Carbon最新文献

Carbon aerogel (CA) is recognized as a promising microwave absorption (MA) material, but it remains greatly challenging to integrate the multiple functions of MA, mechanical strength, and heat insulation. In this work, a novel zirconia fiber reinforced CA (ZF/CA) composite is successfully fabricated via electrospinning technology coupled with a sol-gel impregnation process for the first time. The density (0.132–0.206 g/cm³) of the obtained ZF/CA composites can be regulated by simply varying the initial sol concentration, thus effectively tuning their performance. Notably, the ZF/CA composites display excellent MA properties, with a strong absorption of −80.30 dB at the thickness of merely 1.71 mm and the optimal effective absorption bandwidth reaches 5.16 GHz, which is a significant improvement compared to CA (−11.70 dB, 0.58 GHz). Simultaneously, the brittleness and cracking problems of CA are effectively addressed by the soft reinforcement strategy of electrospun zirconia fibers, and superior mechanical strength is obtained. Furthermore, the nanopore structure and hierarchical design endow the ZF/CA composites with low thermal conductivity (0.029–0.038 W m⁻¹ K⁻¹) and favorable heat insulation performance. Outstanding MA capacity and excellent heat insulation properties along with lightweight construction and high strength make ZF/CA composites a great candidate for efficient MA and heat insulation.

Interfacial engineering and morphology design are two popular strategies to strengthen the performance of carbon-based composites as electromagnetic wave absorbing materials (EWAMs). Herein, we integrate their advantages simultaneously in ternary MoC/Co/C composites (SMCCs). On one hand, highly dispersed MoC and Co nanoparticles create abundant heterogeneous interfaces, and on the other hand, the spatial star-like carbon skeletons derived from ZnCo-MOF also bring significant structure contribution to EM energy consumption. EM measurement reveals that the pyrolysis temperature greatly impacts EM properties of SMCCs. After blending with paraffin (organic binder), the mixture that involves SMCC-800 (pyrolyzed at 800 °C) may have both good impedance matching degree and powerful EM attenuation ability. As a result, SMCC-800/paraffin displays excellent EM absorption performance, including strong reflection loss intensity down to −67.3 dB at 16.2 GHz (thickness: 1.8 mm) and broad response bandwidth of 6.0 GHz (12.0–18.0 GHz, thickness: 2.0 mm) less than −10.0 dB, which outdo the performance of many composites with similar chemical composition ever reported. The EM absorption mechanism of SMCC-800/paraffin is comprehensively illustrated through the investigation on EM properties of the mixtures with various control samples.

Nano-carbon materials (graphene, carbon nanotube) are considered as ideal reinforcements for metal matrix composites (MMCs) due to their excellent mechanical and physical properties. However, discontinuous nanocarbon-reinforced MMCs with homogeneous configuration cannot maximize the synergistic coupling effect between reinforcement and matrix mainly due to their anisotropic nanocarbon geometry and weak carbon-metal interfacial bonding. In recent years, nanocarbon-reinforced MMCs with non-uniform architectures including laminate, 3D network, alignment and hierarchical architectures have been reported and the overall performance of the composites can be effectively improved. Therefore, in this review, the methods for fabrication of nano-carbon reinforced MMCs with these architectures are summarized. The properties including mechanical and conductive properties, and structure-property relationship of these composites with different architectures are analyzed. Finally, possible research directions and challenges for architecture design in nanocarbon-reinforced MMCs are outlined.

Fluorinated graphene (FG) is considered an ideal filler for polymer nanocomposites to enhance anti-corrosion performance due to its hydrophobicity and electrical insulation properties. A key objective in advanced anti-corrosion design is to create a structure where FG sheets are stacked and aligned, forming an ultra-long, circuitous path to impede the diffusion of active corrosion species. Additionally, integrating aligned FG sheets with polymers prevents the formation of electrical percolation paths, making the coating suitable for electronic passivation. However, achieving a high degree of alignment of FG within the polymer matrix has been a challenge. In this study, we employ a straightforward electrophoretic deposition method to align FG sheets in a polyurethane (PU) matrix for anti-corrosion coatings on copper. The optimized coating exhibits outstanding corrosion resistance for copper, with a stable corrosion rate of 4.0 × 10⁻³ μm/year in a 3.5 wt% NaCl solution. Moreover, the FG composite coating significantly enhances thermal conductivity, increasing it by 97 % compared to pristine PU, while also providing high electrical resistance. This results in a high breakdown electric field of 28 kV/cm and an extremely low current density of 1.32 × 10⁻⁸ A/cm², which is advantageous for electronic packaging. This multifunctional coating meets industrial standards for large-scale production, uniformity, and controllable thickness, offering a promising approach to improving anti-corrosion protective coatings.

