Search Results (498)

The electrochemical conversion of CO₂ into high-purity Graphene NanoCarbon (GNC) materials provides a compelling path to address climate change while producing economically valuable nanomaterials. This work presents the progress and prospects of new large-scale syntheses of GNC allotropes via the C2CNT (CO₂ to Carbon Nano Technology) process. The C2CNT molten carbonate electrolysis technique enables the formation of Carbon NanoTubes (CNTs), Magnetic CNTs (MCNTs), Carbon Nano-Onions (CNOs), Carbon Nano-Scaffolds (CNSs), and Helical CNTs (HCNTs) directly from atmospheric or industrial CO₂. We discuss the morphology control enabled through variations in electrolyte composition, temperature, current density, and nucleation additives. We present results from scaled operations reaching up to 1000 tons/year CO₂ conversion and propose design approaches to reach megaton scales to support climate mitigation and GNC mass production. The products demonstrate high crystallinity, as evidenced by Raman, XRD, SEM, and TGA analyses, and offer promising applications in electronics, construction, catalysis, and medical sectors. Full article

In this paper, nanoscale graphene film electrodes were prepared using laser-induced technology, and an in situ electrochemical cell was constructed. The normalized peak areas at 2.82 ppm for the samples without the in situ electrochemical cell and with an in situ electrochemical cell are 4.02 and 4.41, respectively. Tests showed that this in situ electrochemical cell has minimal interference from the nuclear magnetic resonance (NMR) magnetic field, allowing for high-resolution in situ spectra. Using this in situ electrochemical cell and employing in situ electrochemistry combined with NMR techniques, we investigated the oxidation reaction of 0.01 M procarbazine (PCZ) in real-time. We elucidated the following oxidation mechanism for procarbazine: the oxidation of PCZ first generates azo-procarbazine, which then undergoes a double bond shift to hydrazo-procarbazine. hydrazo-procarbazine undergoes hydrolysis to yield benzaldehyde-procarbazine, and then finally oxidizes to produce N-isopropylterephthalic acid. This confirms that the combination of in situ electrochemistry and nuclear magnetic resonance technology provides chemists with an effective tool for in situ studying the reaction mechanisms of drug molecules. Full article

Due to its persistence and potential negative effects on ecosystems and human health, microplastic pollution in aquatic environments has become a major worldwide concern. Photocatalytic degradation is a sustainable manner to degrade microplastics to non-toxic by-products. In this review, comprehensive discussion focuses on the synergistic effects of various photocatalytic materials including TiO₂, ZnO, WO₃, graphene oxide, and metal–organic frameworks for producing heterojunctions and involving multidimensional nanostructures. Such mechanisms can include the generation of reactive oxygen species and polymer chain scission, which can lead to microplastic breakdown and mineralization. The advancements of material modifications in the (nano)structure of photocatalysts, doping, and heterojunction formation methods to promote UV and visible light-driven photocatalytic activity is discussed in this paper. Reactor designs, operational parameters, and scalability for practical applications are also reviewed. Photocatalytic systems have shown a lot of development but are hampered by shortcomings which include a lack of complete mineralization and production of intermediary secondary products; variability in performance due to the fluctuation in the intensity of solar light, limited UV light, and environmental conditions such as weather and the diurnal cycle. Future research involving multifunctional, environmentally benign photocatalytic techniques—e.g., doped composites or composite-based catalysts that involve adsorption, photocatalysis, and magnetic retrieval—are proposed to focus on the mechanism of utilizing light effectively and the environmental safety, which are necessary for successful operational and industrial-scale remediation. Full article

