Carbon Letters最新文献

Military tents are crucial for military operations. Existing military tents use insulating and photonically inert textiles, which cannot be used as electric or light-driven heaters, significantly restricting their application in high-altitude combat zones. Considering the simultaneous threats of rain, snow, electromagnetic radiation and bullet impact in the battlefield, a kind of multifunctional protective material is necessary for military tents. In this paper, a multifunctional material including MXene as the functional layer, nylon fabric as the base material, and room temperature vulcanized silicone rubber as the surface waterproof layer is developed. The results show that: Results show that the synergistic effect of MXene and silicone rubber modifies the surface roughness and surface energy of pure nylon fabric, increasing its hydrophobic contact angle from 38.3° to 105.3°. MXene can form continuous conductive networks on fabric surfaces at varying concentrations. The electromagnetic shielding effectiveness of MXene and silicone rubber modified nylon (MS-Nylon) in the X-band spectrum increases to 17.64 dB to 18.54 dB when the mass fraction of MXene reaches 18.87%. Concurrently, the fabric's photothermal performance was significantly enhanced. Comparing with Nylon without photothermal property, the surface temperature of MS-Nylon reached 42.29 °C after exposure to sunlight (illuminance of 88.5 × 10³ LUX). Following exposure to incandescent (200 W) and infrared (375 W) lamps, MS-Nylon temperatures reached 49.45 °C and 90.00 °C respectively. Notably, nylon's inherent mechanical and bulletproof properties remained nearly unchanged. This work provides valuable insights for the design of next generation multifunctional protective equipment.

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Coal gasification slag (CGS), a byproduct of coal chemical processes, can be repurposed as functional materials through acid treatment to remove impurities such as Al, Ca, and Fe.This study investigates the acid-leaching behavior of these impurities by examining the slag’s mineralogical structure and elemental distribution. The process involved initial carbon-ash separation via physical sieving (0.85 mm), yielding a low-carbon slag (L-CS) with < 3% carbon content and a 48.33% yield, characterized by dense, lamellar aluminosilicate glass with uniformly dispersed and encapsulated Ca and Fe. The L-CS was subjected to heat treatment at varying temperatures, followed by hydrochloric acid leaching. Results revealed that heat treatment broke and rearranged the original Si-O-Si(Al) bonds, partially converting [AlO4] structural units into more stable [AlO6] and leading to the sequential formation of magnetite and esseneite phases. This structural reorganization significantly reduced the leaching rates of Al, Ca, and Fe. Kinetic analysis demonstrated that the leaching of Fe and Ca was governed by a combination of internal diffusion and interfacial chemical reactions, whereas Al leaching was controlled solely by interfacial reactions. The Ca and Fe components were leached more readily than Al. Under optimized conditions (70 °C, 180 min, 8% HCl, liquid-to-solid ratio 8:1), the leaching rates reached 74.17% for Al, 90.01% for Ca, and 83.34% for Fe. The acid-leached residue primarily retained amorphous aluminosilicate phases with minor quartz, exhibiting a more ordered structure than the precursor. Morphologically, the original dense structure was disrupted, forming fractured surfaces composed of 40–60 nm nanospheres. The residue possessed a specific surface area of 101.44 m²/g and an average pore diameter of 5.734 nm. These findings indicate that the acid-leached CGS residue has significant potential for direct application as a mesoporous adsorbent material or for uses requiring enhanced reactivity.

