Explore the vast range of titles available.

Graphene has emerged as a highly attractive nanomaterial, characterized by its distinctive thermodynamic, electrical, and mechanical features. These attributes render it ideal for a wide array of purposes across materials research, storing energy, computing, filtering water, and medication. In this study, we investigate the nonlinear thermophoretic wrinkle motion equation describing wave propagation and thermal-driven deformation in graphene sheets. Governing model is -dimensional graphene sheets (GS) equation, focusing on the component heat transfer during thermodynamic motion. The study employs modified generalized exponential differential function method and the improved Cham method. These techniques are employed to analyze the nonlinear behavior of wave propagation in GS, leading to exact wave solutions such as bright, bell, periodic, and twofold waves. The creative application of these analytical techniques provides efficient structures for tackling complex nonlinear theories in mathematical physics, thereby enhancing solution strategies for these equations. This study makes a notable contribution to computational mathematics, material research, and nanotechnology by providing exact solutions and deepening our comprehension of graphene non linear properties. The findings present significant implications, suggesting potential applications in the design of novel materials with customized properties to facilitate technological progress, thereby expanding the frontiers of nanotechnology and materials research.

In this study, a high sensitive and selective hydrogen peroxide (H2O2) sensor was successfully constructed with Pt-Au bimetallic nanoparticles (Pt-Au NPs)/reduced graphene sheets (rGSs) hybrid films. Various molar ratios of Au to Pt and different electrodeposition conditions were evaluated to control the morphology and electrocatalytic activity of the Pt-Au bimetallic nanoparticles. Upon optimal conditions, wide linear ranges from 1 µM to 1.78 mM and 1.78 mM to 16.8 mM were obtained, with a detection limit as low as 0.31 µM. Besides, due to the synergetic effects of the bimetallic NPs and rGSs, the amperometric H2O2 sensor could operate at a low potential of 0 V. Under this potential, not only common anodic interferences induced from ascorbic acid, uric acid and dopamine, but also the cathodic interference induced from endogenous O2 could be effectively avoided. Furthermore, with rat pheochromocytoma cells (PC 12) as model, the proposed sensor had been successfully used in the detection of H2O2 released from the cancer cells. This method with wide linear ranges and excellent selectivity can provide a promising alternative for H2O2 monitoring in vivo in the fields of physiology, pathology and diagnosis.

We carried out molecular dynamics simulations at various temperatures to predict the thermal conductivity and the thermal conductance of graphene and hexagonal boron-nitride (h-BN) thin films. Therefore, several models with six different grain boundary configurations ranging from 33–140 nm in length were generated. We compared our predicted thermal conductivity of pristine graphene and h-BN with previously conducted experimental data and obtained good agreement. Finally, we computed the thermal conductance of graphene and h-BN sheets for six different grain boundary configurations, five sheet lengths ranging from 33 to 140 nm and three temperatures (i.e., 300 K, 500 K and 700 K). The results show that the thermal conductance remains nearly constant with varying length and temperature for each grain boundary.

In this article, we present the performance of Copper (Cu)/Graphene Nano Sheets (GNS) and C—π (Graphite, GNS, and Nitrogen-doped Graphene Nano Sheets (N—GNS)) as a new battery electrode prototype. The objectives of this research are to develop a number of prototypes of the battery electrode, namely Cu/GNS//Electrolyte//C—π, and to evaluate their respective performances. The GNS, N—GNS, and primary battery electrode prototypes (Cu/GNS/Electrolyte/C—π) were synthesized by using a modified Hummers method; the N-doped sheet was obtained by doping nitrogen at room temperature and the impregnation or the composite techniques, respectively. Commercial primary battery electrodes were also used as a reference in this research. The Graphite, GNS, N—GNS, commercial primary batteries electrode, and battery electrode prototypes were analyzed using an XRD, SEM-EDX, and electrical multimeter, respectively. The research data show that the Cu particles are well deposited on the GNS and N—GNS (XRD and SEM—EDX data). The presence of the Cu metal and electrolytes (NH4Cl and MnO2) materials can increase the electrical conductivities (335.6 S cm−1) and power density versus the energy density (4640.47 W kg−1 and 2557.55 Wh kg−1) of the Cu/GNS//Electrolyte//N—GNS compared to the commercial battery (electrical conductivity (902.2 S cm−1) and power density versus the energy density (76 W kg−1 and 43.95 W kg−1). Based on all of the research data, it may be concluded that Cu/GNS//Electrolyte//N—GNS can be used as a new battery electrode prototype with better performances and electrical activities.