This study presents a detailed and comprehensive investigation into the macro-scale performance, strength gain mechanisms, environment and economic performance of graphene oxide (GO)-enhanced low-emission concrete. A comprehensive experimental program evaluated fresh and hardened properties, including slump retention, bleeding, air content, compressive, flexural, and tensile strength, drying shrinkage, and elastic modulus. Scanning Electron Microscopy (SEM), energy-dispersive spectroscopy (EDS), Thermogravimetric analysis (TGA) and proton nuclear magnetic resonance (¹H-NMR) was employed to examine microstructural evolution and early age water retention, confirming GO’s role in accelerating cement hydration and promoting C-S-H formation. Optimal performance was achieved at 0.05% GO (by binder weight), resulting in a 25% increase in 28-day compressive strength without compromising workability. This outcome is attributed to a tailored, non-invasive mixing strategy, wherein GO was pre-dispersed during synthesis and subsequently blended without the use of invasive mixing methods such as high shear mixing or ultrasonication. Fourier-transform infrared (FTIR) spectroscopy further validated the chemical compatibility of GO and PCE and confirmed the compatibility and efficiency of the admixture. Sustainability metrics, including embodied carbon and strength-normalized cost indices (USD/MPa), indicated that, although GO increased material cost, the overall cost-performance ratio remained competitive at breakeven GO prices. Enhanced efficiency also led to lower net embodied CO₂ emissions. By integrating mechanical, microstructural, and environmental analyses, this study demonstrates GO’s multifunctional benefits and provides a robust basis for its industrial implementation in sustainable infrastructure. Full article

Two-dimensional (2D) crystals which present unconventional stoichiometries on graphene surfaces in ambient conditions, such as Na₂Cl, Na₃Cl, and CaCl, have attracted significant attention in recent years due to their electronic structures and abnormal cation–anion ratios, which differ from those of conventional three-dimensional crystals. This unconventional crystallization is attributed to the cation–π interaction between ions and the π-conjugated system of the graphene surface. Consequently, their physical and chemical properties—including their electrical, optical, magnetic, and mechanical characteristics—often differ markedly from those of conventional crystals. This review summarizes the recent progress made in the fabrication and analysis of the structures, distinctive features, and applications of these 2D unconventional stoichiometry crystals on graphene surfaces in ambient conditions. Their special properties, including their piezoelectricity, metallicity, heterojunction, and room-temperature ferromagnetism, are given particularly close attention. Finally, some significant prospects and further developments in this exciting interdisciplinary field are proposed. Full article

T-2 toxin, a type A trichothecene mycotoxin produced by Fusarium species, is widely present in cereals and their processed products, posing a significant contaminant in food safety. To address the food safety challenges caused by this toxin, we established a dual signal enhancement by magnetic separation and split aptamer for ultrasensitive T-2 toxin detection. In this method, the introduction of magnetic graphene oxide (MGO) enhanced signal and increased sensitivity by reducing background interference. The shortened split aptamer reduces non-specific binding to MGO via decreased steric hindrance, thereby facilitating rapid target-induced dissociation and signal generation. A FAM fluorophore-labeled split aptamer probe FAM-SpA1-1 was quenched by MGO. While the fluorescence intensity remained nearly unchanged when the unlabeled split aptamer probe SpA1-2 was introduced alone, a significant fluorescence recovery was observed upon simultaneous addition of SpA1-2 and T-2 toxin. This recovery resulted from the cooperative binding of SpA1-1 and SpA1-2 to T-2 toxin, which distanced the FAM-SpA1-1 probe from MGO. Therefore, the proposed biosensor demonstrated excellent stability, reproducibility, and specificity, with a linear response range of 10–500 pM and a limit of detection (LOD) of 0.83 pM. Satisfactory recovery rates were achieved in spiked wheat (86.0–114.2%) and beer (112.0–129.6%) samples, highlighting the biosensor’s potential for practical applications in real-sample detection. This study establishes the T-2 toxin split aptamer and demonstrates a novel dual-signal enhancement paradigm that pushes the sensitivity frontier of aptamer-based mycotoxin sensors. Full article

