth (RE) metals based carbon matrix anchoring RE centers directly converted from RE oxides and small nitrogen-containing carbon molecules by employing the molten-salts-assisted pyrolysis. A class of prepared RE based carbon (RE-N-Cs) catalysts surprisingly exhibits ORR activities comparable to that of Pt/C. The Tb–N–Cs sample with the best catalytic activity among them was characterized by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) and X-Ray Diffraction (XRD). The characterization results show the presence of Tb single-sites in carbon substrate, with Eonset of 1.06 V and Jd of 6.37 mA cm−2, exceeding those of the commercial Pt/C (Eonset = 0.96 V vs. RHE; Jd = 5.64 mA cm−2).

ZIF-8-derived carbon substrates embedded with atomically dispersed FeN2O2 active sites as bifunctional catalysts for electrochemical carbon dioxide and oxygen reduction

Transition metal assemblies on nitrogen-containing carbon substrates have promising applications as bifunctional electrocatalysts for electrochemical carbon dioxide reduction reaction (CO2RR) and oxygen reduction reaction (ORR). In this study, ZIF-8 with a rhombic dodecahedral morphology was grown from zinc nitrate and 2-methylimidazole feedstock. Then, a nitrogen-containing carbon substrate with a pore structure was formed after the release of Zn through high-temperature calcination. During the calcination process at 700°C, Fe atoms were physically adsorbed on the nitrogen-containing carbon substrate and ligated with N/O to form FeN2O2 reactive sites. For CO2RR, FeN2O2/NC exhibited excellent catalytic properties for converting CO2 to CO, achieving a high Faraday efficiency of 95.5 % at −0.7 V. Under alkaline conditions, it demonstrated ORR performance (E1/2 = 0.83 V) comparable with that of Pt/C (E1/2 = 0.82 V). This study not only presents an energy-efficient method for CO2RR but also provides new insights into highly active catalysts for ORR.

Carbon Dioxide Capture on Oxygen- and Nitrogen-Containing Carbon Quantum Dots.

To address global climate change challenges, an effective strategy involves capturing CO2 directly at its source using a sustainable, low-cost adsorbent. Carbon quantum dots (CQDs), derived from lignin, are employed to modify the internal surface of an activated carbon adsorbent, enabling selective adsorption based on electrostatic interactions. By manipulating charge distribution on CQDs through either doping (nitrogen) or functionalization (amine, carboxyl, or hydroxyl groups), the study confirms, through classical molecular dynamics simulations, the potential to adjust binding strength, adsorption capacity, and selectivity for CO2 over N2 and O2. For simulations with a single component gas, maximum selectivities of 3.6 and 6.7 are shown for CO2/N2 and CO2/O2, respectively, at 300 K. Simulations containing a wet flue gas indicate that the presence of water increases the CO2/N2 and CO2/O2 selectivities. The highest CO2/H2O selectivity obtained from a CQD/graphite system is 4.3. A comparison of graphite and lignin-based carbon composite (LBCC) substrates demonstrated that LBCC has enhanced adsorptive capacity. The roughness of the LBCC substrate prevents the diffusion of the CQD on the surface. This computational study takes another step toward identifying optimal CQD atomic architecture, dimensions, doping, and functionalization for a large-scale CQD/AC adsorbent solution for CO2 capture.

RETRACTED: Fe–Co co-doped 1D@2D carbon-based composite as an efficient catalyst for Zn-air batteries

A Fe-Co dual-metal co-doped nitrogen-containing carbon composite (FeCo-HNC) was prepared by adjusting the ratio of iron to cobalt as well as the pyrolysis temperature with the assistance of functionalized silica template. Fe1Co-HNC, which was made from 1D carbon nanotubes and 2D carbon nanosheets with a rich mesoporous structure, presented exceptional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activity. The ORR half-wave potential is 0.86 V (vs. reversible hydrogen electrode, RHE), and the OER overpotential is 0.76 V at 10 mA cm−2 with the Fe1Co-HNC catalyst, which can be applied to zinc-air batteries with superior performance. It is worth noting that the zinc-air batteries with Fe1Co-HNC-1000 as the cathodic catalyst achieved the highest power density of 94.9 mW cm−2 under a current density of 159.8 mA cm−2. This method provides a promising strategy for fabricating efficient transition metal-based carbon catalysts.