This letter studies the surface heat convection of thin graphene sheets and the application of graphene wires as nanoscale flow and temperature sensors. Graphene wires with relatively large length-to-width ratios were designed and fabricated using bi- and few-layer graphene sheets. Prior to testing, the devices were packaged in a microfluidic chamber with capillary tubes as upstream and downstream connections to minimise environmental interference. The thermal inertia of the graphene wire was studied at 70°C and the flow sensing behaviour of the device was characterised by monitoring normalised resistance changes at different flow rates. The authors experimental results demonstrated the negative temperature coefficients of the bi- and few-layer graphene films. Moreover, the flow sensing resolutions of ∼ 0.07 l/min and 0.1 l/min were achieved from the bi- and few-layer graphene hot wires, respectively. The temperature sensing behaviour of the graphene thermistor was studied in a small temperature range from room temperature to 80°C. The larger negative temperature coefficient of the bi-layer graphene resulted in a higher sensing response than the few-layer one.

Over the last decade, the superior properties of graphene have contributed to intensive studies on the fabrication and applications of graphene nanocomposites. Ex-situ homologous recombination and recombination techniques were listed. Because of their remarkable features, including thermal conductivity and high-specific area, graphene and its derivatives have a significant prospective for medical and biological applications, including drug delivery and bio-imaging. The usage of graphene-based nanomaterials is a hot topic in medicinal research. Many research studies have been performed on graphene-based composites, but only a few reviews have been published regarding their applications in the biomedical field and potential risk factors associated with human well-being and the environment. Hence, this review paper aims to provide in-depth information on ongoing knowledge and results about the properties of graphene-based composites. The discovery, developmental methods, structural properties, and synthesis of graphene nanomaterials have been discussed. After a brief description of the most common methods used for fabricating or extracting graphene derivatives, the main steps of graphene-based composite preparation are introduced. Applications of graphene-based composites in drug delivery, medical, and biomedical fields have been addressed. Finally, the future perspectives and challenges associated with the applications of graphene-based composites have been summarized. Highlights Compositions and characteristics of nanocomposite materials reinforced with graphene, graphene oxide, reduced graphene oxide, and modified graphene. The synthesis method of graphene and the manufacturing of graphene-based composites. Latest developments in graphene-based composites for biomedical applications. Consequences of the large-scale production of graphene-based composites.

Twisted double bilayer graphene (tDBG) comprises two Bernal-stacked bilayer graphene sheets with a twist between them. Gate voltages applied to top and back gates of a tDBG device tune both the flatness and topology of the electronic bands, enabling an unusual level of experimental control. Metallic states with broken spin and valley symmetries have been observed in tDBG devices with twist angles in the range 1.2–1.3°, but the topologies and order parameters of these states have remained unclear. We report the observation of an anomalous Hall effect in the correlated metal state of tDBG, with hysteresis loops spanning hundreds of mT in out-of-plane magnetic field ( B ⊥ ) that demonstrate spontaneously broken time-reversal symmetry. The B ⊥ hysteresis persists for in-plane fields up to several Tesla, suggesting valley (orbital) ferromagnetism. At the same time, the resistivity is strongly affected by even mT-scale values of in-plane magnetic field, pointing to spin-valley coupling or to a direct orbital coupling between in-plane field and the valley degree of freedom. Twisted double bilayer graphene (tDBG) comprises two Bernal-stacked bilayer graphene sheets with a twist between them. Here, the authors report a strong anomalous Hall effect in the correlated-metal regime of tDBG, indicating time reversal symmetry breaking from orbital ferromagnetism, likely associated with valley polarization.