In this paper, magnetically responsive graphene/boron nitride/iron oxide fillers were prepared by growing iron oxide on the surface of graphene/boron nitride fillers via liquid-phase reaction. By adding the composite filler into the epoxy resin and utilising magnetic field-assisted curing, the composites were prepared to effectively improve the thermal conductivity of the composites while maintaining the insulating properties. The thermal conductivity of the composite filler is 2.1 Wm⁻¹K⁻¹, and the volume resistance is 4.63 × 10¹² Ω·cm when the mass ratio of the composite filler is 25%, and the thermal stability and ablation resistance of the composites are improved compared with that of the pure epoxy resin. Full article

Nanotechnology has emerged as a highly focused field of research due to the unique properties of nanometric materials, particularly their large specific surface areas and excellent adsorption capabilities. This study investigated the synthesis of materials based on graphene oxide (GO) functionalized with different metal oxides (MnO₂, Fe₃O₄, CuO, NiO), with potential applications in water decontamination. The morphological, structural, and compositional properties of these nanocomposites were extensively characterized using different experimental techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) for magnetic property evaluation. Preliminary adsorption tests were performed for the removal of pesticides and drugs from aqueous solutions. The synthesized materials demonstrated a higher affinity for selected pesticides compared to drugs. The best removal efficiencies were 98.59% for cymoxanil, 97.93% for triadimefon, 63.33% for sulfamethoxazole, and 99.59% for diclofenac. The results indicate that the functionalization of GO with metal oxides modifies the material’s structure, increasing its potential for environmental applications such as water purification. Full article

In this study, we report the synthesis of few-layer graphene via ultrasonic treatment of a graphite-benzene solution at room temperature. Raman spectroscopy revealed a significant reduction in the intensity ratio of the G and 2D peaks for samples subjected to 20 min of treatment, indicating a decrease in defect density and oxidation. Prolonged treatment times led to fragmentation of the graphene sheets, which facilitated restacking, as evidenced by Raman spectroscopy and microscopy. FTIR analysis confirmed the complete removal of the solvent from the extracted and dried graphene. Additionally, electron paramagnetic resonance (EPR) measurements indicated the presence of carbon-based magnetism in the synthesized samples, suggesting potential applications in spintronic devices. Our findings highlight the effectiveness of ultrasonic treatment for producing high-quality few-layer graphene with desirable structural and magnetic properties. Full article

By combining density functional theory with the non-equilibrium Green’s function method, we conducted a first-principles investigation of spin-dependent transport properties in a molecular device featuring a dynamic covalent chemical bridge connected to zigzag graphene nanoribbon electrodes. The effects of spin-filtering and spin-rectifying on the I–V characteristics are revealed and explained for the proposed molecular device. Interestingly, our results demonstrate that all three devices exhibit significant single-spin-filtering behavior in parallel (P) magnetization and dual-spin-filtering effects in antiparallel (AP) configurations, achieving nearly 100% spin-filtering efficiency. At the same time, from the I–V curves, we find that there is a weak negative differential resistance effect. Moreover, a high rectifying ratio is found for spin-up electron transport in AP magnetization, which is explained by the transmission spectrum and local density of state. The fundamental mechanisms governing these phenomena have been elucidated through a systematic analysis of spin-resolved transmission spectra and spin-polarized electron transport pathways. These results extend the design principles of spin-controlled molecular electronics beyond graphene-based systems, offering a universal strategy for manipulating spin-polarized currents through dynamic covalent interfaces. The nearly ideal spin-filtering efficiency and tunable rectification suggest potential applications in energy-efficient spintronic logic gates and non-volatile memory devices, while the methodology provides a framework for optimizing spin-dependent transport in hybrid organic–inorganic nanoarchitectures. Our findings suggest that such systems are promising candidates for future spintronic applications. Full article