Exploring New Carbon Allotropes and Nanographenes on Surfaces

The quest for planar sp2-hybridized carbon allotropes other than graphene has stimulated substantial research efforts because of their predicted unique mechanical, electronic, and transport properties. However, the syntheses of these nonbenzenoid networks remain challenging due to the lack of reliable protocols for generating nonhexagonal rings. We have developed various on-surface synthesis strategies by which straight polymer chains are linked to form the nonbenzenoid carbon networks. In this way, we synthesized biphenylene network, a new carbon allotrope with 4-6-8-membered rings, which is metallic already at very small dimensions. Similarly, we generated phagraphene nanoribbons, which are based on 5-6-7-membered rings.Acenes are another interesting class of carbon materials that have fascinated chemists and physicists due to their potential for use in organic electronic applications. We show the synthesis of tridecacene (13ac) and pentadecacene (15ac), the longest acenes known to date, via multistep single-molecule manipulation of suitable precursor molecules on Au(111). We find antiferromagnetic open-shell ground state electron configurations for both acenes. 15ac shows a low-bias spin-excitation feature, indicating a singlet-triplet gap of around 124 meV. Investigation of 15ac complexes with up to 6 gold atoms suggest considerable multiradical contributions to the electronic ground state of 15ac.Altering the electronic and magnetic properties of carbon-based nanomaterials can also be achieved by doping with heteroatoms. We present an access to a variety of nitrogen-containing 0D and 1D carbon nanostructures including planar and curved cycloarenes with different cavities as well as N-doped graphene nanoribbons.

Stability of Nitrogen-Doped Activated Carbon as an Electrocatalyst for the Oxygen Reduction Reaction in Various Storage Media.

Besides outstanding catalytic performance, the stability of nitrogen-doped carbon materials during storage is equally crucial for practical applications. Therefore, we conducted the first investigation into the stability of highly nitrogen-doped activated carbon (AC-NC-T) obtained by modifying activated carbon with CO2/NH3 in different storage media (air, vacuum and N2). The results of the catalysis of the oxygen reduction reaction and the activation of peroxymonosulfate for degrading bisphenol A by AC-NC-T show that the catalytic activity of AC-NC-T stored in air decays most prominently, while the performance attenuated only marginally when stored in vacuum and N2. The results from N2 adsorption isotherms, Raman spectroscopy, elemental and X-ray photoelectron spectroscopy indicate that the decline in catalytic activity is due to the presence of oxygen in the environment, causing a decrease in absolute contents of pyridinic N (N-6) and graphitic nitrogen (N-Q). After being stored in an air atmosphere for 28 days, the absolute contents of N-6 and N-Q in AC-NC-950 decreased by 19.3% and 12.1%, respectively. However, when stored in a vacuum or N2, the reduction in both was less than 7%. This study demonstrates that reducing oxygen concentration during storage is crucial for preserving high catalytic activity of nitrogen-containing carbon materials.

Preparation of Ni0.6Cu0.4O/NC catalyst and its catalytic performance for hydrogen production from hydrolysis of ammonia borane

Ammonia borane (NH3BH3, AB) is an ideal feedstock with high hydrogen storage capacity. In this paper, nitrogen-containing carbon material (Ni0.6Cu0.4O/NC) catalyst was prepared by high-temperature carbonization of Ni/Cu-ZIF precursor under nitrogen atmosphere. The microstructure as well as the composition of the as-prepared catalyst were characterized. In addition, the catalytic performance of the catalyst was tested under reaction conditions. The results showed that the activation energy (Ea) for hydrolysis of AB over Ni0.6Cu0.4O/NC catalyst was 56.8 kJ/mol with TOF value as high as 1572.2 h–1. The hydrogen production could be approximated as a zero-order reaction with respect to the concentration of AB, and a one-order reaction with respect to the amount of catalyst. The catalyst still maintained good activity after ten cycles, indicating the good stability.

