Carbon最新文献

In this study, nitrogen-doped graphene (NG) coated 6061 Al alloy (NG/Al) was prepared using a novel roll-coating technique. Through Raman and X-ray photoelectron spectroscopy analyses (XPS), the NG films with varying graphitic-N content obtained by plasma treatment was investigated. The electrochemical impedance spectroscopy, polarization curve, and immersion test were used to study the corrosion behaviors of the films. The results show that NG/Al exhibits enhanced corrosion resistance properties due to the enhanced adhesion between Al substrate and NG. In particular, the prepared NG/Al with the highest graphitic-N content shows superior resistance against both 0.5 M H₂SO₄ and 3.5 wt% NaCl.

Global warming, contributing to the worsening climate crisis, has led to more frequent heavy snowfall and rainfall. This causes corrosion, mold, and structural damage to roofs, which shortens the roofs' lifespan and potentially creates safety hazards. Addressing these challenges, we propose an approach to develop a multifunctional roof crucial for proactive adaptation to extreme weather. In this article, we present hydrophobic laser-induced graphene (LIG) onto wood in a single-step process using femtosecond-laser-direct-writing (FsLDW) technology in ambient air without additional chemical treatment. This hydrophobic LIG, showcasing a high electrical conductivity of 10.0 Ω·sq⁻¹ and a high contact angle of 148.8°, seamlessly integrates onto roofs, creating cost-effective, fast, eco-friendly, and smart roofing solutions. The hydrophobic surface of these LIG electrodes incorporates a heating function of LIG showcasing their versatility in providing waterproofing, drying wood, and facilitating de-icing functions. This eco-friendly invention, reliant solely on laser patterning on wood, not only extends roof lifespan but also relieves concerns about electronic waste and recycling, promising the integration of green, smart, and sustainable roofing solutions.

Surface-active agents, such as surfactant molecules, are essential for stabilizing liquid-exfoliated graphene and other 2D nanosheets in water through electrostatic or steric repulsion. It is important to note that surfactants are no longer necessary for solutions converted into thin films for electronic devices, sensors, and composite applications. High-temperature (∼400–500 °C) thermal annealing is one of the performed methods to remove surfactant molecules. However, the surfactant residues present on the graphene nanosheets by post-annealing may adversely impact the electronic properties of the graphene film, potentially resulting in additional doping and defects. To address this challenge, we report a low-temperature decomposable (∼320 °C), eco-friendly and industrially viable surfactant, i.e., coco-glucoside, for the efficient liquid-phase exfoliation and stabilization of graphene nanosheets in water. Compared with the well-studied surfactants in liquid exfoliation such as sodium dodecyl benzene sulphonate (SDBS) and sodium cholate (SC), ∼90 % of this surfactant molecules completely decomposed at ∼320 °C in an air atmosphere for coco-glucoside. Electrical conductivity studies suggested that annealing at 320 °C enhanced the conductivity by 15 times for the coco glucoside-stabilized graphene film; however, marginal change in the conductivity was observed for the SDBS and SC-stabilized graphene film. To demonstrate the viability of the concept, a wallpaper-based rapid fire alarm application utilizing coco glucoside-stabilized graphene/cellulose paper was demonstrated.

The careful selection of carbon precursors for chemical activation is critical in obtaining cost-effective and efficient porous activated biocarbons with multifunctional properties. Herein, we report on utilising almond skin to synthesize porous activated biocarbons via solid-state KOH activation. Through precise manipulation of the impregnation ratio of KOH to the non-porous carbon, a range of materials with intriguing properties including high surface area, large pore volume, tunable micro and mesopores, and surface functionalization with oxygen were synthesized. The optimized material ASPC5-4 displayed an extremely high surface area (3535 m² g⁻¹), a large pore volume (1.9 cm³ g⁻¹), a high proportion of mesopores (96.5 %) and a notable surface oxygen content (6.93 wt %). These excellent features allowed ASPC5-4 to adsorb a record amount of CO₂ at 0 °C/30 bar (39.81 mmol g⁻¹). Another material ASPC5-2 exhibited a high content of micropores and adsorbed 5.92 mmol g⁻¹ of CO₂ at 0 °C/1 bar. ASPC5-4 also exhibited great potential as a supercapacitor electrode, displaying a high specific capacitance in both a three-electrode (354 F g⁻¹/0.5 A g⁻¹) and two-electrode (203 F g⁻¹/0.5 A g⁻¹) systems. It also demonstrated high power and energy densities of 638 W kg⁻¹ and 47 W h kg⁻¹, respectively.

In the dynamic field of microelectronics, there is a notable trend towards leveraging carbon materials, favored for their ease of synthesis, biocompatibility, and abundance. This trend is particularly evident in the development of memristor devices, which benefit from the unique electronic properties of carbon, leading to enhanced device performance. The appeal of carbon materials lies in their ability to offer distinctive resistive switching (RS) mechanisms, sparking significant interest among researchers. This article aims to provide an insightful overview of the advancements in carbon-based memristive devices, focusing on the resistive switching mechanisms enabled by carbon materials. It delves into the various classes of carbon-based memristor devices, ranging from zero-dimensional (0D) to three-dimensional (3D) structures, each with its unique advantages and applications. Additionally, the discussion extends to innovative next-generation memristive devices, including those designed for health monitoring and skin-adhesive, self-powered applications. Moreover, the article touches upon the synthesis techniques and functionalization strategies that are crucial for optimizing the performance of carbon-based memristors. It also outlines the future opportunities in this rapidly advancing field, highlighting the potential for further research and development towards energy-efficient, compact, and bio-integrated memristive systems.