Aqueous Zinc-ion batteries (ZIBs), using zinc negative electrode and aqueous electrolyte, have attracted great attention in energy storage field due to the reliable safety and low-cost. A composite material comprised of VO 2 ·0.2H 2 O nanocuboids anchored on graphene sheets (VOG) is synthesized through a facile and efficient microwave-assisted solvothermal strategy and is used as aqueous ZIBs cathode material. Owing to the synergistic effects between the high conductivity of graphene sheets and the desirable structural features of VO 2 ·0.2H 2 O nanocuboids, the VOG electrode has excellent electronic and ionic transport ability, resulting in superior Zn ions storage performance. The Zn/VOG system delivers ultrahigh specific capacity of 423 mAh·g −1 at 0.25 A·g −1 and exhibits good cycling stability of up to 1,000 cycles at 8 A·g −1 with 87% capacity retention. Systematical structural and elemental characterizations confirm that the interlayer space of VO 2 ·0.2H 2 O nanocuboids can adapt to the reversible Zn ions insertion/extraction. The as-prepared VOG composite is a promising cathode material with remarkable electrochemical performance for low-cost and safe aqueous rechargeable ZIBs.

Catalytic graphitization of kraft lignin to nano-materials was investigated over four transitional metal catalysts (Ni, Cu, Fe, and Mo) through a thermal treatment process under an argon flow at 1000 °C. The catalytic thermal process was examined using thermal gravimetric analysis (TGA) and temperature-programmed decomposition (TPD) experiments. The crystal structure and morphology of the thermal-treated metal-lignin samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. Catalytic graphitization of kraft lignin to nano-materials was investigated over four transitional metal catalysts (Ni, Cu, Fe, and Mo) through a catalytic thermal treatment process. It was observed that multi-layer graphene-encapsulated metal nanoparticles were the main products, beside along with some graphene sheets/flakes. The particle sizes and graphene shell layers were significantly affected by the promoted metals. BET surface areas of samples obtained from different metal precursors were in the range of 88–115 m2/g within the order of Ni- > Fe- > Mo- > Cu-. Thermal gravimetric analysis (TGA) and temperature-programmed decomposition (TPD) experimental results showed that adding transitional metals could promote the decomposition and carbonization of kraft lignin. The catalytic activity increased with an order of Mo≅Cu < Ni≅Fe. XRD results show that face-centered cubic (fcc) Cu crystals is formed in the thermal-treated Cu-lignin sample, fcc nickel phase for the Ni-lignin sample, β-Mo2C hexagonal phase for the Mo-lignin sample and α-Fe, γ-iron, and cementite(Fe3C) for the Fe-lignin sample. Average particle sizes of these crystal phases calculated using the Scherrer formula are 52.4 nm, 56.2 nm, 21.0 nm, 23.3 nm, 11.3 nm, and 32.8 nm for Ni, Cu, β-Mo2C, α-Fe, γ-iron, and Fe3C, respectively. Raman results prove that the graphitization activity of these four metals is in the order of Cu < Mo < Ni < Fe. Metal properties such as catalytic activity, carbon solubility, and tendency of metal carbide formation were related to the graphene-based structure formation during catalytic graphitization of kraft lignin process.

Laser-induced graphene (LIG) uses a CO 2 infrared laser scriber for transforming specific polymer substrates into porous graphene. This technique is simple, scalable, low-cost, free of chemicals, and produces a 3D graphene for applications across many fields. However, the resulting 3D graphene is highly sensitive to the lasing parameters used in their production. Here, we report the effects of power, raster speed, number of lasing passes (with and without spot overlapping) on the resulting LIG structure, morphology, and sheet resistance, using a polyimide (PI) substrate. We find that the number of lasing passes, laser spot overlapping and brand of PI used had a strong influence on the quality of the LIG, measured in terms of the I G /I D and I 2D Raman bands and sheet resistance. Increasing number of passes and overlapping of laser spots led to increased LIG pore sizes, larger graphene scales, and reduced sheet resistance. Furthermore, the over-the-counter desktop CO 2 laser engraving unit used introduced additional restrictions that limited the quality of the LIG produced, particularly due to inconsistent control of the laser scribing speed and a poor thermal management of the laser unit.