Structural and magnetic properties of nitrogen-doped carbon materials derived from an ionic liquid precursor

In this report, effects of pyrolysis conditions on the structure and magnetic properties of nitrogen-doped graphitic carbon materials prepared from 1-Buthyl-3-methyl imidazolium tricyano methanide ( [BMIm] [TCM]) ionic liquids(ILs) were investigated. It was found that nitrogen-containing graphitic carbon was formed under pyrolysis temperature of 400 °C or higher. Under the experimental conditions, the maximum nitrogen content of the obtained sample was C4N1.10 at a pyrolysis temperature of 400 °C and it was found that the nitrogen content in the obtained samples decreased with increasing pyrolysis temperature. Ferromagnetism was not observed in all the obtained samples to 2 K. From the value of the orbital diamagnetic susceptibility and XRD, it was found that the obtained sample had the structural characteristics of soft carbon.

Ultrasensitive electrochemical sensor for fenitrothion based on MIL-125 derived iron/titanium bimetallic oxides doped porous carbon composite

Fenitrothion (FT) is a common organophosphorus pesticide widely used in agricultural. Residues of fenitrothion in crops can adversely affect human health. In this work, modified MIL-125-Fe was prepared by changing the solvent ratios and further etching with iron nitrate, followed by high-temperature pyrolysis to obtain modified-TiO2/FeTiO3-doped nitrogen-containing carbon framework (m-TiO2/FeTiO3@NCF). The porous carbon material of m-TiO2/FeTiO3@NCF was used to modify the GCE to produce FT electrochemical sensor. Under optimized conditions, the sensor exhibited good detection performance for FT with a low LOD of 0.96 nM and a wide detection linear range of 1–9000 nM, and also exhibited good reproducibility (RSD = 2.08 %), repeatability (RSD = 1.09 %) and anti-interference performance. The sensor was successfully applied in real sample tests showing the recovery rates of 98.7 %–101.2 %. The present study provides a new idea for the rapid and accurate detection of FT.

Iron-nitrogen co-doped carbon nanospheres prepared by template-free melting salt-assisted pyrolysis as efficient and durable oxygen reduction catalysts

It is necessary to seek oxygen reduction reactions (ORRs) electrocatalyst that can replace commercial Pt/C for new energy conversion devices. Herein, we used molten salt-assisted pyrolysis to successfully convert small nitrogen-containing carbon molecules directly into iron-nitrogen codoped carbon nanospheres (Fe–N–Cs) without the need for external templates. Molten salts provide a solvo-like environment for the high-temperature pyrolysis of small carbon molecules and bulk oxides. Small molecules containing nitrogen and carbon are subjected to spatial domain-limiting effect, reducing volatilization in the calcination processes. Besides, the strong polarity provided by molten salts can not only dissolve bulk oxides but also prevent free metal atoms from gathering again to form particles or clusters. The synthesized Fe–N–Cs exhibit excellent ORR activity. The half wave potential (E1/2, 0.67 V vs. RHE) in acidic solution is almost equivalent to Pt/C. Furthermore, Fe–N–Cs have the ability to prevent methanol poisoning and its stability is strong.

Nitrogen-Containing Carbon Tubes Fabricated by Light Irradiation.

Cotton-core/polypyrrole (PPy)-sheath fibers (cotton/PPy fibers) were synthesized by aqueous chemical oxidative seeded polymerization and were utilized as precursors for nitrogen-containing carbon (NCC) tubes. Irradiation of the cotton/PPy fibers with a near-infrared (NIR) laser heated them to approximately 300 °C due to light-to-heat photothermal conversion by the PPy, and the cotton core was thermally decomposed and vaporized. Scanning electron microscopy studies revealed the formation of tubes with monodispersed diameters, and elemental microanalysis, Fourier transform infrared spectroscopy, and Raman spectroscopy confirmed that the PPy sheath was converted into NCC. Furthermore, sunlight also worked as the light source in fabricating the NCC tubes. The thicknesses of the tubes were controlled between 410 nm and 2.30 μm by tuning the PPy sheath thickness. The method developed in this study can be extended to other polymeric fibers, including acrylic and wool fibers. The shapes of the cross sections and surface nanomorphologies of the NCC tubes can be reflected in those of the polymer/PPy fibers.