Metal-organic frameworks (MOFs)-derived electromagnetic functional materials are a hot research trend in the field of microwave absorption (MA). However, there is a lack of high-yield strategies to drive high-performance MOFs-derived MA absorbers out of the laboratory. Herein, we prepared MIL-88B-like using a simple room-temperature liquid-phase method with more than 75 times the yield of the solvothermal method. The obtained MOFs were pyrolyzed to form C/FeO/FeN_0.0324/Fe quaternary composite materials. Under suitable graphitizing conditions, the moderate conductivity of derivative material of M1 precursor carbonized at 700 °C (M1-700) not only meets the requirement of impedance matching but also provides high conduction loss. Meanwhile, the multiple polarization loss mechanisms from defect-induced polarization, dipole polarization, heterogeneous interfaces, and magnetic loss mechanism synergize with each other, resulting in an effective absorption bandwidth (EAB) of 6.71 GHz and a reflection loss (RL) value of −62.57 dB at 22.5 wt% filler, which is a 6-fold increase in the RL compared with that of the conventional MIL-88B-derived wave absorber. In conclusion, this work provides a feasible solution for practical absorbers and an excellent reference value for high MA performance materials for applications.

Exploring the chemistry of materials at high pressure leads to discoveries of previously unknown compounds and phenomena. Here chemical reactions between elemental dysprosium and carbon were studied in laser-heated diamond anvil cells at pressures up to 95 GPa and temperatures of ∼2800 K. In situ single-crystal synchrotron X-ray diffraction (SCXRD) analysis of the reaction products revealed the formation of novel dysprosium carbides, γ-DyC₂, Dy₅C₉, and γ-Dy₄C₅, along with previously reported Dy₃C₂ and Dy₄C₃. The crystal structures of γ-DyC₂ and Dy₅C₉ feature infinite flat carbon polyacene-like ribbons and cis-polyacetylene-type chains, respectively. In the structure of γ-Dy₄C₅, carbon atoms form dimers and non-linear trimers. Dy₃C₂ contains ethanide-type carbon dumbbells, and Dy₄C₃ is methanide featuring single carbon atoms. Density functional theory calculations reproduce well the crystal structures of high-pressure dysprosium carbides and reveal conjugated π-electron systems in novel infinite carbon polyanions. This work demonstrates that complex carbon homoatomic species previously unknown in organic chemistry can be synthesized at high pressures by direct reactions of carbon with metals.

Catalyst control is critical to carbon nanotube (CNT) growth and scaling their production. In supported catalyst CNT growth, the reduction of an oxidized metal catalyst enables growth, but its reduction also initiates catalyst deactivation via Ostwald ripening. Here, we conducted autonomous experiments guided by a hypothesis-driven machine learning planner based on a novel jump regression algorithm. This planning algorithm iteratively models the experimental response surface to identify discontinuities, such as those created by a material phase change, and targets further experiments to improve the fit and reduce uncertainty in its model. This approach led us to identify conditions that resulted in the greatest CNT yields as a function of the driving forces of catalyst reduction in a fraction of the time and cost of conventional experimental approaches. By varying temperature and the reducing potential of the growth atmosphere, we identified discontinuous jumps in CNT growth for two thicknesses of an iron catalyst, resulting in largest observed yields in narrow and distinct regions of thermodynamic space where we believe the reduced catalyst is in equilibrium with its oxide. At these jumps, we also observed the longest growth lifetimes and a greater degree of diameter control. We believe that conducting CNT growth at these conditions optimizes catalyst activity by inhibiting Ostwald ripening-induced deactivation, thereby keeping catalyst nanoparticles smaller and more numerous. This work establishes a thermodynamic framework for a generalized understanding of metal catalysts in CNT growth, and demonstrates the capability of iterative, hypothesis-driven autonomous experimentation to greatly accelerate materials science.

Poor wetting and bonding serve as significant challenges in the joining of carbon materials at low temperatures. In this work, the ultrasonically assisted hot dipping of pyrolytic graphite was investigated in a SnAgCu–2Al liquid metal at a low temperature of 250 °C in air. During the ultrasonic-assisted hot-dipping process, the filler metal filled into the surface grooves of pyrolytic graphite. A closely contacting interface formed between the pyrolytic graphite and the filler metal. Interlayer penetration induced by the cavitation effect, and the amount and depth of penetration increased with ultrasonication time. A transition layer of Al₂O₃ was formed at the interface between pyrolytic graphite and the filler metal. Large amounts of O atoms were induced at the interface during the ultrasonically assisted hot-dipping process, and the reaction of Al and O preferentially occurred between the liquid metal and solid C. This was consistent with the thermodynamic calculation results. The joining of metallizing-pyrolytic graphite was achieved by soldering at same temperature of 250 °C in air, where the highest joint strength could reach 17.52 MPa, achieving a joining module with a high thermal conductivity of 392 W/(m·K) and reaching 90 % of the base material.