Carbon Letters最新文献

Developing highly durable and active catalysts is essential for improving the performance and longevity of proton exchange membrane fuel cells (PEMFCs). In this study, we propose a novel strategy to enhance catalyst dispersion and stability by incorporating pyrrolic nitrogen-rich carbon (pNC) quantum dots into highly crystalline carbon supports. The introduction of pNC generates strong anchoring sites for Pt nanoparticles, facilitating uniform dispersion and minimizing aggregation, which are key factors in enhancing catalytic performance and durability. The synthesized Pt/CVC150 catalyst exhibited excellent oxygen reduction reaction activity, with a half-wave potential of 0.842 V and a limiting current density of 6.3 mA cm⁻². Under accelerated stress test conditions, the catalyst retained 61.4% of its initial peak power density after prolonged cycling, indicating enhanced durability. Furthermore, single cell testing confirmed its improved electrochemical activity and stability of the Pt/CVC150 catalyst in a practical PEMFC operating environment. These findings suggest that the incorporation of heteroatom-doped carbon moieties onto carbon supports represents a promising strategy for the development of next-generation PEMFC catalysts with enhanced performance and longevity.

Presently, the majority of cancer treatments are non-specific, leading to undesirable side effects from intense medications. This issue may be addressed through the revolutionary advancement of nanotechnology, which enables the control of materials at the nanoscale. By offering advantages such as customized drug delivery, minimized dose-associated side effects, and extended drug circulation times, nanotechnology has significantly impacted cancer therapy over recent decades. Due to their unique combination of superior optical, thermal, electrical, and mechanical properties, carbon-based nanoparticles are emerging as promising tools in cancer research. These nanoparticles also offer ease of modification and a large surface area, making them ideal for efficient drug delivery. These nanoplatforms can serve as carriers for multiple types of molecules, enabling targeted and controlled delivery of pharmaceuticals, nucleotides, and diagnostic agents. The synthesis techniques and functionalization approaches of carbon-based nanostructures, both covalently and noncovalently bound, will be explored in detail within this review. In addition, the properties of carbon nanostructures, their potential for delivering anticancer drugs and genetic material, as well as their antibacterial capabilities, will be analyzed. Lastly, the challenges associated with utilizing carbon nanostructures and future perspectives will be discussed.

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This study presents, for the first time, a piezoelectric nanogenerators (PENG) model based on the nitrogen-doped carbon nanotubes (N-CNTs) array and demonstrates the ability of N-CNT to convert external oscillations into electrical energy. Molybdenum was proved to be a preferred material for the upper electrode due to its high corrosion resistance and the formation of ohmic contact at the interface with N-CNT. It was shown the operation of the PENG model in constant and pulsed modes. It was found that the output voltage of the PENG model increased linearly from 3 to 60 mV with an increase in the amplitude of the external mechanical influence from 3.5 to 95 μm and decreased from 54 to 26 mV with an increase in the frequency of external influence from 15 to 120 Hz due to an excess of the natural resonant frequency of the nanotubes. The experiments demonstrated that the power density of the N-CNT-based PENG model reached 12.63 μV/cm². It was exhibited that the PENG model can be used not only as a nanogenerator for autonomous power supply of wearable electronic devices, but also as a highly sensitive deformation sensor. In addition, the clamping force of the upper electrode determines the frequency range of the PENG model. The obtained results open wide opportunities for practical application of vertically aligned N-CNTs for autonomous power supply of wearable electronic devices.

The constituents of coal tar pitch (CTP) significantly impact the wettability of calcined coke (CC) and the performance of prebaked anodes (PA) used in aluminum electrolysis. However, balancing wettability and carbon residue within CTP remains a central challenge in material applications. In addition, limited pore permeability and structural stability in these composites hinder the effective utilization of PA. Enhancing CTP fluidity is crucial for overcoming these challenges. In this work, a novel method was developed to modify CTP utilizing various coal tar fractions, enabling controlled modulation of CTP composition and wettability. Incorporating different fractions allowed for substantial control over interfacial bonding and pore structure. The chemical composition, functional groups, and elemental content of the CTP were analyzed via X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and proton nuclear magnetic resonance (¹H NMR). Subsequently, systematic comparisons of PA materials produced from different CTP formulations demonstrated improved wettability and enhanced mechanical properties. Moreover, DFT calculations were performed to compare the adsorption energies of small molecules from different coal tar fractions with coke, reflecting the interaction strength between the molecules and the solid surface. Using micro-computed tomography (μ-CT), the refined pore structure was examined, resulting in a PA composite with an optimized balance of high strength and toughness.

This research presents a single-walled carbon nanotube (SWCNT)-enabled real-time monitoring system to optimize post-curing conditions (temperature and duration) for epoxy resin. This method can serve as an alternative to traditional methods like Differential Scanning Calorimetry (DSC), which is effective in measuring the degree of cure in polymers during industrial curing (manufacturer-recommended cure cycle). Two different programs using SWCNTs were employed to design the cure cycles for investigating the development of mechanical properties: Program A as the comparison of effects of varied duration of high-temperature curing and Program B as high-temperature curing followed by the varied duration of low-temperature post-curing. By correlating variation in the electrical resistance of SWCNT with curing stages, we illustrate that extending post-curing at 100 °C for 24 h after an initial 3-h cure at 130 °C increases (i) tensile strength by 60% and ultimate tensile elongation by 101% and (ii) shear strength by 14% and ultimate shear elongation by 16% compared to industry standards. This approach not only improves mechanical performance but also enables precise, non-destructive cure-state detection, offering a scalable solution for high-performance composites in the aerospace and automotive sectors.