Sensing toxic gas molecules is crucial for environmental monitoring and human safety. In this spin-polarized DFT study, we introduce BCN nanocage, a hybrid analogue of C₂₀ nanocage, for sensing Cl₂, COCl₂, H₂S, and NH₃ gas molecules. BCN is functionalized with a series of metal adatoms (Li, Be, Al, Si, P, Sc, Ti, V, Mn, Fe, Ni, and Cu), chosen for their diverse electronic configurations and potential to interact strongly with the substrate. Among these, only the Li-, Al-, Sc-, Fe-, and Cu-decorated BCN complexes were found to be thermodynamically stable and energetically favourable. Sc exhibits the strongest binding with the nanocage, followed by Fe, Al, Li, and Cu, due to bond formation and significant charge transfer from adatoms to the nanocage. Among the studied candidates, BCNCu emerges as the most promising for Cl₂ sensing under dry conditions, exhibiting an adsorption energy of 0.66 eV, a recovery time of 0.02s, and a -37.16% band gap variation. Compared with previously reported nanocage-based sensors, BCNCu demonstrates a balanced combination of suitable adsorption energy, rapid recovery time, and appreciable sensitivity, highlighting its potential for efficient Cl₂ detection under dry conditions. However, its sensing performance is influenced by humidity, indicating that BCNCu operates more effectively under dry conditions than in humid atmospheres. AIMD simulations and vibrational spectra analysis confirm the thermal stability of the substrate at 400 K and its dynamical stability. This study advances the field by establishing BCNCu as a promising Cl₂ sensor while highlighting its limitations in humid environments, offering valuable insights for experimental fabrication and real-world applications.

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We investigate the electronic structure and quantum transport of OPG-Z carbon nanoribbons using first-principles density functional theory (DFT) and non-equilibrium Green’s function (NEGF) methods. We find that cutting the OPG-Z lattice along different directions produces ribbon families with dramatically different behavior. One ribbon (armchair-PO motif) is essentially metallic, whereas others are semiconducting with giant electronic anisotropy: band gaps range from ~ 0.07 to 0.53 eV depending on the edge motif. This leads to highly direction-dependent conduction, with the metallic ribbon exhibiting orders-of-magnitude higher low-bias conductance than the narrow-gap ribbons. Transport simulations show that semiconducting OPG-Z nanoribbons require threshold biases comparable to their bandgap (~ 0.1–0.5 V) before significant current flows, whereas the metallic ribbon conducts readily at zero bias. Analysis of structure–property trends reveals that subtle changes in the fused pentagon–octagon edge motifs tune the effective bandgap and carrier transport. These pronounced anisotropic transport properties combined with the robust stability of the carbon lattice suggest OPG-Z nanoribbons as promising building blocks for future nanoelectronic and directional transport devices, such as anisotropic field-effect transistors and current rectifiers.

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Heteroatom nitrogen-doped defect engineering is considered an effective strategy for enhancing the microwave absorption performance of carbon-based hybrid materials. The focus of present work is to study the electromagnetic absorption properties of as-prepared Co_0.1Ni_0.4Zn_0.5Fe₂O₄/NrGO/MWCNT (CNZF/NrGO/MWCNT) nanocomposites that could be facilely modulated by changing the doping nitrogen contents to create the defect-induced polarisations which can be utilised as a promising candidates for microwave absorption materials (MAMs) for high-frequencies. Moreover, CNZF/NrGO/MWCNT nanocomposites are designed using a facile one-pot solvothermal method by varying nitrogen-doped content and configuration. It was found that the optimisation between pyrrolic-N and graphitic-N, rather than total nitrogen content unlike earlier reports, plays a decisive role in regulating the electron magnetic properties. The micromorphological analysis reveals the presence of interfacial defects within the as-prepared samples, which are beneficial for electromagnetic attenuation. The optimally nitrogen-doped CNZF/NrGO/MWCNT composite (S2), prepared using ethylenediamine (EDA=2 ml), exhibits the balanced dielectric magnetic loss behaviour and enhanced interfacial polarisation, exhibited superior microwave absorption performance, achieving a minimum reflection loss (RL_min) of -56.39 dB at 13.05 GHz with a thickness of 1.5 mm and a maximum effective absorption bandwidth (EAB_max) of 4.21 GHz in Ku band. Thus, this work provides a scalable and cost-effective method through defect engineering for designing an efficient MAMs for high-frequency applications.

