Carbon Letters最新文献

In this study, simulated X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to differentiate the carbon nanoribbons (CNRs) and carbon nanobelts (CNBs) with different edges. CNRs, characterized by linear, extended π-conjugated systems, and CNBs, featuring closed-loop, cyclic structures, exhibit distinct bandgaps influenced by edge configuration and molecular structure. CNBs generally possess smaller bandgaps than GNRs due to enhanced π-conjugation and electron delocalization in their curved structures. Specifically, the bandgaps of zigzag-edged GNRs and CNBs are smaller than those of their armchair-edged counterparts. These differences in electronic states cause shifts in the position of the C1s XPS peaks. ANR and ANB exhibit lower binding energies (BEs) compared to ZNR and ZNB. The peak position differences, which are 1.3 eV between ZNR and ANR and 0.5 eV between ZNB and ANB, highlight how edge configuration can differentiate structures within the same ribbon or belt type. While ZNR and ZNB have nearly identical peak positions, rendering them hard to distinguish, the 0.9 eV difference between ANR and ANB allows for clear differentiation. In ZNR and ZNB, strong bands from C–H bending and C–C stretching were observed, with slight differences in band positions allowing for structural differentiation. In ANR and ANB, the Kekulé vibration band was most intense, appearing at lower wavenumbers in ANB. Additionally, ANB showed unique C–C stretching bands at 1483 and 1581 cm⁻¹, which were barely observed in ANR. This study lays the groundwork for future spectroscopic analysis of GNRs and CNBs.

With the emergence of the new energy field, the demand for high-performance lithium-ion batteries (LIBs) and green energy storage devices is growing with each passing day. Carbon nanotubes (CNTs) exhibit tremendous potential in application due to superior electrical and mechanical properties, and the excellent lithium insertion properties make it possible to be LIBs anode materials. Based on the lithium insertion mechanism of CNTs, this paper systematically and categorically reviewed the design strategies of CNTs-based composites as LIBs anode materials, and summarized in detail the enhancement effect of CNTs fillers on various anode materials. More importantly, the superiorities and limitations of various anode materials for LIBs were evaluated. Finally, the research direction and current challenges of the industrial application of CNTs in LIBs were prospected.

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Colorectal cancer (CRC) poses a significant global public health challenge, accounting for 10% of newly diagnosed cancer cases and causing 9.4% of cancer-related deaths. Conventional treatment methods like surgery, chemotherapy, and radiation have shown limited success despite the increasing incidence of CRC. Thus, there is an urgent need for innovative therapeutic approaches. Researchers are continually working on developing novel technologies, notably focused on the creation of safe and effective cancer nanomedicines, in their continuous effort to advance cancer treatment. Nanoparticles exist at the nanoscale. Nanoparticles at the nanoscale have distinctive properties that leverage the metabolic disparities between cancerous and normal cells. This property allows them to selectively induce substantial cytotoxicity in cancer cells while minimizing damage to healthy tissue. Carbon nanomaterials (CNMs), including graphene oxide (GO), carbon nanotubes (CNTs), and nanodiamonds (NDs), have undergone extensive investigation due to their biocompatibility, surface-to-volume ratio, thermal conductivity, rigid structural properties, and ability for post-chemical modifications. Notably, GO has emerged as a promising two-dimensional (2D) material for cancer treatment. Several groundbreaking nanoparticle-based therapies, predominantly utilizing GO, are currently undergoing clinical trials, with some already gaining regulatory clearance.

The feeder pipes of the primary cooling system in a pressurized heavy water reactor (PHWR) are composed of carbon steel SA 106 GR.B. On the surface of this structural material, corrosion oxide layers including radionuclides are formed due to the presence of active species from water decomposition products caused by radiation, as well as the high temperature and high-pressure environment. These oxide layers decrease the heat transfer efficiency of the primary cooling system and pose a risk of radiation exposure to workers and the environment during maintenance and decommissioning, making effective decontamination essential. In this study, we simulated the formation of the corrosion oxide layer on the surface of carbon steel SA 106 GR.B, characterized the formed corrosion oxide layer, and investigated the dissolution characteristics of the corrosion oxide layer using oxalic acid (OA), a commercial chemical decontamination agent. The corrosion oxide layer formed has a thickness of approximately 4 µm and consists of hematite (Fe₂O₃) and magnetite (Fe₃O₄). The carbon steel coupons with formed oxide layers were dissolved in 10 mM and 20 mM OA solutions, resulting in iron ion concentrations of 220 ppm and 276 ppm in the OA respectively. In 10 mM and 20 mM OA, the corrosion depths of the coupons were 8.93 µm and 10.22 µm, with corrosion rates of 0.39 mg/cm²·h and 0.45 mg/cm²·h, respectively. Thus, this demonstrates that higher OA concentrations lead to increased dissolution and corrosion of steel.

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This study examines the effects of the TiO₂ content and TiO₂ position in the core or shell within tubular carbon nanofibers on the photocatalytic activity under visible light. Core–shell tubular carbon nanofiber composites whose cores are filled with TiO₂ nanoparticles (PMTi(10)P) are fabricated through coaxial electrospinning and subsequent heat treatment. The PMTi(10)P composites with well-preserved TiO₂ nanoparticles in the core part induce more oxygen vacancies, Ti³⁺ species, chemisorbed oxygen species, and anatase phases, significantly improving the photocatalytic performance. They act as photoelectron traps, allowing more photoelectrons and holes to participate in the photocatalytic reaction and extending the absorbance of TiO₂ to the visible light region. The resulting PMTi(10)P photocatalyst exhibits excellent performance of 100% removal of methylene blue within 30 min and maintains nearly 100% removal of 15 ppm methylene blue over 10 regeneration cycles, indicating consistent and stable photocatalytic performance.

A substantial quantity of discarded tires has inflicted harm on the environment. Microwave pyrolysis of discarded tires emerges as an efficient and environmentally friendly method for their recycling. This research innovatively utilizes the characteristics of microwave rapid and selective heating to pyrolyze waste tires into porous graphene under the catalysis of KOH etching. Moreover, this study comprehensively investigates the dielectric characteristics and heating behavior of waste tires and different proportions of waste tire–KOH mixtures. It validates the preparation of graphene through KOH-catalyzed microwave pyrolysis of waste tires, tracking morphological and structural changes under varying temperature conditions. The results indicate that optimal dielectric performance of the material is achieved at an apparent density of 0.68 g/cm³ at room temperature. As the temperature increases, the dielectric constant gradually rises, particularly reaching a notable increase around 700 °C, and then stabilizes around 750 °C. Additionally, the study investigates the penetration depth and reflection loss of mixtures with different proportions, revealing the waste tire–KOH mass ratio of 1:2 demonstrates favorable dielectric properties. This research highlights the impressive microwave responsiveness of the waste tire–KOH mixture, Upon the addition of KOH, the mixed material exhibits an augmented dielectric constant and relative dielectric constant, supporting the viability of KOH-catalyzed microwave pyrolysis for producing porous graphene from waste tires. This method is expected to provide a new method for the valuable reuse of waste tires and a technology for large-scale, efficient and environmentally friendly production of graphene.