Photosupercapacitors are emerging with promising prospects for advanced applications such as wearables and IoT devices. Solar-driven systems capable of both harvesting and storing energy are increasingly viewed as practical and sustainable alternatives on a global scale. Incorporating self-charging energy units can play a transformative role in rural electrification by providing affordable and reliable power to areas where traditional electrification methods are ineffective or inaccessible. Depending on the solar cell part integrated with the supercapacitors, the photosupercapacitors can be classified as different types. In this review, we shall discuss about the most prominently reported ones based on perovskite and dye-sensitized solar cells (DSSCs).

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The aromatization degree of coal liquefaction pitch is closely related to its molecular structure evolution and the properties of derived carbon fibers. Using refined coal direct liquefaction pitch (RCLP) as raw material, pitches with different aromatization degrees were prepared by the self-pressurization/N₂ blowing two-stage thermal condensation method. Carbon fibers were then produced through melt spinning, oxidative stabilization, and carbonization. As the aromatization degree advanced, the C/H atomic ratio rose from 1.55 to 2.01, with the mesophase content nearing 100%. During RCLP thermal polymerization, large toluene-insoluble molecules were readily generated, yet the enrichment of the mesophase was comparatively sluggish. The spinnable pitch from RCLP had a relatively high aliphatic hydrogen content (33.40% ~ 13.69%) and a lower aromaticity (91.62% ~ 96.90%). Increasing aromatization made the carbon fiber cross-section’s radial transverse texture more distinct and ordered. The carbon layers stacked closely and parallelly, leading to a continuously rising tensile modulus. Due to the inhomogeneity from isotropic and anisotropic component changes, the carbon fiber tensile strength first decreased and then increased. When the spinnable pitch C/H ratio was 1.84, the mesophase pitch-based carbon fiber had an average diameter of 14.78 μm, a tensile strength of 1140 MPa, and a tensile modulus of 209 GPa.

The distinctive surface characteristics of two-dimensional(2D) materials present a significant challenge when developing heterostructures for electronic or optoelectronic devices. In this study, we present a method for fabricating top-gate graphene field-effect transistors (FETs) by incorporating a metal interlayer between the dielectric and graphene. The deposition of an ultrathin Ti layer facilitates the formation of a uniform HfO₂ layer on the graphene surface via atomic layer deposition (ALD). During the ALD process, the Ti layer oxidizes to TiO₂, which has a negligible impact on the current flow along the graphene channel. The mobility of graphene in the FET was enhanced in relation to the SiO₂-based back-gate FET by modifying the thin HfO₂ top-gate dielectric deposited on the Ti interlayer. Furthermore, shifts in the Dirac point and subthreshold swing were markedly reduced owing to the reduction in charge scattering caused by the presence of trap sites at the interface between graphene and SiO₂. This route to modulating the interface between 2D material-based heterostructures will provide an opportunity to improve the performance and stability of 2D electronics and optoelectronics.

Contamination of food with heavy metal ions and nitrites poses a serious threat to human health. Consequently, the development of fast and sensitive platforms for detecting these contaminants is urgently required. In this paper, a novel MnMgFe-LDHs/DC sensor is constructed based on a simple strategy, in which MnMgFe layered double hydroxide (LDHs) is used as a metal precursor, and a unique "island bridge" carbon network structure is generated by its pyrolysis with ZIF-8@B, N-WMCNTs. The electrical conductivity was enhanced, and a large electroactive surface area was provided for the MnMgFe-LDHs/DC. The electrochemical properties of Pb²⁺, Cd²⁺ and nitrite were investigated using this electrode as a working electrode. Under optimized conditions, the sensing platform exhibited a wide linear range with the Pb²⁺, Cd²⁺, and NO₂⁻ limits of detection of 46.16 nM, 59.25 nM, and 0.083 μM, respectively. Of particular note is that this sensing platform exhibits outstanding anti-interference capabilities. It can precisely and efficiently conduct the detection of nitrite and heavy metal ions in pickled foods.

The combination of copper and cobalt in the mixed metal oxides phase attracted considerable interest owing to their distinct characteristics and wide-ranging applications across various domains. In this study, we adopt a facile co-precipitation approach to prepare the hollow carbon spheres (HCSs) embedded with CuCo₂O₄ nanoparticles to enhance the catalytic activity. HCSs are prepared using a hydrothermal template method followed by the removal of the silica template. The resulting CuCo₂O₄ and HCSs are characterized by using X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, and Thermo-Gravimetric Analysis to ensure structural integrity and composition. Then, the CuCo₂O₄ nanoparticle is doped on the porous structure of HCSs using a surface loading method and used as a catalyst for the transfer hydrogenation of acetophenone. The scope is extended using various substrates without a hydrogen source. This nano-catalytic system shows better yields in mild reaction conditions. There was no leaching of the material into the reaction system even after five cycles, thus confirmed by ICP-MS.

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