Mesoporous carbon-doped hexagonal boron nitrides (C-doped BN) with high surface area were prepared by annealing organic resin polymer/silica in NaBH₄ and NaNH₂ inorganic salts, which were found to be efficient metal-free bifunctional electrocatalyst for both 2e⁻ ORR and 2e⁻ WOR. It could efficiently catalyze 2e⁻ ORR to H₂O₂ in 2 M KHCO₃ (1650 mmol g⁻¹ h⁻¹) with Faraday efficiency of 93–98 % in half reaction, while it was very active for 2e⁻ WOR to generate H₂O₂ in 2 M KHCO₃ with 551 mmol g⁻¹ h⁻¹ H₂O₂ production rate in half reaction. When pairing them in one H-type cell, H₂O₂ solution could be totally produced over C-doped BN in both anode and cathode cells. The better electron conductivity from sharper band gap caused by carbon doping and higher surface area of 304 m² g⁻¹ contributed to its efficient electrocatalytic activity. The C-doped BN served an effective bifunctional electrocatalyst for 2e⁻ ORR and 2e⁻ WOR.

Self-lubricating coating has sparked significant research interest due to its remarkable tribology performance. However, traditional microcapsules-based self-lubricating coating still faces challenges in long-term serviceability and poor anti-corrosion performance. In this paper, a novel self-lubricating epoxy resin coating was proposed based on hierarchical design and energy wear theory. Microcapsules (MC) containing Polyalphaolefin (PAO40) were prepared via the solvent evaporation approach. Ti₃C₂T_x MXene (T) with high thermal conductivity was then incorporated into the MC-enhanced epoxy resin coating (EP) to construct the novel self-lubricating EP coating (T-MC-EP). Compared to the EP coating, the thermal conductivity of the T-MC-EP coating increased by 79.4%. Finite element analysis indicated that T constructed thermally conductive network in the coating, serving as the main heat carrier. Furthermore, the wear rate decreased by 91.2%, primarily attributed to the formation of lubricating oil film during friction and the reduction of epoxy resin molecular oxidation fracture caused by friction heat. After 31 days of salt spray testing, the T-MC-EP coating also exhibited superior anti-corrosion performance. This work provides an innovative insight into designing multifunctional coating, including excellent mechanical, thermal, tribological, and anti-corrosive performance.

Glutathione (GSH) holds a vital role in biological systems, serving diverse cellular functions. Selective determination of GSH over cysteine (Cys) and homocysteine (Hcy) stays challenging due to the shared functional groups among these biothiols. In this study, a versatile Eu-doped carbon dots (Eu-CDs) nanoprobe has been developed for the exceptionally sensitive and selective detection of GSH in biological fluids. The synthesized Eu-CDs exhibited high solubility in water, stability to salt and pH variations, and consistent fluorescence emission, boasting a quantum yield of 40.67 %. Following the optimization of detection parameters, a robust linear relationship for GSH was established in the concentration range of 0.0–50 μM, with a detection limit of 0.03 μM. The viability of the technique in actual samples was evaluated by successfully measuring the GSH in urine and human serum samples with a range recovery from 90.6 % to 98.5 %. Furthermore, Eu-CDs proved to be exceptionally suitable for imaging Hela cells owing to their low cytotoxicity and remarkable biocompatibility. As a result, the developed fluorescent biosensor demonstrated significant potential for widespread application in clinical diagnostic analyses.

Embarking into unexplored realms beyond the C₁ equatorial_-face and C₁ trans-4′ regioisomers, this study delves into the synthesis of cis-2ʹ C₅₉N bisadducts. The synthesis involves a two-step process. Firstly, a Mannich-type reaction between bisazafullerene (C₅₉N)₂ and a tether yields a monoadduct. Further Bingel-Hirsch cyclopropanation results in the formation of the desired cis-2ʹ C₅₉N bisadducts. Comprehensive spectroscopic techniques, including polarimetry and X-ray crystallography, confirm the absolute configuration (^f,sclockwise or ^f,santiclockwise) of the enantiomerically pure cis-2ʹ C₅₉N bisadducts. Circular dichroism measurements revealed the extremely high chiroptical activity of these inherently chiral bisadducts. Evaluation of their optoelectronic properties through Vis-NIR absorption, PL emission, and cyclic voltammetry techniques reveals distinctive bandgap and NIR emission, ranging from 1.31 to 1.81 eV and 700–1108 nm, respectively, showcasing promising potential for applications in energy conversion.