Gastrointestinal submucosal tumors (SMTs) are difficult to diagnose accurately due to their deep location and the limitations of traditional biopsy tools. To address these issues, we propose a multifunctional capsule-shaped puncture biopsy robot (PBR) with capabilities for tissue sampling, thermal hemostasis, and multi-stage drug delivery. The PBR measures 27 mm in length and 13 mm in diameter, integrating a micro-scale electro-permanent magnetic system with a 60-turn dual-layer coil (wire diameter: 0.6 mm) to drive an 8 mm-depth puncture needle. A graphene–carbon nanotube composite heating film enables rapid and safe temperature elevation, achieving effective hemostasis and triggering sequential drug release using paraffin-based phase-change materials. Heating remains within the clinical safety range. Experiments demonstrated successful tissue penetration, precise magnetic control, and reliable staged pigment release simulating drug delivery. Tests on an ex vivo porcine stomach confirmed adaptability to irregular gastric surfaces. This compact PBR provides an integrated and minimally invasive approach to both the diagnosis and treatment of gastrointestinal lesions. Full article

The impact of rhenium doping on the transport properties and electron localization in monolayer graphene was experimentally investigated. In this study, we report the emergence of unsaturated negative magnetoresistance in Re-doped graphene devices, which is observed exclusively at low temperatures. Moreover, angle-dependent measurements reveal a pronounced anisotropy in the negative magnetoresistance. This phenomenon is attributed to the disorder and localized magnetic moments introduced by Re doping, which lead to charge carrier localization and are accompanied by substantial magnetocrystalline anisotropy energy. Full article

We propose a DNA nucleobase sequencing device composed of zigzag graphene nanoribbon electrodes connected with a porphyrin molecule via carbon chains (GEPM). The connecting geometry between the nanoribbons with an even width number and the carbon chains is laterally symmetric to filter out electrons of specific modes. Various properties of the GEPM and of the GEPM + nucleobase systems, such as interaction energies, charge density differences, spin-differential electronic densities, and electric currents, are investigated using the density functional theory (DFT) combined with the non-equilibrium Green’s function (NEGF) method. The results show that the GEPM device holds promise for DNA sequencing with the measurement of the electric signals through it. The four nucleobases—adenine (A), cytosine (C), guanine (G), and thymine (T)—can be efficiently distinguished based on the conductance and current sensitivity when they are located on the porphyrin molecule of the GEPM device. The symmetry of the connecting geometry between the carbon chains and the nanoribbons selects Bloch states with specific symmetry to pass through the device and results in broad transmission valleys or gaps. In addition, the edge magnetism of graphene nanoribbons can further manipulate the transmission and then the sequencing effects. The device exhibits extremely high conductance sensitivity in the parallel magnetic configuration. This study explores the possible advantage of this technology compared with conventional nanopore sequencing devices and potentially expands the variety of available sequencing structures. Full article

Glucose detection is critical in addressing health and medical issues related to irregular blood levels. Colorimetry, a simple, cost-effective, and visually straightforward method, is often employed. Traditional enzymatic detection methods face drawbacks such as high costs, limited stability, and operational challenges. To overcome these, enzyme mimics or artificial nano-enzymes based on inorganic nanomaterials have garnered attention, but their cost and susceptibility to inactivation limit applications. This study presents a ZnFe₂O₄/GQDs nanocomposite as an innovative enzyme mimic, addressing key requirements like low cost, high stability, biocompatibility, and wide operational range. Synthesized using a simple and inexpensive method, the composite benefits from the synergistic interaction between ZnFe₂O₄ nanoparticles and graphene quantum dots (GQDs), resulting in excellent magnetic properties, high surface area, and functional versatility. The material demonstrated remarkable sensitivity with a detection limit of 7.0 μM across a range of 5–500 μM and achieved efficient peroxidase-like activity with Km values of 0.072 and 0.068 mM and Vmax of 4.58 × 10⁻⁸ and 8.29 × 10⁻⁸ M/s for TMB and H₂O₂, respectively. The nanocomposite also exhibited robust recyclability, retaining performance over six reuse cycles. Full article