The construction of an electrocatalytic NO₃⁻ reduction and polyacrylamide (HPAM) oxidation coupled reaction system represents a promising approach for simultaneously achieving ammonia synthesis and HPAM degradation. In this work, FeCo@N-CNTs with a well-defined heterojunction structure were successfully synthesized and employed as an efficient bifunctional electrocatalyst in the NO₃⁻ reduction and HPAM oxidation coupled reaction. In the coupled reaction system, The FeCo@N-CNTs catalyst delivered a maximum ammonia yield rate and Faradaic efficiency of 6097.96 ± 15.83 µg h^− 1 mg_cat⁻¹ and 92.03 ± 1.48%, respectively, while achieving an HPAM degradation rate of 89.99 ± 0.37% within 2 h. In-situ ATR-SEIRAS and in-situ DEMS analyses identified *NHOH as a key intermediate during the ammonia synthesis process and revealed that the heterojunction structure effectively regulates charge distribution and active-site exposure on the catalyst surface. This study offers a new strategy for designing coupled electrochemical systems toward efficient NO₃⁻ reduction and organic pollutant oxidation, providing valuable insights for sustainable nitrogen-cycle conversion and wastewater treatment.

Crystallinity has long been regarded as the hallmark of carbon fiber thermal stability; however, our findings reveal that increased structural order does not invariably translate to enhanced thermal resistance. In this study, we graphitized PAN-based carbon fibers up to 2700 °C and performed a comprehensive multiscale analysis of their structure and oxidation behavior, challenging the conventional assumption that greater crystallinity guarantees better thermal stability. Heat treatment did improve the graphitic alignment, microvoid evolution, and tensile modulus across all samples. Yet under oxidative conditions, a surprising reversal was observed: among T300B, T700S, and T800H, the least graphitized fiber (T300B) exhibited the highest thermal resistance, outperforming its high-modulus counterparts. This unexpected behavior is attributed to a dual mechanism: once thermal conductivity exceeds a critical threshold it accelerates oxidative degradation, while pronounced radial heterogeneity (skin–core transition zones) in the fiber structure impedes heat and oxygen penetration. These findings reshape the design paradigm for high-performance carbon fibers. They suggest that maximizing crystallinity alone is insufficient; instead, controlling thermal transport properties and internal structural gradients in tandem is crucial for engineering fibers capable of withstanding extreme oxidative environments.

The electronic and phonon transport properties of MoS₂ were tailored by fabricating MoS₂/MWCNT nanocomposites via a hydrothermal route. Incorporation of MWCNT resulted in a 58% enhancement in electrical conductivity, reaching 327 Sm^− 1 at 503 K, attributed to strong π-π interactions, reduced hopping energy of 0.228 eV and Fermi level shift toward the valence band. The MWCNT also acted as effective phonon scattering centres, reducing the thermal conductivity to 0.499 Wm^− 1K^− 1 at 453 K. HRTEM analysis revealed defects such as grain boundaries, dislocations and interfaces between 1D-MWCNT and 2D-MoS₂, which further promoted phonon scattering. Raman spectroscopy confirmed a reduction in Debye temperature and average sound velocity, indicating lattice softening. Overall, the incorporation of MWCNT in MoS₂ not only facilitates carrier transport by serving as conductive bridges between MoS₂ layers but also enhances phonon scattering, thereby optimizing thermoelectric performance.

Single−atom catalysts (SACs) have attracted significant attention in the field of electrocatalytic energy conversion owing to their unique catalytic properties and exceptionally high metal−atom utilization efficiency. This review systematically summarizes recent synthesis strategies for SACs, and critically analyzes the advantages and limitations of each approach. With respect to catalyst characterization, advanced techniques, such as aberration−corrected scanning transmission electron microscopy (AC−STEM) and X − ray absorption fine structure (XAFS), are highlighted for their crucial roles in elucidating atomic dispersion, coordination environments and electronic structures. Furthermore, the performance and applications of SACs in key electrocatalytic reactions are comprehensively reviewed, including the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and other representative reactions. Finally, current challenges and future research directions are discussed, offering insights into the reasonable design of high−performance SACs and their progress towards practical applications.

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This review comprehensively analyzes diverse synthesis strategies and characterization techniques for SACs and outlines their applications in key electrocatalytic reactions, with the aim of providing valuable insights for rationally designing high−performance SACs and accelerating their transition to practical use.