Insight into the Role of NH3/NH4+ and NOx/NO3- in the Formation of Nitrogen-Containing Brown Carbon in Chinese Megacities.

Particulate brown carbon (BrC) plays a crucial role in the global radiative balance due to its ability to absorb light. However, the effect of molecular formation on the light absorption properties of BrC remains poorly understood. In this study, atmospheric BrC samples collected from six Chinese megacities in winter and summer were characterized through ultrahigh-performance liquid chromatography coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap MS) and light absorption measurements. The average values of BrC light absorption coefficient at a wavelength of 365 nm (babs365) in winter were approximately 4.0 times higher than those in summer. Nitrogen-containing organic molecules (CHNO) were identified as critical components of light-absorbing substances in both seasons, underscoring the importance of N-addition in BrC. These nitrogen-containing BrC chromophores were more closely related to nitro-containing compounds originating from biomass burning and nitrogen oxides (NOx)/nitrate (NO3-) reactions in winter. In summer, they were related to reduced N-containing compounds formed in ammonia (NH3)/ammonium (NH4+) reactions. The NH3/NH4+-mediated reactions contributed more to secondary BrC in summer than winter, particularly in southern cities. Compared with winter, the higher O/Cw, lower molecule conjugation indicator (double bond equivalent, DBE), and reduced BrC babs365 in summer suggest a possible bleaching mechanism during the oxidation process. These findings strengthen the connection between molecular composition and the light-absorbing properties of BrC, providing insights into the formation mechanisms of BrC chromophores across northern and southern Chinese cities in different seasons.

Polybenzoxazine-Based Nitrogen-Containing Porous Carbon and Their Composites with NiCo Bimetallic Oxides for Supercapacitor Applications.

Supercapacitors (SCs) are considered as emerging energy storage devices that bridge the gap between electrolytic capacitors and rechargeable batteries. However, due to their low energy density, their real-time usage is restricted. Hence, to enhance the energy density of SCs, we prepared hetero-atom-doped carbon along with bimetallic oxides at different calcination temperatures, viz., HC/NiCo@600, HC/NiCo@700, HC/NiCo@800 and HC/NiCo@900. The material produced at 800 °C (HC/NiCo@800) exhibits a hierarchical 3D flower-like morphology. The electrochemical measurement of the prepared materials was performed in a three-electrode system showing an enhanced specific capacitance for HC/NiCo@600 (Cs = 1515 F g-1) in 1 M KOH, at a current density of 1 A g-1, among others. An asymmetric SC device was also fabricated using HC/NiCo@800 as anode and HC as cathode (HC/NiCo@600//HC). The fabricated device had the ability to operate at a high voltage window (~1.6 V), exhibiting a specific capacitance of 142 F g-1 at a current density of 1 A g-1; power density of 743.11 W kg-1 and energy density of 49.93 Wh kg-1. Altogether, a simple strategy of hetero-atom doping and bimetallic inclusion into the carbon framework enhances the energy density of SCs.

Cross-polymerization between bio-oil and polyaniline: synergistic effects on pore development in subsequent activation and adsorption of phenol

The preparation of nitrogen-containing porous carbon by cross-polymerization of polyaniline and bio-oil during activation process for phenol adsorption.

Design of Fe and Cu bimetallic integration into nitrogen-containing microporous graphene-like carbon via a hard-template-assisted strategy as an oxygen reduction catalyst for Al–air batteries

The performance of the oxygen reduction reaction (ORR) can be enhanced through the utilization of multi-heteroatom doped, porous, and layered electrocatalysts.